BE-75 Duchess
Ground School Text
Table of Contents
(* - Highly Recommended Reading)
*BE-76 Checklists ................................................................................................................................................ 2
*Abbreviated Checklist ....................................................................................................................................... 18
Articles Pertaining to Multi-engine Flight ............................................................................................................ 1
* Always Leave Yourself An Out ..................................................................................................................... 2
* Flying Light Twins Safely ............................................................................................................................ 12
* Transitioning to Twins ................................................................................................................................. 16
* Flight At Minimum Controllable Airspeed .................................................................................................. 23
* Engine-Out Booby Traps for Light Twin Pilots ........................................................................................... 26
* Checkout in a Multiengine Airplane ............................................................................................................ 31
Flying A Multi-Engine Airplane ..................................................................................................................... 51
Twins vs. Singles: The Great Debate .............................................................................................................. 55
Challenges: Multimanager .............................................................................................................................. 59
Are 'Singles' Safer Than 'Twins'? .................................................................................................................... 62
Multi-Engine Airplane Survival ...................................................................................................................... 66
Single vs Twin—Which is Safer? ................................................................................................................... 71
Commentary - Insights .................................................................................................................................... 76
Recurrent Review - Give Me A Brake? .......................................................................................................... 79
Financial Flight Plan - Tax-Deductible Flying................................................................................................ 82
Learning Experiences - Engine Failures.......................................................................................................... 86
Form and Function - Adjustable Screws ......................................................................................................... 89
Recurrent Training - Cockpit Organization ..................................................................................................... 92
Trial By Fire - Some lessons are better learned on the ground ....................................................................... 94
Flying Smart - Letdown Chart......................................................................................................................... 97
Recurrent Training - Ice, Snow and Frost ....................................................................................................... 98
Form And Function - Hidden Wheels ........................................................................................................... 102
Instrument Training - Checklists ................................................................................................................... 105
Ounce of Prevention Suddenly Single - Beyond "dead foot, dead engine".................................................. 108
The Price of Two ........................................................................................................................................... 112
Multi-Engine Pilot Flight Training ................................................................................................................... 115
Lesson Plans for Multi-Engine Course ......................................................................................................... 116
Transition Courses For Complex Single-Engine And Light Twin-Engine Airplanes ................................... 130
Transition Courses For Complex Single-Engine And Light Twin-Engine Airplanes ................................... 130
* Multi-Engine Flying....................................................................................................................................... 138
1.1 Normal Operations .................................................................................................................................. 138
1.2 Engine Out Scenarios .............................................................................................................................. 138
1.3 Engine Out Procedures ............................................................................................................................ 153
1
*BE-76 Checklists
2
SPEEDS FOR SAFE OPERATION (3900 LBS)
Maximum Demonstrated Crosswind Component.
Takeoff
50-ft Speed
Two-Engine Best Angle-of-Climb (VX)
Two-Engine Best Rate-of-Climb (Vy)
Cruise Climb
Turbulent Air Penetration
Landing Approach:
Flaps UP
Flaps DOWN (ON)
Balked Landing Climb
Intentional One-Engine-Inoperative
Speed (V SSE)
Air Minimum Control Speed (VMCA)
25 kts
71 kts
80 kts
71 kts
85 kts
100 kts
132 kts
87 kts
76 kts
71 kts
71 kts
65 kts
PREFLIGHT INSPECTION
1. COCKPIT
Control Lock - REMOVE AND STOW
Parking Brake - SET
All Switches - OFF
Trim Tabs.;. SET TO ZERO
Flush-type Fuel Drain/Emergency Gear Extension Tool - OBTAIN (refer to SYSTEMS section for in~
formation pertaining to flush-type fuel drains). This tool can also be used for opening the oil "and fuel
filler caps.
2. LEFT WING TRAILING EDGE
Flap - CHECK GENERAL CONDITION
Fuel Vent - CHECK, UNOBSTRUCTED
Aileron - CHECK GENERAL CONDITION AND FREEDOM OF MOVEMENT
Wing Tip - CHECK
Position and Strobe Light - CHECK
3. LEFT WING LEADING EDGE
Pitot - REMOVE COVER, EXAMINE FOR OBSTRUCTIONS
Landing and Taxi light - CHECK
Stall Warning Vane - CHECK FREEDOM OF
MOVEMENT
Fuel Tank - CHECK QUANTITY; Cap - SECURE e. Tie down and Chocks - REMOVE
Flush-type Fuel Sump - DRAIN (use fuel--drain tool)
Fuel Selector - DRAIN
Engine Cowling - CHECK CONDITION AND SECURITY
Air Intakes - CLEAR
Propeller -EXAMINE FOR NICKS, SECURITY, AND OIL LEAKS
Engine Oil or CHECK QUANTITY; Cap and Door SECURE
Cowl Flap - CHECK
Wheel Well, Door, Tire, Brake line, and Strut CHECK flush-type
Crossfeed Fuel Drains (2)- DRAIN (use fuel-drain tool)
4. NOSE SECTION
3
Nose Cowling and Nose Cone - CHECK CONDITION AND SECURITY ..
Heater Air Intake - CLEAR
Heater Exhaust and Vents - CLEAR
Wheel Well, Doors, Tire, and Strut - CHECK
5. RIGHT WING LEADING EDGE
Flush-type Crossfeed Fuel Drains (2) - DRAIN (use fuel-drain tool)
Wheel Well, Door, Tire, Brake Line, and Strut CHECK
Engine Cowling - CHECK CONDITION AND SECURITY
Air Intakes - CLEAR
Propeller - EXAMINE FOR NICKS,SECURITY, AND Oil LEAKS
Engine Oil - CHECK QUANTITY; Cap and Door SECURE
Cowl Flap - CHECK h. Fuel Selector s DRAIN
Flush-type Fuel Sump - DRAIN
Tie down and Chocks - RI;MOVE
Fuel Tank – CHECK QUANTITY; Cap - SECURE
Stall Warning Vane - CHECK FREEDOM OF MOVEMENT
Taxi light ... CHECK
Wing Tip - CHECK
Position and Strobe light - CHECK
6. RIGHT WING TRAILING EDGE
Aileron - CHECK CONDITION AND FREEDOM OF MOVEMENT
Fuel Vent - CHECK, UNOBSTRUCTED
Flap - CHECK GENERAL CONDITION
7. FUSELAGE RIGHT SIDE
Battery Vents- CHECK, UNOBSTRUCTED
Static Port - CLEAR OF OBSTRUCTIONS
Emergency Locator Transmitter. - ARMED
8. EMPENNAGE
Control Surfaces and Trim Tabs - CHECK
Tail Cone and Position light - CHECK
Tie down -REMOVE
Cabin Air Inlet - CHECK
9. FUSELAGE LEFT SIDE
Static Port - CLEAR OF OBSTRUCTIONS
Cabin Air Outlet m CHECK
All Antennas - CHECK
Load Distribution - CHECK AND SECURE
Aft Utility Door - CHECK SECURE
NOTE Check operation of lights if .night flight is anticipated.
BEFORE STARTING
1. Fuel Drain/Emergency Extension Tool - STOW
2. Seats - POSITION AND LOCK; Seat Backs -UPRIGHT
3. Seat Belts and Shoulder Harnesses- FASTEN
4. Parking Brake - SET
5. All Avionics - OFF
6. Circuit Breakers - IN
4
7. Landing Gear Handle - DOWN
8. Carburetor Heat - OFF (up position)
9. Cowl Flap Controls ... OPEN (down position)
10. Fuel Selectors - CHECK OPERATION, THEN ON
11. Light Switches - OFF
12 Battery and Alternator Switches - ON
13. Fuel Quantity Indicators - CHECK QUANTITY (See LIMITATIONS for take-off fuel)
14. Landing Gear Position Lights - CHECK
EXTERNAL POWER
The following precautions shall be observed while using external power Exercise caution when connecting
the external power cable to prevent shorting the battery to the airframe or arcing the clamps of the cable
together.
1. Make certain the battery switch is ON and ail avionics, and electrical switches are OFF, and a battery is
in the system before connecting an external power unit This protects the voltage regulators and associated
electrical equipment from voltage transients (power fluctuations).
2. The airplane has a negative ground system. Be sure to connect the positive lead of the auxiliary power
unit to the positive terminal of the airplane's external power receptacle and the negative lead of the
auxiliary power unit to the negative terminal in the external power receptacle.
3. To prevent arcing, make certain no power is being supplied when the connection is made.
STARTING ENGINES USING AUXILIARY POWER UNIT
1. Battery Switch - ON
2. Alternators, Electrical and Avionics Equipment - OFF
3. Auxiliary Power Unit - CONNECT
4. Auxiliary Power Unit • Set OUTPUT 13.5 to 14.25 volts (If 28-volt system - SET OUTPUT 27.0 to
28.5 volts)
5. Auxiliary Power Unit - ON
6. Left Engine - .START (use normal start procedures)
7. Auxiliary Power Unit - OFF (after engine has been started)
8. Auxiliary Power Unit - DISCONNECT (before starting right engine)
9. Alternator Switches - ON
STARTING
1. Battery Switch - ON; Both ALTERNATOR-OUT
2. Under Voltage lights - Illuminated
3. Mixture - Full RICH
4. Propeller - HIGH RPM (low Pitch)
5. Throttle - FAST IDLE (1/4· Travel)
6. Aux Fuel Pump - ON
7. Magneto/Start Switch - Engage starter - PUSH TO PRIME as engine is cranking –Release to 8. BOTH
position when engine starts ..
9. WARNING Do not pump throttles during starting procedures.
Hot Start (Engine· Hot)
a. Mixture .. Full RICH
b. Throttle -FAST IDLE (1/4 Travel)
c. Fuel Boost Pump - OFF
d. Starter -ENGAGE (Do Not Prime)
Flooded /Engine:
a. Mixture - IDLE CUT-OFF
5
b. Throttle - FAST IDLE (114 Travel)
c. Starter - ENGAGE (After 2 to 3 seconds prime briefly, intermittently)
d. Mixture - ADVANCE TO Full RJCH when engine starts.
CAUTION
Maximum starter engage duty cycle is 30 seconds ON, followed by a minimum of two minutes OFF.
7. Engine Warm-up - 1000 to 1200 RPM
2. Oil Pressure - ABOVE RED RADIAL WITHJN 30 SECONDS
3. External Power (if . used) >- DISCONNECT
4. Alternator Switch - ON; CHECK FORCHARGING
5. Starter Engaged Warning Light (if installed) - CHECK; should be illuminated during start and
extinguished after start.
6. Using same procedure. start other engine.
7. left Alternator Switch and Battery Switch - OFF.
8. Check for Left ALTERNATOR-OUT UNDER Voltage Light illuminated, and an indication of less
than 75(%~ (14-volt system) or 40% (28-volt system) on the right load meter.
9. Left Alternator Switch and Battery Switch - ON.
10. Right Alternator Switch and Battery Switch - OFF.
11. Check for Right ALTERNATOR-OUT UNDERVOLTAGE Light illuminated, arid an indication of
less than 75% (14-volt system) or 40% (28-volt system) on the left load meter.
12. Right Alternator Switch and Battery Switch - ON.
CAUTION
If the starter engaged. warning light remains illuminated after starting, or the. load meters and/or
ALTERNATOR-OUT UNDERVOLTAGE lights do not indicate/illuminate properly, an electrical
malfunction is indicated .. The battery switch and both alternator switches should be placed in the OFF
position. Do not take off. If the starter engaged warning light is not installed or is inoperative, and the load
meters and/or ALTERNATOR-OUT UNDERVOLTAGE lights do not indicate/illuminate properly, an
electrical . malfunction is indicated. The battery switch and both alternator switches should be placed in the
OFF position. Do not take off.
AFTER STARTING, AND TAXI
CAUTION
Never taxi with a flat tire or flat shock strut. During taxi operations. particular attention should be given to
propeller tip clearance. Extreme caution is required when. operating on unimproved or irregular. surfaces or
when high winds exist.
1. Avionics - ON, AS REQUIRED
2. lights - AS REQUIRED
NOTE
Turn strobe lights off when taxiing in the vicinity of other aircraft or when flying in fog or. clouds. Standard
position lights are to be used for all night operations.
3. Annunciator Warning lights - PRESS- TO-TEST
4. Aux Fuel Pumps - OFF, THEN ON (check fuel pressure indicators to verify operation of engine-driven pumps)
5. All Engine Instruments - CHECK 6. Brakes m RELEASE AND CHECK
CAUTION
6
Detuning the counterweight system of the engine can occur by rapid throttle operation, high rpm (low pitch)
and low manifold pressure, or propeller feathering. (See latest revision of Lycoming Service Bulletin No. 245.)
BEFORE TAKEOFF
1. Seat Belts and Shoulder Harnesses - CHECK
2. Parking Brake - SET
3. Radios - CHECK
4. Flight Instruments - CHECK AND SET
5. Engine Instruments - CHECK
6. Starter Engaged Warning light (if installed) - CHECK (should not be lit). If light is not installed or is
inoperative, monitor load meters for proper indications.
7. Fuel Selectors - ON
8. Flight Controls - CHECK PROPER DIRECTION AND FREEDOM OF MOVEMENT
9. Wing Flaps - CHECK OPERATION
10. Electric Trim - CHECK OPERATION
11. Trim - SET TO TAKE-OFF RANGE
12. Throttles - 2200 RPM
13. Propellers - EXERCISE (100-200 rpm drop)
14. Magnetos - CHECK (175 rpm maximum· drop, within 50 rpm of each other)
NOTE
Avoid operation on one magneto for more than 5 to 10 seconds. If rpm drop is excessive, lean to smooth
operation and recheck.
15. Carburetor Heat- CHECK and set OFF (cold) for takeoff
16. Throttles - 1500 RPM
17. Propellers - FEATHER CHECK (Do not exceed 500 rpm "drop.) Repeat 3 or 4 times
weather.
18. Gyro Pressure and Load meters -CHECK
19. Throttles - IDLE
20. Aux Fuel Pumps - CHECK ON
21. Doors and Window • SECURE
22. Parking Brake - RELEASE 23. Engine Instruments - CHECK
cold
TAKEOFF
Takeoff Power Full Throttle, 2700 rpm
1. Power - SET TAKE-OFF POWER (before brake release)
2. Mixtures - FULL RICH or lean to smooth operation as required by field elevation
3. Airspeed - ACCELERATE TO AND MAINTAIN TAKE-OFF SPEED
4. Landing Gear - RETRACT when airplane is positively airborne
5. Airspeed - ESTABLISH DESIRED CUMB SPEED when clear of obstacles
NOTE
If red in-transit light remains illuminated after 30 seconds, place landing gear switch handle in the down
position, make a normal landing and have the landing gear system checked.
CLIMB
Maximum Climb Full Throttle, 2700 RPM
Cruise Climb Full Throttle, 2600 RPM
1. Engine Temperatures - MONITOR
2. Power - SET
3. Mixtures -LEAN AS REQUIRED
4. Cowl Flaps - AS REQUIRED 5. Aux Fuel Pumps - OFF
7
CRUISE
Maximum Cruise Power .......
Recommended Cruise Power
Recommended Cruise Power
Economy Cruise Power
24.0 in. Hg or full throttle, at 2700 wpm
4.0 in. Hg or full throttle, at 2500 rpm
24.0 in. Hg or full throttle, at 2300 wpm
20.0 in. Hg or full throttle. at 2300 rpm
1. Power - SET AS DESIRED (Use Tables in PERFORMANCE section)
2. Mixtures - LEAN AS REQUIRED
3. Cowl Flaps - AS REQUIRED
LEANING MIXTURE USING THE EXHAUST GAS TEMPERATURE INDICATOR (EGT)
For level flight at 15% power or less, the EGT unit should be used In the following manner:
Lean the mixture and note the point on the indicator at which the temperature peaks and starts to fall.
a. CRUISE (LEAN) MIXTURE· Enrich mixture (push mixture control forward) until EGT indicator shows a
drop of 25°F to SO°F on rich side of peak.
b. BEST POWER MIXTURE - Enrich mixture (push mixture control forward) until EGT indicator shows a
drop of 1SoF to 100°F on rich side of peak.
CAUTION
Do not continue to lean mixture beyond the point necessary to establish peak temperature. Continuous
operation is recommended at 2SoF or below peak EGT only on rich side of peak.
Changes in altitude and power setting require EGT to be rechecked and mixture reset.
A mixture resulting in an EGT 2SoF on the rich side of peak should also result· in fuel flow and T AS values
approximately equal to those presented in the Cruise Power Settings tables in the PERFORMANCE Section. If
not the values derived from the Range, Endurance, and Cruise Speeds charts must be revised accordingly. In
very cold weather, EGT's 2SoF rich of peak may not be obtainable.
DESCENT
1. Altimeter ~ SET
2. Cowl Flaps - CLOSE
3. Windshield Defroster - AS REQUIRED
4. Carburetor Heat • FULL ON or FULL OFF, AS REQUIRED
5. Power - AS REQUIRED (avoid prolonged idle settings and low cylinder head temperatures)
6. Mixtures - ENRICH AS REQUIRED
BEFORE LANDING
1. Seat Belts and Shoulder Harnesses - FASTENED, SEAT BACKS UPRIGHT
2. Fuel Selectors - CHECK ON
3. Aux Fuel Pumps - 0(\,1
4. Mixture Controls - FULL RICH (or as required by field elevation)
5. Carburetor Heat - FULL ON or FULL OFF AS Required
NOTE In the event of a go-around, Carburetor Heat shall !be in the full OFF (cold) position after full throttle
application.
6. Cowl Flaps - AS REQUIRED
7. Landing Gear - DOWN (140 KTS Maximum)
8. Landing and Taxi lights - AS REQUIRED
9. Wing Flaps - FULL DOWN (DN) (110 KTS Maximum)
10. Airspeed - ESTABLISH LAN[)ING APPROACH SPEED
11 . Propellers - HIGH RPM
8
BALKED LANDING
1. Propellers - HIGH RPM
2. Throttles - FULL FORWARD
3. Airspeed - 71 KTS
4. Wing Flaps - UP
5. Landing Gear - UP
6. Cowl Flaps - AS REQUIRED
AFTER LANDING
1. Landing and Taxi Lights - AS REQUIRED
2. Wing Flaps - UP
3. Trim Tabs - SET TO TAKE-OFF RANGE
4. Cowl Flaps - OPEN
SHUTDOWN
1. Parking Brake - SET
2. Fuel Pumps - OFF
3. Electrical and Avionics Equipment - OFF
4. Propellers - HIGH RPM
5. Throttles - 1000 RPM
6. Mixtures - IDLE CUT-OFF
7. Magneto/Start Switches - OFF, after engines stop
8. Battery and Alternator Switches - OFF
9. Controls - LOCKED
10. Install wheel chocks and release brakes if the airplane is to be left unattended.
ENVIRONMENTAL SYSTEMS HEATING AND VENTILATION
Refer to the SYSTEMS DESCRIPTION section fm operation of heating and ventilation controls.
ELECTRIC ELEVATOR TRIM
1. On/Off Switch - ON
2. Control Wheel Trim Switch ~ Depress and move forward from nose down, aft fm nose up, and when
released, the switch returns to the center (OFF) position.
Procedure for UNSCHEDULED ELECTRIC ELEVATOR TRIM is given in EMERGENCY PROCEDURES
Section.
PRACTICE DEMONSTRATION OF YMCA
YMCA demonstration. may be required for multi-engine pilot certification. The. following procedure shall be
used at a safe altitude of at least 5000 feet ab9ve the ground in clear air only.
WARNING
INFUGHT ENGINE CUTS BELOW VSSE SPEED OF 71 KTS ARE PROHIBITED.
1. Landing Gear - UP
2. Wing Flaps - UP
3. Airspeed - ABOVE 71 KTS (VSSE)
4. Propeller Levers - HIGH RPM
5. Throttle (simulated inoperative. engine) -IDLE
6. Throttle (other engine) - FULL FORWARD
7. Airspeed - REDUCE approximately 1 .knot per second until either VMCA or stall warning is obtained.
9
CAUTION
Use rudder to maintain directional control (heading) and ··ailerons to maintain 5° bank towards the operative
engine (lateral attitude). At the first sign of either YMCA or stall warning (which may be evidenced by:
inability to maintain heading or lateral attitude, aerodynamic stall buffet, or stall warning horn sound)
immediately inmate recovery: reduce power to idle on the operative engine and immediately lower the nose to
regain VSSE.
10
EMERGENCY PROCEDURES
EMERGENCY AIRSPEEDS (3900 LBS)
One-Engine-Inoperative Best Angle-of-Climb (Vx)
One-Engine-Inoper!itive Best Rate-of-Climb Vy)
Air Minimum Control Speed (VMCA)
One-Engine-Inoperative Enroute Climb
Emergency Descent
One-Engine-Inoperative landing:
Maneuvering to Final Approach
Final Approach (FIaps Down)
Intentional One-Engine-Inoperative Speed (VSSE)
Maximum Glide Range
85 kts
85 kts
· 65 kts
85 kts
140 kts
90 kts
85 kts
11 kts
95 kts
Stall warning horn is inoperative when the Battery and Alternator Switches are turned off.
The following information is presented to enable the pilot to form, in advance, a definite plan of action for
coping with the most probable emergency situations which could occur in the operation of the airplane. Where
practicable, the emergencies requiring immediate corrective action are treated in check list form for easy
reference and familiarization. Other situations, in which more time is usually permitted to decide on and
execute a plan of action, are discussed at some length.
ONE-ENGINE OPERATION
Two major factors govern one· engine operations; airspeed and directional control. The airplane can be safely
maneuvered or trimmed for normal hands-off operation and sustained in this configuration by the operative
engine AS LONG AS SUFFICIENT AIRSPEED IS MAINTAINED.
The following checks will help determine which engine has failed:
DEAD FOOT - DEAD ENGINE. The rudder pressure required to maintain directional control will 00 on the
side of the operative engine.
THROTTLE. Partially retard the throttle for the engine that is believed to be inoperative; there· should be no
change in control pressures or in the sound. of the engine if the correct throttle has. been. selected. AT LOW
ALTITUDE AND AIRSPEED THIS CHECK MUST BE ACCOMPLISHED WITH EXTREME CAUTION.
Do not attempt to determine the inoperative engine by means of the tachometers or the manifold pressure
gages. These instruments often indicate near normal readings.
ONE-ENGENE~INOPERATSVE PROCEDURES
ENGINE FAILURE DURING GROUND ROLL
1. Throttles - IDLE
2. Braking - MAXIMUM
3. Fuel Selectors - OFF
4. Battery, Alternator, and Magneto/Start Switches - OFF
NOTE Braking effectiveness is improved if the brakes are not locked.
ENGINE FAILURE AFTER LIFTOFF AND IN FLIGHT
An immediate landing is advisable regardless of take-off weight. Continued flight can not be assured if takeoff weight exceeds the weight determined from the TAKE~OFF WEIGHT graph. Higher takeoff weights will
result in a loss of altitude while retracting the landing gear and feathering the propeller. Continued flight
requires immediate pilot response to the following procedures:
1. Landing Gear and Flaps ~ UP
2. Throttle (inoperative engine) - IDLE
11
3. Propeller (inoperative engine) - FEATHER
4. Power (operative engine) - AS REQUIRED
5. Airspeed -AT OR ABOVE THE 50-FT TAKE-OFF SPEED (80 KNOTS)
6. After positive control of the airplane is established:
7. Secure inoperative engine:
a.. Mixture Control - IDLE CUT-OFF
b. Fuel Selector - OFF
c. Aux Fuel Pump - OFF
d. Magneto/Start Switch - OFF
e. Alternator Switch - OFF
f. Cowl Flap - CLOSE
8. Airspeed - ESTABLISH 85 KTS
9. Electrical load - MONITOR (Maximum load of 100% on remaining engine)
NOTE
The most important aspect of engine failure is the necessity to maintain lateral and directional control. If
airspeed is below 65 knots, reduce power on operative engine as required to maintain control. Refer to the
SAFETY INFORMATION section for additional information regarding pilot technique.
AIR START
CAUTION The pilot should determine the reason for engine failure before attempting an air start.
NOTE Airspeed should be maintained. at or above 100 KIAS to ensure the engine will windmill.
WITH UNFEATHERING ACCUMULA TORS:
1 . Fuel Selector - ON
2. Throttle - SET approximately ¼ in travel
3. Aux Fuel Pump - ON
4. Magneto/Start Switch - BOTH
5. Propeller Control - MOVE FULL FORWARD UNTIL ENGINE WINDMILLS, THEN BACK TO
MIDRANGE. USE STARTER MOMENTARILY IF AIRSPIEED IS BELOW 100 KTS.
If propeller does not unfeather or engine does not turn, proceed to WITHOUT UNFEATHERING
ACCUMULATORS procedure.
6. Mixture - FULL RICH
7. If engine fails to run, clear engine by allowing it to windmill with mixture in the FULL LEAN position.
8. When engine fires, advance mixture to FULL RICH.
9. When Engine Starts m ADJUST THROTTLE , PROPELLER, AND MIXTURE CONTROLS
10. Aux Fuel Pump - OFF (when reliable power has been regained)
11. Alternator Switch ON
12. Oil Pressure and Oil Temperature .. CHECK
13. Warm Up Engine (approximately 2000 rpm and 15 in. HG)
14. Set power as required and trim.
WITHOUT UNFEA THERING ACCUMULATORS:
CAUTION Numerous air starts without unfeathering accumulators can shorten engine-mount life.
1. Fuel Selector - ON
2. Throttle: SET approximately V4 travel
3. Aux Fuel Pump - ON
4. Magneto/Start Switch - BOTH
5. Mixture - FULL RICH
6. Propeller Control & MOVE FORWARD OF FEATHERING DETENT TO MIDRANGE
7. Magneto/Start Switch - START and PUSH TO PRIME (hold on START until windmilling begins and
continue to prime as required)
12
NOTE If air start is unsuccessful, return propeller control to the FEATHER position and secure engine.
8. When Engine Starts - ADJUST THROTTLE, PROPELLER, AND MIXTURE CONTROLS
9. Aux Fuel Pump - OFF (when reliable power has been regained)
10. Alternator Switch - ON
11. Oil Pressure and Oil Temperature -CHECK
12. Warm Up Engine (approximately 2000 rpm and 15 in. Hg)
13. Set power as required and trim.
ENGINE FIRE (GROUND)
1. Mixture Controls - IDLE CUT-OFF
2. Continue to crank affected engine
3. Fuel Selectors - OFF
4. Battery and Alternator Switches - OFF
5. Extinguish fire with extinguisher
ENGINE FIRE IN FLIGHT
1. Shut down the affected engine according to the. following procedure and land immediately. Follow the
applicable single-engine procedures in this section.
2. Fuel Selector - OFF
3. Mixture Control - IDLE CUT-OFF
4. Propeller -FEATHER
5. Aux Fuel Pump - OFF
6. Magneto/Start Switch - OFF
7. Alternator Switch - OFF
EMERGENCY DESCENT
1 . Propellers - 2700 RPM
2. Throttles - IDLE
3. Airspeed - 140 KTS
4. Landing Gear - DOWN
MAXIMUM GLIDE CONFIGURATION
1. Propellers - FEATHER
2. Wing Flaps - UP
3. Landing Gear - UP
4. Cowl Flaps - CLOSE
5. Airspeed - 95 KTS
The glide ratio in this configuration is approximately 2 nautical miles of gliding distance for each 1000 feet of
altitude above the terrain.
LANDING EMERGENCIES
GEAR-UP LANDING
If possible, choose firm sod or foamed runway. When assured of reaching the landing site:
1. Cowl Flaps - CLOSE
2. Wing Flaps ~ FULL DOWN (ON)
3. Throttles. - IDLE
4. Mixture Controls - IDLE CUT-OFF
5. Battery, Alternator, and Magneto/Start Switches - OFF
6. Fuel Selectors - OFF
7. Keep wings level during touchdown.
8. Get clear of the airplane as soon as possible after it stops.
13
NOTE The gear-up landing procedures are based on the best available information and no actual tests have
been conducted.
ONE-ENGINE-INOPERATIVE LANDING
On final approach and when it is certain that the field can be reached:
1 . Landing Gear ~ DOWN
2. Airspeed - 85 KTS
3. Power - AS REQUIRED
4. When it is certain there is no possibility of go-around: Wing Flaps - FULL DOWN (DN)
5. Execute normal landing.
ONE-ENGINE-INOPERATIVE GO-AROUND
WARNING Level flight may not be possible for certain combinations of weight, temperature and altitude. In
any event, DO NOT attempt a one-engine inoperative go-around after flaps have been fully extended.
1. Power - MAXIMUM ALLOWABLE
2. Landing Gear - UP
3. Wing Flaps - UP
4. Airspeed - MAINTAIN 85 KTS MINIMUM
SYSTEMS EMERGENCIES
OPERATION ON CROSSFEED
NOTE The fuel crossfeed system is to be used during emergency conditions in level flight only.
Left Engine Inoperative:
1. Right Aux Fuel Pump - ON
2. Left Fuel Selector ~ OFF
3. Right Fuel Selector - CROSS FEED
4. Right Aux Fuel Pump - ON or OFF as required
Right Engine Inoperative:
1. Left Aux Fuel Pump - ON
2. Right Fuel Selector - OFF
3. Left Fuel Selector -CROSS FEED
4. Left Aux Fuel Pump - ON or OFF as required
ELECTRICAL SMOKE OR FIRE
Action to be taken must consider existing conditions and (1quipment installed:
1 . Battery and Alternator Switches - OFF
WARNING Electrically driven instruments and stall warning horn will become inoperative.
2. All Electrical Switches - OFF
3. Battery and Alternator Switches - ON
4. Essential Electrical Equipment· ON (Isolate defective equipment)
NOTE Ensure fire is out and will not be aggravated by draft. Turn off CABIN HEAT switch and push in the
CABIN AIR control. To aid in smoke evacuation, open pilot's storm window if required.
COMPLETE LOSS OF ELECTRICAL POWER INDICATIONS
Dimming of lights. with loadmeters showing 100% or much greater than normal, or load meters showing 0%,
accompanied by no ALTERNATOR-OUT Lights.
ACTION
1. Both Alternator Switches - OFF
2. Battery Switch - OFF
3. Both BUS-ISO Circuit Breakers -PULL
14
4. Remove all electrical loads.
5. Both Alternator Switches - ON.
6. Minimize all electrical loads. Select only that electrical equipment which is essential for safe flight.
7, Extend landing gear with emergency system.
8. LAND AS SOON AS PRACTICAL; HAVE THE COMPLETE ELECTRICAL SYSTEM CHECKED
BEFORE THE NEXT FLIGHT.
CAUTION Since the battery is off line when this procedure is used, large changes in electrical load should be
minimized in order to reduce the· possibility of damage to electrical components.
ILLUMINATION OF ALTERNATOR-OUT LIGHT
In the event of the illumination of a single ALTERNA TOR-OUT UNDERVOLTAGE light or a single
ALTERNATOR-OUT OVERVOL TAGE light:
1. Check the respective loadmeter for load indication:
2. No load - Turn off affected alternator.
3. Reduce load to single alternator capability.
4. Reset the affected alternator with the alternator switch. Monitor over voltage and under voltage lights
and loadmeter for proper operation.
CAUTION If proper operation is not restored, turn alternator switch OFF.
In the event of the illumination of both AL TERNA TOR-OUT UNDERVOLTAGE lights Of both
ALTERNATOR-OUT OVERVOLTAGE lights:
1. Check loadmeters for load indication. If condition indicates malfunction of both alternator circuits:
2. Both ALT Switches - OFF
3. Minimize electrical load since only battery power will be available.
4. Reset the alternators with the alternator switches.
5. Monitor over voltage and under voltage lights and loadmeters for proper operation.
CAUTION If proper operation is not restored, turn alternator switches OFF.
STARTER ENGAGED WARNING LIGHT ILLUMINATED (If installed)
After engine start, should the starter relay remain engaged. the starter will remain energized and the starter
engaged warning light will remain illuminated. Continuing to supply power to the starter will result in eventual
loss of electrical power.
Illuminated On the Ground:
1. Battery and Alternator Switches ~ OFF
2, Do not take off
Illuminated In Flight After Air Start:
1, Perform action for COMPLETE LOSS OF ELECTRICAL POWER (see this section)
2, land as soon as practical
UNSCHEDULED ELECTRIC ELEVATOR TRIM
1. Airplane Attitude - MAINTAIN using elevator control.
2. Elevator Trim Thumb Switch (on/control wheel) DEPRESS .AND MOVE IN DIRECTION
OPPOSITE UNSCHEDULED PITCH TRIM.
3. Elevator Trim ON-OFF Switch (on instrument panel) OFF
4. Manual Elevator Trim Control Wheel - RETRIM AS DESIRED
15
NOTE Do not attempt to operate the electric trim system until the cause of the malfunction has been
determined and corrected.
LANDING GEAR MANUAL EXTENSION
Reduce airspeed before attempting manual extension of the landing gear.
1. Landing GEAR MOTOR Circuit Breaker - OFF (pull out)
2. Landing Gear Switch Handle - DOWN position
3. Airspeed - 100 KTS MAXIMUM
4. Emergency Extension Valve - OPEN (Use Emergency Extension Wrench ~ Turn Counterclockwise)
If electrical system is operative, check landing gear position lights and warning horn. (Check landing GEAR
CONTROL circuit breaker engaged.)
WARNING After emergency landing gear extension, do not move any landing gear controls or reset any
switches or circuit breakers until airplane is on jacks, as failure may have been in the gear-up circuit and gear
might retract with the airplane on the ground.
LANDING GEAR RETRACTION AFTER PRACTICE MANUAL EXTENSION
After practice manual extension of the landing gear, the gear can only be retracted electrically, as follows:
CAUTION Do not operate landing gear electrically, or turn on landing light or taxi light, if battery is off the
line.
1 . Emergency Extension Valve· CLOSE (Use Emergency Extension Wrench - Turn Clockwise)
2. Landing GEAR MOTOR Circuit Breaker - ON (push in)
3. Landing Gear Switch Handle - UP
ALTERNATE STATIC AIR SOURCE
THE ALTERNATE STATIC AIR SOURCE SHOULD BE USED FOR CONDITIONS WHERE THE
NORMAL STATIC SOURCE HAS BEEN OBSTRUCTED. When the airplane has been exposed to moisture
and/or icing conditions (especially on the ground), the possibility of obstructed static ports should be
considered. Partial obstruction will result in the rate-of-climb indication being sluggish during a climb or descent Verification of suspected obstruction is possible by switching to the alternate system and noting a sudden
sustained change in rate of climb. This may be accompanied by abnormal .indicated airspeed and altitude
changes beyond normal calibration differences.
Whenever any obstruction exists in the Normal Static Air System, or the Alternate Static Air System is desired
for use:
1. Pilot's Alternate Static Air Source - Switch to ON ALTERNATE (lower sidewall adjacent to pilot)
2. For Airspeed Calibration and Altimeter Correction, refer to PERFORMANCE section.
NOTE The alternate static air valve should remain in the OFF NORMAL position when system is not needed.
EMERGENCY EXIT
The forward cabin doors and/or the aft utility door may be used for egress if required.
SIMULATED ONE-ENGINE INOPERATIVE ZERO THRUST (Simulated Feather)
Use the following power setting (only on one engine at a time) to establish zero thrust. Use of this power
setting avoids the difficulties of restarting an engine and preserves the availability of power to counter
potential hazards.
1. Throttle Lever - SET 8.0 in. Hg MANIFOLD PRESSURE
16
2. Propeller lever - RETARD TO FEATHER DETENT
NOTE This setting will approximate Zero Thrust using recommended one-engine-inoperative climb speeds.
UNLATCHED DOOR IN FLIGHT
If the cabin door is not secured it may come unlatched in flight This usually occurs during or just after takeoff.
The door will trail in a position approximately 3 inches open. A buffet may be encountered with the door open
in flight Return to the field in a normal manner. If practicable, during the landing flare-out have a passenger
hold the door to prevent it from swinging open.
SPINS
If a Spin is Entered Inadvertently:
Immediately move the control column full forward, apply full rudder opposite to the direction of the spin and
reduce power on both engines to idle. These three actions should be done as nearly simultaneously as possible;
then continue to hold this control position until rotation stops and then neutralize all controls and execute a
smooth pullout Ailerons should be neutral during recovery.
NOTE
Federal Aviation Administration Regulations do not require spin demonstration of airplanes of this class;
therefore, no spin tests have been conducted. The recovery technique is based on the best available
information.
17
*Abbreviated Checklist
18
3. LEFT WING LEADING EDGE
Pitot - REMOVE COVER, OBTRUCTIONS
Landing and Taxi light - CHECK
Stall Warning Vane - CHECK
Fuel Tank - CHECK QUANTITY
Cap - SECURE
Tie down and Chocks - REMOVE
Fuel Selector - DRAIN
Engine Cowling – CONDITION, SECURITY
Air Intakes - CLEAR
Propeller - NICKS, SECURITY, OIL LEAKS
Engine Oil or CHECK QUANTITY
Cap and Door SECURE
Cowl Flap - CHECK
Wheel Well, Door CHECK
Tire, Brake line, and Strut CHECK
Crossfeed Fuel Drains (2)- DRAIN
BE-76 Duchess
SPEEDS FOR SAFE OPERATION (3900 LBS)
Maximum Crosswind Component.
25 kts
Takeoff
71 kts
50-ft Speed
80 kts
Best Angle-Climb (VX)
71 kts
Best Rate-of-Climb (Vy)
85 kts
Cruise Climb
100 kts
Turbulent Air Penetration
132 kts
Landing Approach:
Flaps UP
87 kts
Flaps DOWN (ON)
76 kts
Balked Landing Climb
71 kts
Intentional Engine-Inoperative
V SSE
71 kts
VMCA
65 kts
4. NOSE SECTION
Nose Cowling and Nose Cone - CHECK CONDITION AND
SECURITY ..
Heater Air Intake - CLEAR
Heater Exhaust and Vents - CLEAR
Wheel Well, Doors, Tire, and Strut - CHECK
5. RIGHT WING LEADING EDGE
Crossfeed Fuel Drains (2) - DRAIN
Wheel Well, Door CHECK
Tire, Brake Line, and Strut CHECK
Engine Cowling - CONDITION AND SECURITY
Air Intakes - CLEAR
Propeller - NICKS,SECURITY, Oil LEAKS
Engine Oil - CHECK QUANTITY
Cap and Door SECURE
Cowl Flap - CHECK Fuel Selector s DRAIN
Flush-type Fuel Sump - DRAIN
Tie down and Chocks - REMOVE
Fuel Tank – CHECK QUANTITY
Cap - SECURE
Stall Warning Vane - MOVEMENT
Taxi light ... CHECK
Wing Tip - CHECK
Position and Strobe light - CHECK
Normal Operations
PREFLIGHT INSPECTION
1. COCKPIT
Control Lock - REMOVE AND STOW
Parking Brake - SET
All Switches - OFF
Trim Tabs.;. SET TO ZERO
Flush-type Fuel Drain/Emergency Gear Extension Tool - OBTAIN
2. LEFT WING TRAILING EDGE
Flap - CHECK GENERAL CONDITION
Fuel Vent - CHECK, UNOBSTRUCTED
Aileron - CONDITION AND FREEDOM
Wing Tip - CHECK
Position and Strobe Light - CHECK
1
6. RIGHT WING TRAILING EDGE
Aileron - CONDITION AND MOVEMENT
Fuel Vent - CHECK, UNOBSTRUCTED
Flap - CHECK GENERAL CONDITION
5. APU - ON
6. Left Engine - .START (use normal start)
7. APU - OFF after engine started
8. APU - DISCONNECT before starting right eng
9. Alternator Switches - ON
7. FUSELAGE RIGHT SIDE
Battery Vents- CHECK, UNOBSTRUCTED
Static Port - CLEAR OF OBSTRUCTIONS
Emergency Locator Transmitter. - ARMED
STARTING
1. Battery Switch - ON; Both ALTERNATOR-OUT
2. Under Voltage lights - Illuminated
3. Mixture - Full RICH
4. Propeller - HIGH RPM (low Pitch)
5. Throttle - FAST IDLE (1/4· Travel)
6. Aux Fuel Pump - ON
7. Magneto/Start Switch - Engage starter - PUSH TO PRIME as engine
is cranking
8. EMPENNAGE
Control Surfaces and Trim Tabs - CHECK
Tail Cone and Position light - CHECK
Tie down -REMOVE
Cabin Air Inlet - CHECK
9. FUSELAGE LEFT SIDE
Static Port - CLEAR OF OBSTRUCTIONS
Cabin Air Outlet m CHECK
All Antennas - CHECK
Load Distribution - CHECK AND SECURE
Aft Utility Door - CHECK SECURE
Hot Start (Engine· Hot)
a. Mixture .. Full RICH
b. Throttle -FAST IDLE (1/4 Travel)
c. Fuel Boost Pump - OFF
d. Starter -ENGAGE (Do Not Prime)
Flooded /Engine:
a. Mixture - IDLE CUT-OFF
b. Throttle - FAST IDLE (114 Travel)
c. Starter - ENGAGE
d. Mixture - Full RJCH when engine starts.
BEFORE STARTING
1. Emergency Extension Tool - STOW
2. Seats - POSITION AND LOCK
3. Seat Belts and Shoulder Harnesses- FASTEN
4. Parking Brake - SET
5. All Avionics - OFF
6. Circuit Breakers - IN
7. Landing Gear Handle - DOWN
8. Carburetor Heat - OFF (up position)
9. Cowl Flap Controls ... OPEN (down position)
10. Fuel Selectors - ON
11. Light Switches - OFF
12 Battery and Alternator Switches - ON
13. Fuel Quantity Indicators - QUANTITY
14. Landing Gear Position Lights - CHECK
Maximum starter engage is 30 seconds ON, followed by a
minimum of two minutes OFF.
8. Engine Warm-up - 1000 to 1200 RPM
9. Oil Pressure - ABOVE RED RADIAL WITHJN 30 SECONDS
10. External Power (if . used) >- DISCONNECT
11. Alternator Switch - ON; CHECK CHARGING
12. Starter Engaged Light (if installed) - CHECK
13. Using same procedure. start other engine.
14. left Alternator Switch and Battery Switch - OFF.
15. Check for Left ALTERNATOR16. Left Alternator Switch/Battery Switch - ON.
17. Right Alternator Switch/Battery Switch - OFF.
18. Check for Right ALTERNATOR-OUT
19. Right Alternator Switch/Battery Switch - ON.
STARTING ENGINES USING AUXILIARY POWER UNIT
1. Battery Switch - ON
2. Alternators, Electrical and Avionics Equipment - OFF
3. APU - CONNECT
4. APU • Set OUTPUT
2
AFTER STARTING, AND TAXI
1. Avionics - ON, AS REQUIRED
2. lights - AS REQUIRED
3. Annunciator Warning lights - PRESS- TO-TEST
4. Aux Fuel Pumps - OFF, THEN ON
5. All Engine Instruments - CHECK
6. Brakes m RELEASE AND CHECK
CLIMB
Maximum Climb Full Throttle, 2700 RPM
Cruise Climb Full Throttle, 2600 RPM
1. Engine Temperatures - MONITOR
2. Power - SET
3. Mixtures -LEAN AS REQUIRED
4. Cowl Flaps - AS REQUIRED 5. Aux Fuel Pumps - OFF
BEFORE TAKEOFF
1. Seat Belts and Shoulder Harnesses - CHECK
2. Parking Brake - SET
3. Radios - CHECK
4. Flight Instruments - CHECK AND SET
5. Engine Instruments - CHECK
6. Starter Engaged Warning light (
7. Fuel Selectors - ON
8. Flight Controls – DIRECTION/FREEDOM
9. Wing Flaps - CHECK OPERATION
10. Electric Trim - CHECK OPERATION
11. Trim - SET TO TAKE-OFF RANGE
12. Throttles - 2200 RPM
13. Propellers - EXERCISE (100-200 rpm drop)
14. Magnetos - CHECK
15. Carburetor Heat- CHECK and set OFF
16. Throttles - 1500 RPM
17. Propellers - FEATHER CHECK
18. Gyro Pressure and Load meters -CHECK
19. Throttles - IDLE
20. Aux Fuel Pumps - CHECK ON
21. Doors and Window • SECURE
22. Parking Brake - RELEASE
23. Engine Instruments - CHECK
24 Transponder – ALT
25. Avionics - SET
CRUISE
Maximum Cruise Power -24.0 in. 2700 rpm
Recommended Cruise Power - 24.0 in. 2500 rpm
Recommended Cruise Power - 24.0 in. Hg 2300 wpm
Economy Cruise Power- 20.0 in. Hg 2300 rpm
1. Power - SET AS DESIRED
2. Mixtures - LEAN AS REQUIRED
3. Cowl Flaps - AS REQUIRED
DESCENT
1. Altimeter ~ SET
2. Cowl Flaps - CLOSE
3. Windshield Defroster - AS REQUIRED
4. Carburetor Heat • AS REQUIRED
5. Power - AS REQUIRED
6. Mixtures - ENRICH AS REQUIRED
BEFORE LANDING
1. Seat Belts Harnesses – FASTENED
2. Fuel Selectors - CHECK ON
3. Aux Fuel Pumps - ON
4. Mixture Controls - FULL RICH
5. Carburetor Heat - AS Required
6. Cowl Flaps - AS REQUIRED
7. Landing Gear - DOWN (140 KTS Maximum)
8. Landing and Taxi lights - AS REQUIRED
9. Wing Flaps - FULL DOWN (110 KTS Max)
10. Airspeed - APPROACH SPEED
11 . Propellers - HIGH RPM
TAKEOFF
Takeoff Power Full Throttle, 2700 rpm
1. Power - SET TAKE-OFF POWER
2. Mixtures - SET
3. Airspeed - ACCELERATE TAKE-OFF SPEED
4. Landing Gear - RETRACT when positive ROC
5. Airspeed - ESTABLISH CUMB SPEED
BALKED LANDING
1. Propellers - HIGH RPM
2. Throttles - FULL FORWARD
3. Airspeed - 71 KTS
4. Wing Flaps - UP
3
5. Landing Gear - UP
6. Cowl Flaps - AS REQUIRED
EMERGENCY PROCEDURES
EMERGENCY AIRSPEEDS (3900 LBS)
One-Engine-Inoperative Best Angle-of-Climb (Vxse)
One-Engine- Inoperative Best Rate-of-Climb Vyse)
Air Minimum Control Speed (VMCA)
One-Engine-Inoperative Enroute Climb
Emergency Descent
One-Engine-Inoperative landing:
Maneuvering to Final Approach
Final Approach (FIaps Down)
Intentional One-Engine-Inoperative Speed (VSSE)
Maximum Glide Range
AFTER LANDING
1. Landing and Taxi Lights - AS REQUIRED
2. Wing Flaps - UP
3. Trim Tabs - SET TO TAKE-OFF RANGE
4. Cowl Flaps - OPEN
SHUTDOWN
1. Parking Brake - SET
2. Fuel Pumps - OFF
3. Electrical and Avionics Equipment - OFF
4. Propellers - HIGH RPM
5. Throttles - 1000 RPM
6. Mixtures - IDLE CUT-OFF
7. Magneto/Start Switches - OFF,
8. Battery and Alternator Switches - OFF
9. Controls - LOCKED
10. Install wheel chocks and release brakes if the airplane is to be left
unattended.
85 kts
85 kts
· 65 kts
85 kts
140 kts
90 kts
85 kts
11 kts
95 kts
ENGINE FAILURE DURING GROUND ROLL
1. Throttles - IDLE
2. Braking - MAXIMUM
3. Fuel Selectors - OFF
4. Battery, Alternator, and Magneto/Start Switches - OFF
ENGINE FAILURE AFTER LIFTOFF AND IN FLIGHT
1. Landing Gear and Flaps ~ UP
2. Throttle (inoperative engine) - IDLE
3. Propeller (inoperative engine) - FEATHER
4. Power (operative engine) - AS REQUIRED
5. Airspeed -AT OR ABOVE THE 50-FT TAKE-OFF SPEED (80
KNOTS)
6. After positive control of the airplane is established:
7. Secure inoperative engine:
a.. Mixture Control - IDLE CUT-OFF
b. Fuel Selector - OFF
c. Aux Fuel Pump - OFF
d. Magneto/Start Switch - OFF
e. Alternator Switch - OFF
f. Cowl Flap - CLOSE
8. Airspeed - ESTABLISH 85 KTS
9. Electrical load - MONITOR
4
E
M
E
R
G
E
N
C
Y
P
R
O
C
E
D
U
R
E
S
E AIR START
M WITH UNFEATHERING ACCUMULA TORS:
1 . Fuel Selector - ON
E
2. Throttle - SET approximately ¼ in travel
R
3. Aux Fuel Pump - ON
G
4. Magneto/Start Switch - BOTH
E
5. Propeller Control - MOVE FULL FORWARD UNTIL ENGINE
N
WINDMILLS, THEN BACK TO MIDRANGE. USE STARTER
MOMENTARILY IF AIRSPIEED IS BELOW 100 KTS.
C
6. Mixture - FULL RICH
Y
ENGINE FIRE (GROUND)
1. Mixture Controls - IDLE CUT-OFF
2. Continue to crank affected engine
3. Fuel Selectors - OFF
4. Battery and Alternator Switches - OFF
5. Extinguish fire with extinguisher
ENGINE FIRE IN FLIGHT
1. Shut down the affected engine according to the. following procedure
and land immediately. Follow the applicable single-engine procedures in
this section.
2. Fuel Selector - OFF
3. Mixture Control - IDLE CUT-OFF
4. Propeller -FEATHER
5. Aux Fuel Pump - OFF
6. Magneto/Start Switch - OFF
7. Alternator Switch - OFF
7. If engine fails to run, clear engine by allowing it to windmill with
mixture in the FULL LEAN position.
8. When engine fires, advance mixture to FULL RICH.
9. When Engine Starts ADJUST THROTTLE , PROPELLER, AND
MIXTURE CONTROLS
10. Aux Fuel Pump - OFF (when reliable power has been regained)
11. Alternator Switch ON
12. Oil Pressure and Oil Temperature .. CHECK
13. Warm Up Engine (approximately 2000 rpm and 15 in. HG)
14. Set power as required and trim.
P
R
O
C
E
D
U
R
E
S WITHOUT UNFEA THERING ACCUMULA TORS:
EMERGENCY DESCENT
1 . Propellers - 2700 RPM
2. Throttles - IDLE
3. Airspeed - 140 KTS
4. Landing Gear - DOWN
1. Fuel Selector - ON
2. Throttle: SET approximately V4 travel
3. Aux Fuel Pump - ON
4. Magneto/Start Switch - BOTH
5. Mixture - FULL RICH
6. Propeller Control & MOVE FORWARD OF FEATHERING
DETENT TO MIDRANGE
7. Magneto/Start Switch - START and PUSH TO PRIME
8. When Engine Starts - ADJUST THROTTLE, PROPELLER, AND
MIXTURE CONTROLS
9. Aux Fuel Pump - OFF (when reliable power has been regained)
10. Alternator Switch - ON
11. Oil Pressure and Oil Temperature -CHECK
12. Warm Up Engine (approximately 2000 rpm and 15 in. Hg)
13. Set power as required and trim.
MAXIMUM GLIDE CONFIGURATION
1. Propellers - FEATHER
2. Wing Flaps - UP
3. Landing Gear - UP
4. Cowl Flaps - CLOSE
5. Airspeed - 95 KTS
The glide ratio in this configuration is approximately 2 nautical miles of
gliding distance for each 1000 feet of altitude above the terrain.
LANDING EMERGENCIES
GEAR-UP LANDING
1. Cowl Flaps - CLOSE
2. Wing Flaps ~ FULL DOWN (ON)
3. Throttles. - IDLE
4. Mixture Controls - IDLE CUT-OFF
5. Battery, Alternator, and Magneto/Start Switches - OFF
6. Fuel Selectors - OFF
7. Keep wings level during touchdown.
8. Get clear of the airplane as soon as possible after it stops.
5
E
M
E
R
G
E
N
C
Y
P
R
O
C
E
D
U
R
E
S
ONE-ENGINE-INOPERATIVE LANDING
COMPLETE LOSS OF ELECTRICAL POWER INDICATIONS
1. Both Alternator Switches - OFF
2. Battery Switch - OFF
3. Both BUS-ISO Circuit Breakers -PULL
4. Remove all electrical loads.
5. Both Alternator Switches - ON.
6. Minimize all electrical loads. Select only that electrical equipment
which is essential for safe flight.
7, Extend landing gear with emergency system.
8. LAND AS SOON AS PRACTICAL; HAVE THE COMPLETE
ELECTRICAL SYSTEM CHECKED BEFORE THE NEXT FLIGHT.
E On final approach and when it is certain that the field can be reached:
1 . Landing Gear ~ DOWN
M
2. Airspeed - 85 KTS
E
3. Power - AS REQUIRED
R
4. When it is certain there is no possibility of go-around: Wing Flaps G
FULL DOWN (DN)
E
5. Execute normal landing.
N
C ONE-ENGINE-INOPERATIVE GO-AROUND
Y
1. Power - MAXIMUM ALLOWABLE
2. Landing Gear - UP
3. Wing Flaps - UP
P
4. Airspeed - MAINTAIN 85 KTS MINIMUM
R
O
C OPERATION ON CROSSFEED
E Left Engine Inoperative:
1. Right Aux Fuel Pump - ON
D
2. Left Fuel Selector ~ OFF
U
3. Right Fuel Selector - CROSS FEED
R
4. Right Aux Fuel Pump - ON or OFF as required
E
S Right Engine Inoperative:
ILLUMINATION OF ALTERNATOR-OUT LIGHT
1. Check the respective loadmeter for load indication:
2. No load - Turn off affected alternator.
3. Reduce load to single alternator capability.
4. Reset the affected alternator with the alternator switch. Monitor over
voltage and under voltage lights and loadmeter for proper operation.
ALTERNA TOR-OUT UNDERVOLTAGE lights Of both
ALTERNATOR-OUT OVERVOLTAGE lights:
1. Check loadmeters for load indication. If condition indicates
malfunction of both alternator circuits:
2. Both ALT Switches - OFF
3. Minimize electrical load since only battery power will be available.
4. Reset the alternators with the alternator switches.
5. Monitor over voltage and under voltage lights and loadmeters for
proper operation.
1. Left Aux Fuel Pump - ON
2. Right Fuel Selector - OFF
3. Left Fuel Selector -CROSS FEED
4. Left Aux Fuel Pump - ON or OFF as required
ELECTRICAL SMOKE OR FIRE
Action to be taken must consider existing conditions and (1quipment installed:
1 . Battery and Alternator Switches - OFF
WARNING Electrically driven instruments and stall warning horn will
become inoperative.
2. All Electrical Switches - OFF
3. Battery and Alternator Switches - ON
4. Essential Electrical Equipment· ON (Isolate defective equipment)
STARTER ENGAGED WARNING LIGHT ILLUMINATED (If installed)
Illuminated On the Ground:
1. Battery and Alternator Switches ~ OFF
2, Do not take off
Illuminated In Flight After Air Start:
1, Perform action for COMPLETE LOSS OF ELECTRICAL POWER
2, land as soon as practical
6
E
M
E
R
G
E
N
C
Y
P
R
O
C
E
D
U
R
E
S
E
M
E
R
G
E
N
C
Y
P
R
O
C
E
D
U
R
E
S
UNSCHEDULED ELECTRIC ELEVATOR TRIM
1. Airplane Attitude - MAINTAIN using elevator control.
2. Elevator Trim Thumb Switch (on/control wheel) DEPRESS .AND
MOVE IN DIRECTION OPPOSITE UNSCHEDULED PITCH TRIM.
3. Elevator Trim ON-OFF Switch (on instrument panel) OFF
4. Manual Elevator Trim Control Wheel - RETRIM AS DESIRED
LANDING GEAR MANUAL EXTENSION
Reduce airspeed before attempting manual extension of the landing gear.
1. Landing GEAR MOTOR Circuit Breaker - OFF (pull out)
2. Landing Gear Switch Handle - DOWN position
3. Airspeed - 100 KTS MAXIMUM
4. Emergency Extension Valve - OPEN (Use Emergency Extension
Wrench ~ Turn Counterclockwise)
LANDING GEAR RETRACTION AFTER PRACTICE MANUAL
EXTENSION
1 . Emergency Extension Valve· CLOSE (Use Emergency Extension
Wrench - Turn Clockwise)
2. Landing GEAR MOTOR Circuit Breaker - ON (push in)
3. Landing Gear Switch Handle - UP
ALTERNATE STATIC AIR SOURCE
1. Pilot's Alternate Static Air Source - Switch to ON ALTERNATE
(lower sidewall adjacent to pilot)
2. For Airspeed Calibration and Altimeter Correction, refer to
PERFORMANCE section.
SIMULATED ONE-ENGINE INOPERATIVE ZERO THRUST
1. Throttle Lever - SET 8.0 in. Hg MANIFOLD PRESSURE
2. Propeller lever - RETARD TO FEATHER DETENT
UNLATCHED DOOR IN FLIGHT
If the cabin door is not secured it may come unlatched in flight This usually
occurs during or just after takeoff. The door will trail in a position
approximately 3 inches open. A buffet may be encountered with the door
open in flight Return to the field in a normal manner. If practicable, during
the landing flare-out have a passenger hold the door to prevent it from
swinging open.
7
Articles Pertaining to Multi-engine Flight
1
* Always Leave Yourself An Out
While single-engine aircraft may not be safer, twins can be more dangerous
Richard N. Aarons (From the FAA's Accident Prevention Program, FAA-P-8740-25, AFO-800-1079)
Despite heated scolding’s from flight instructors and grim warnings from the National Transportation Safety
Board, many pilots still seem to believe that implied in the fact that an aircraft has two engines is a promise
that it will perform with only one of those engines operative. And the light-twin stall/spin accident rate further
indicates that many multiengine pilots have not come to grips with the facts that II/Significantly more than half
the climb performance disappears when one engine signs out, and 2/ Exploration of the Vmc regime close to
the ground is a sure way to kill yourself.
A while back, the NTSB reported that light multi-engine aircraft are involved in fewer engine-failure-related
accidents than single-engine aircraft. However the same report observed that an engine-failure-related accident
in a twin is four times more likely to cause serious or fatal injuries. An analysis of that report appeared in the
June issue of B/CA (Cause and Circumstance).
This article is not intended to debate the relative merits of twins versus singles. The twin offers obvious safety
advantages over the single, especially in the enroute phase, and if, only if, the pilot fully understands the real
options offered by that second engine in the takeoff and approach phases as well.
Takeoff is the most critical time for a light-twin pilot, but if something goes wrong he may have the option of
continued flight, an option denied his single-engine counterpart. More often than not that second engine will
provide only a little more time to pick a soft spot. (This assumes that the engine is lost before the aircraft
reaches maneuvering altitude of 300 to 500 feet.) But even those few extra seconds, representing a few
hundred extra yards, can give the twin pilot a hell of a safety advantage over his single-engine counterpart. But
I must stress again, this safety advantage exists only if the multi-engine pilot fully understands his machine.
In this article we're going to explore some of the design concepts and certification procedures applicable to
current-production light twins and then take a look at light-twin performance tables and attempt to find ways
of getting more realistic information out of them. Along the way, we'll establish five rules for technique. We
use these rules at B/CA, pilots at the FAA Academy use them, and we're sure many readers are aware of them,
but we'll throw them in anyway in hopes of picking up a few more converts.
Let's look first at the implied promise that a general-aviation twin will perform with one engine inoperative.
Part 23 sets standards for the certification of light aircraft weighing 12,500 pounds or less. Multi-engine
aircraft are further divided by Part 23 into two weight classes, split at 6,000 pounds with the group that weighs
6,000 pounds or less, subdivided into two, depending on Vso (stall speed in the landing configuration). The
break comes at 61 knots CAS.
Only those twins that weigh more than 6,000 pounds or have a Vso higher than 61 knots need to demonstrate
any single-engine climb performance at all for certification. And the requirement is pretty meager. Basically,
the regulation says that these aircraft must demonstrate a single-engine climb capability at 5,000 feet (ISA)
with the inoperative engine feathered and the aircraft in a clean configuration. The amount of climb
performance required is determined by the formula ROC=0.027 Vsol. The Rockwell Commander 500S
(Shrike), for example, weighs over 6,000 pounds and therefore must meet this climb requirement. Vso for the
Shrike is 63 knots, thus its minimum single-engine climb performance at 5,000 feet is 0.027 x 631 or 107.16
fpm. The Shrike's actual single-engine climb at 5,000 feet is 129 fpm, so the manufacturer bettered the Part 23
requirement, but not by much.
The Cessna 310 weighs less than 6,000 pounds, but stalls at 63.9 knots, so it too must meet the enroute singleengine climb standards. Plugging 63.9 knots into the 0.027 VS02 equation produces a requirement of 110.2
fpm. The 310's actual single-engine climb under Part 23 conditions is 119 fpm.
2
The Aztec, like the 310, weighs less than 6,000 pounds, but it slips under the Vso wire with a stall speed if
60.8 knots. The only requirement that an airplane in this group must meet is that its single-engine climb
performance at 5,000 feet (positive or negative) be determined. The Aztec climbs at 50 fpm on one engine at
that altitude, but the regulation doesn't require that it climb at all at that or any other altitude.
We can see then that where an enroute single-engine climb is required, it's minimal. Consider a hypothetical
aircraft with an outrageous Vso of 100 knots CAS. The FAA requires only that such an aircraft demonstrate a
paltry climb of 270 fpm on one engine at 5,000 feet.
There's another point to consider here. The FAA does not require continued single-engine takeoff capability
for any light aircraft other than those designed for air-taxi work and capable of hauling 10 or more passengers.
Stated another way, there is no reason to assume that an aircraft will exhibit positive single-engine
performance in the takeoff configuration at sea level just because it had to meet a single-engine climbperformance requirement at 5,000 clean.
FAA Academy flight instructors are fully aware of this situation and believe it's important to stress it with the
agency's GAIDO inspectors. An in-house white paper on light twins used at training courses for FAA pilots
puts it this way:
"There is nothing in the FAR governing the certification of light multi-engine aircraft which says they must fly
(maintain altitude) while in the takeoff configuration and with an engine inoperative. In fact, many of the light
twins are not required to do this with one engine inoperative in any configuration, even at sea level…. With
regard to performance (but not controllability) in the takeoff or landing configuration, the light multi-engine
aircraft is, in concept, merely a single-engine aircraft with its power divided into two or more individual
packages." (Emphasis ours.)
While this concept of not putting all your eggs in one basket leads to certain advantages, it also leads to
disadvantages should the eggs in one basket get broken.
You'll remember from your multi-engine transition training that the flight instructor and check pilot repeatedly
insisted that when you lose one engine on a twin, performance is not halved, but actually reduced by 80
percent or more.
That 80-percent performance-loss figure is not just a number pulled out of the air for emphasis. It's easy to
figure for any aircraft. Consider the Beech Baron B55 which has an all-engine climb rate (sea level, standard
conditions, max gross weight) of 1,670 fpm and a single-engine climb rate under the same conditions of 318
fpm. The loss of climb performance in this case is
100-(318/1,670 x 100)
or 80.96 percent. The climb performance remaining after the loss of one engine on the B55 is 19.04 percent.
Performance loss for the cabin twins, turboprops and business jets is similar. The Rockwell Commander 685,
for example, loses 83.42 percent of its climb performance when one engine quits; the Swearingen Merlin III
loses 75.49 and the Learjet 25C 71.07. The Lockheed JetStar loses 43.48 percent if its climb performance with
the loss of one engine, but remember, it has four engines. The loss of one quarter of its thrust results in a loss
of almost half its climb performance and if it were to lose half its thrust, climb performance would be cut by
more than 75 percent. (The table on this page shows similar performance changes for other aircraft.)
Some turboprops and all turbojets demonstrate a continued takeoff capability with one engine inoperative. The
turbojets do so because of the tougher certification requirements of FAR Part 25. Although loss of power in
terms of percentage reduction is similar in all categories of business aircraft, the turbojets and some turboprops
3
have much better single-engine performance because they're starting with higher numbers. While the Learjet
25C, for example, loses more than 71 percent of its climb performance when one engine is shut down, it
begins with an all-engine rate of climb of 6,050 fpm. When this is reduced by 71 percent, It still climbs at
1,750, which Is much better performance than you get out of many light-piston twins with both engines
running.
Why the performance loss is greater than 50 percent with the failure of one engine needs a bit of explanation.
Climb performance is a function of thrust horsepower (or simply thrust in turbojets) which is in excess of that
required for straight and level flight. You can convince yourself that this is the case by trimming your aircraft
for straight and level at its best all-engine rate-of-climb speed and checking the power setting. If you ease the
stick back at this point, the airplane will not settle into a sustained climb. After a momentary climb it may, in
fact, begin to descend. However, if you go back to straight and level flight at the best-rate-of-climb speed and
slowly feed in power as you maintain airspeed, a climb will be indicated, and the rate of climb will depend on
the power you add-which is power in excess of that required for straight and level.
Now trim for straight and level (in the clean configuration at about 1,500 feet) at the best single-engine rate-ofclimb speed, adjust one engine to its zero-thrust setting (about 10 inches to simulate feather). You'll notice that
the "good" engine, now carrying the full burden, is producing 75-percent power or more. If you increase the
power on the good engine, your aircraft will begin a climb, but at a very modest rate. This is so because you've
got much less "excess" horsepower available. If you are interested in the math behind this, an approximate
formula for rate of climb is:
R/C = ehp x 33,000/weight(ehp is thrust horsepower In excess of that required for straight and level.) To
determine ehp, rearrange the formula to read:
EHP = R/C x weight/33,000
Using the Seneca as an example, with its maximum gross weight of 4,200 pounds and all-engine and singleengine climb rates of 1,860 and 190 fpm respectively, we find that this aircraft has about 236 thrust
horsepower available for climb with both powerplants operating and only 24 excess thrust horsepower for
climb on one engine. If you refer to the climb-performance-loss formula, you'll see that the Seneca loses about
89.78 percent of its climb performance when an engine stops:
100 - 190/1,860 x 100 = 89.78
If you examine the two figures above for excess horsepower and state them in terms of percentages, you'll see
that an engine loss in the Seneca represents a loss of 89.83 percent of thrust horsepower available for climb.
Part 23 defines Vmc as "the minimum calibrated airspeed at which, when any engine is suddenly made
inoperative, it is possible to recover control of the airplane with that engine still inoperative, and maintain
straight flight, either with zero yaw, or, at the option of the manufacturer, with an angle of bank of not more
than five degrees." Vmc may not be higher than 1.2 times the stall speed with flaps in takeoff position and the
gear retracted. In flight-test work, Vmc is determined with takeoff or METO power on each engine, the
rearmost allowable center of gravity, flaps in takeoff position, landing gear retracted and the propeller of the
inoperative engine 1/ Windmilling with the propeller set in the takeoff range, or 2/ Feathered, if the airplane
has an automatic feathering device. During recovery, the airplane may not assume any dangerous attitude or
require exceptional piloting skill, alertness, or strength to prevent a heading change of more than 20 degrees.
Vmc is not at all mysterious. It's simply that speed at which airflow past the rudder is reduced to such an extent
that rudder forces cannot overcome the asymmetrical forces caused by takeoff power on one side and a
windmilling prop on the other.
4
When that speed is reached and the nose starts to swing toward the inoperative engine, the only hope of
regaining control is to reduce thrust on the good engine (or increase speed). An increase in airspeed requires a
change in momentum and thus a certain period of time to become effective. Thus, for practical purposes, the
only method of regaining control is to reduce power on the operating engine quickly.
Performance Loss of Representative Twins with One Engine Out
Pistons
Beech Baron 58
Beech Duke
Beech Queen Air
Cessna 310
Cessna 340
Cessna 402B
Cessna 421B
Piper Aztec
Piper Navajo Chieftain
Piper Pressurized Navajo
Piper Seneca
Turboprops
Beech King Air 90
Mitsubishi MU2-J
Rockwell Commander 690A
Swearingen Merlin III
Business Jets
Cessna Citation
Falcon F
Falcon 10
Gates Learjet 24D
Grumman Gulfstream II
Hawker Siddeley HS 125-600
IAI 1123 Westwind
Rockwell Sabre 75A
All engine climb (fpm)
1,694
1,601
1,275
1,495
1,500
1,610
1,850
1,490
1,390
1,740
1,860
S.E. climb Loss (fpm)
382
307
210
327
250
225
305
240
230
240
190
Percent
80.70
80.82
83.53
78.13
83.33
86.02
83.51
83.89
83.45
86.21
89.78
All engine climb (fpm)
1,870
2,690
2,849
2,530
S.E. climb Loss (fpm)
470
845
893
620
Percent
74.87
68.59
68.66
75.49
All engine climb (fpm)
3,100
3,300
6,000
6,800
4,350
3,550
4,040
4,300
S.E. climb Loss (fpm)
800
800
1,500
2,100
1,525
663
1,100
1,100
Percent
74.19
75.76
75.00
69.12
64.94
81.32
72.77
74.42
Vmc is not a static number like flap-operating speed or the never-exceed speed. It changes with conditions.
The Part 23 test described above cites the worst conditions. Aft cg, for example, reduces the force of the
rudder because it shortens the arm and thus the turning moment. Vmc will be lower with forward cg and all
other factors being equal. Conversely if the aircraft is loaded slightly out of rear cg, Vmc will be higher. In
normally aspirated aircraft Vmc decreases with an increase in density altitude primarily because the output of
the operating engine decreases, thus the asymmetrical power situation decreases.
At first glance, this situation seems to be a good one. The hotter and higher the airport, the lower Vmc. But
actually nothing about Vmc is good and there's a hell of a catch in it. As Vmc decreases (with a decrease in
good-engine performance) it approaches the stall speed. This is especially bad news for flight instructors who
must purposely explore the Vmc regime with their students. If Vmc and stall are reached simultaneously, a
spin is almost inevitable and Part 23 twins are often impossible to get out of a spin. (One northeast flight
school lost two aircraft in one summer because of this problem.)
5
Landing-gear extension seems to reduce Vmc for most light twins and this, like the density altitude situation,
can be both good and bad.
Suppose a pilot gets himself in the unhappy situation of being 50 feet in the air, gear down, with one engine
out, full power on the good side and full rudder to keep the nose from swinging. He doesn't like the look of the
trees in front of him so he decides to make a go for it. He reaches down and retracts the gear to get rid of its
drag, hoping that will enable the aircraft to accelerate to a climb speed. Suddenly he's looking at the trees
through the top of the windshield. Why? Because he was on the edge of Vmc and sucked up the gear, which
increased Vmc costing him control of the aircraft.
The prudent light-twin pilot, of course, would never find himself in that situation because he would know
beforehand that his hopes of accelerating without altitude loss from Vmc to Vxse or Vyse are practically nil.
If your aircraft is relatively new, Vmc, as determined by the Part 23 certification test, is marked by a red line
on the airspeed-indicator face. Indicated Vmc will never be higher than this line, so the slash can be used as a
guide to keep you out of trouble. This does not mean that the airplane will spin out as soon as the line is
reached. Under the circumstances described above (such as high density altitude) controlled flight with full
power on the operative engine is possible when the indicated airspeed falls below the red line, but it certainly
isn't advisable. Exploring this part of the flight envelope in an actual emergency can (and probably will) kill
you. So let's establish our first rule for multi-engine flying.
Rule #1 — Never allow the airspeed to drop below published Vmc except during the last few yards of the
landing flare, and then only if the field If extremely short.
Some aircraft have an all-engine best-angle-of-climb speed (Vx) below Vmc. Using that climb speed under
any circumstances can be extremely dangerous. The instructors at the FAA Academy have this to say about the
use of Vx near the ground: "Trying to gain height too fast after takeoff can be dangerous because of control
problems. If the airplane is in the air below Vmc when an engine fails, the pilot might avoid a crash by rapidly
retarding the throttles, although the odds are not in favor of the pilot." Thus we have another rule:
Rule #2 — A best all-engine angle-of-climb speed that is lower than Vmc is an emergency speed and should
be used near the ground only if you're willing to bet your life that one engine won't quit during the climb.
Manufacturers differ on the proper takeoff speed for a light twin. Piper, for example, recommends that most of
its twins be rotated at Vmc. Cessna, on the other hand, suggests liftoff at a speed much higher than Vmc and
very close to best single-engine angle-of-climb speed. In the case of the Cessna 310, Vmc is 75 knots,
recommended rotation speed is 91 knots and best single-engine angle-of-climb speed is 94.
It's important to note that manufacturers who recommended liftoff at or near Vmc do not, as a rule, show
figures for continued takeoff in event of an engine failure at the liftoff speed. The reason is simple. Most Part
23 twins cannot accelerate in the takeoff configuration from Vmc to best single-engine rate-of-climb speed
while maintaining a positive climb rule. Conversely it is possible to accelerate them (under near sea-level
conditions) from best single-engine angle-of-climb speed to best single-engine rate-of-climb speed while
maintaining a positive, though meager, climb. Manufacturers who recommended liftoff well above Vmc
usually show continued single-engine takeoff performance in their owners or flight manuals.
6
Engine-Out Angle of Climb
(degrees, at best-rate speed)
ISA
ISA + 20
Piper Seneca
Cessna Skymaster
Piper Turbo Aztec
Cessna 402B
Piper Navajo
Cessna 340
Cessna 421
Rockwell International 685
Piper Navajo P
Mitsubishi MU2-K
King Air A100
1.2
1.7
1.6
1.2
1.5
1.4
1.6
1.2
1.2
4.2
2.1
0.6
1.3
1.5
0.6
1.1
0.8
1.0
0.7
1.0
2.4
1.0
NOTE: For comparison purposes, the average two engine rate of climb for the above aircraft is 8 degrees.
We have to recommend against lifting off at Vmc for the same reason most flight instructors recommend
against "stalling" a single-engine aircraft off the ground. In the latter case, the single will fly to the edge of
ground effect but could reach that point behind the power curve. An engine failure at that point could result in
a stall and pitch over. In the case of the twin, an engine failure at liftoff at Vmc could produce such a rapid
turning moment that control would be lost immediately. The FAA says, "Experience has shown that an
unexpected engine failure surprises the pilot so that he will act as though he is swimming in glue." If a pilot
rotates at Vmc, loses an engine and begins the "swimming in glue" routine, his odds of survival are minimal.
The alternative, of course, is to hold the aircraft on the ground a little longer. Most multi-engine instructors
believe that Vmc-plus-five knots is a good compromise for use in those aircraft with a- recommended liftoff at
Vmc. Why not hold it down until almost reaching best single-engine angle-of-climb speed like the Cessna
folks recommend? The reason again is controllability. Cessna light twins and most cabin twins of all
manufacturers are designed to stay on the ground well beyond Vmc. But some of the light twins simply are
not. For example, we've tried holding the Seneca and Aztec on the runway beyond Vmc-plus-five knots and
have discovered that both aircraft begin to wheelbarrow. (Tests were at maximum gross weight, zero flaps.)
High-speed wheelbarrowing can be just as dangerous as liftoff too close to Vmc, especially when we're talking
about selecting an appropriate speed for every takeoff. Remember too that the takeoff-performance figures in
the aircraft-owners or flight manual are invalid as soon as we use techniques different from those specified in
the table footnotes. (More on this later.) Anyway, we've got a third rule now for light-twin operation:
Rule #3 — Use the manufacturer's recommended liftoff speed or Vmc plus five knots whichever is greater.
Now that we're in the air, the first priority is to accelerate the aircraft to best single-engine angle-of-climb
speed (if we're not already there), then best single-engine rate-of-climb speed and finally best all-engine rateof-climb speed. Each of these speeds is a milestone in the takeoff and the realization of each reduces the
decisions to be made in the event of an engine failure.
Many instructors recommended that best single-engine rate-of-climb speed (the blue line if it's marked on your
airspeed indicator) be used for the initial climb to a safe maneuvering altitude. B/CA's pilots recommended the
best all-engine rate-of-climb speed, when it is faster (it normally is), for two reasons. First, the swimming-inglue syndrome is going to translate into speed lost. So if an engine does quit while you're holding best allengine rate-of-climb speed, the deceleration while you're getting things straightened out will probably put you
pretty close to best single-engine rate-of-climb speed which is where you want to be anyway. Second, the best
all-engine rate speed will get you to maneuvering altitude and out of immediate danger.
7
One caution here is important. Avoid climbing to maneuvering altitude at a speed greater than best all-engine
rate of climb-to do so is sloppy and inefficient. Here's why:
As we have seen, climb is a function of thrust horsepower in excess of that required for straight and level flight
and drag increases as the square of the speed. At the same time, power required to maintain a velocity
increases as the cube of the velocity.
The Cessna 421 has a best all-engine rate-of-climb speed of 110 knots, which produces a climb of 1,850 fpm
at sea level. If the aircraft is climbing at 122 knots, drag would increase by 1.2 times and the power required to
maintain that velocity would increase 1.4 times with a resulting decrease of excess thrust horsepower available
for climb. In this example the climb rate decreases to about 1,261 fpm; thus a 10-percent increase in speed
over the best-rate speed produces a 32-percent decrease in climb performance. These exercises produce
another rule:
Rule #4 — After leaving the ground above Vmc, climb not slower than single-engine best rate-of-climb speed
and not faster than best all-engine rate of speed. The latter speed is preferable if obstacles are not a
consideration.
You may have gotten the impression by now that we're picking on Cessna and Piper in our examples. Piper
twins and the Rockwell Commander 500S have shown up in our examples here because the Ziff-Davis
Aviation Division operates (or operated in the case of the Shrike) these aircraft and our observations
concerning them were gained from extensive first-hand knowledge. The Cessna twins are used as examples
because Cessna, in our opinion, produces the best owners manuals in the industry. This is not to say that the
Cessna manuals can't be improved-they are merely the best of a very poor lot. But in any event Cessna
manuals provide most of the information a pilot needs to plan for emergencies. At this writing, a special
committee of the General Aviation Manufacturer's Association is working on standardization and
improvement of light-aircraft flight manuals. But until such time as the GAMA committee and the FAA
improve the situation, we're stuck with the paper work that comes with the airplane. Here comes rule five:
Rule #5 — Be a skeptic when reading the performance tables in your Part 23 aircraft-owners manual and be
doubly sure you read the fine print. Add plenty of fudge factors.
You'll notice first when you look at light-twin takeoff-performance tables (in anybody's manual) that the
takeoff is initiated after power has been run to maximum with the brakes locked and the mixtures adjusted to
optimum settings. We've attempted to measure the difference in the takeoff roll for brakes held versus a
normal throttles-up-smooth start and have come up with figures ranging from an extra 200 to 400 feet.
Remember that these figures will increase in density altitude.
If the book figures for continued single-engine takeoff and accelerate/stop distances, you've really got it made,
because now, by adding a few hundred feet here and there to compensate for real-time situations, you can get a
good handle on what's going to happen if one quits-and what you're going to do about it.
We'll use a Cessna 421 for this exercise and remind you again that we're not picking on the 421. It's just that
Cessna is honest enough to try to tell it like it is in its owners manuals.
On a standard day at 7,450 pounds, a 421 needs 2,500 feet to get off and over a 50-foot obstacle. This assumes
a rotate speed of 106 knots, well above Vmc. If an engine is lost at rotation and the pilot elects to go anyway,
he'll need a total of 5,000 feet to clear the obstacle. The ground run in both cases is about 2,000 feet. In the
case of both engines operating, the climb from rotation to 50 feet requires a horizontal distance of only 500
feet; but in the case of the single-engine takeoff, the climb to 50 feet requires a horizontal distance of 3,000
8
feet, a six-fold increase. And keep in mind that we're still only 50 feet above ground and that to get this far
we've made split-second decisions all along the way.
Let's get some real-life factors into the single-engine takeoff equation. Suppose, as is usually the case, we
begin the takeoff roll about 75 feet from the approach end of the runway and do so without holding the brakes.
This could add 475 feet to the handbook figure. Next, suppose we lose the engine at rotation, but it takes us
three seconds to recognize the situation and react. (This, by the way, is a very conservative figure.) The
reaction time will cost us about 537 feet. Now the total horizontal distance from the beginning of the runway
to a point at which the aircraft is 50 feet above the surface (assuming engine loss at rotation) is 6,012 feet, an
increase of 20 percent. The 421's sea-level, single-engine climb rate is about 305 fpm. Assuming that we want
to get at least 500 feet under us before trying anything fancy like returning for a landing, we must continue
more or less straight ahead for one minute and 28 seconds. This climb will cover a horizontal distance of some
16,485 feet bringing the total distance covered from the rotation point to 19,485 feet, or 3.7 miles.
If all this happens at a sea-level airport on a hot day (ISA plus 20 degrees C.), we will not reach the 50-foot
level until the aircraft has covered a horizontal distance of 7,040 feet from the point of rotation and engine
failure. Assuming calm air the aircraft will reach 500 feet some 5.9 miles from the rotation point or 6.6 miles
from the runway beginning. If the hot condition brought convective turbulence with it, the effective climb rate
would be reduced by 100 fpm. Under these conditions, the aircraft would reach 500 feet some 9.9 miles from
the rotation point and 10.6 miles from the runway beginning.
I've been stating these horizontal distances in terms of miles to stress a point. If your flight manual gives
figures for continued single-engine takeoff, make sure you look at the climb performance beyond the 50-foot
altitude to be certain that continued takeoff is a viable alternative if an engine quits. You might be able to live
with that 10.6-mile hot-day figure on a departure from JFK where you could head out over the Atlantic, but the
same departure from Teterboro would make collision with obstacles almost a certainty. In the case of the
Teterboro departure, a rejected takeoff within the boundaries of the airport or stuffing it into the first available
parking lot might be your only survivable alternative. You certainly aren't going to survive if you run into
something, or fall out of the air trying to get performance from the aircraft that the manufacturer never built
into it.
So, on the subject of rejected takeoffs, check the accelerate/stop tables and the landing-distance charts before
each takeoff. Remember to add 500 feet or so to the accelerate/stop distance to compensate for the runway left
behind you when you moved into position and the rolling (rather than brakes-held) ground run; add another
500 feet or so for your reaction time and then another 200 feet for "technique." Part 23 sets no standards for
the determination of accelerate/ stop distances in light twins. The stopping distances are often determined by a
10,000-hour test pilot who does everything short of retracting the gear to stop the aircraft. Even in an
emergency situation, you're probably not going to get the same stopping performance he does. (Remember to
get the flaps up to increase the weight on the wheels.)
If you're lucky enough to have normal takeoff, single-engine takeoff and accelerate/stop tables in your airplane
manual, another check you should make before takeoff is the total distance (adding our real-life factors, of
course) for takeoff with both engines operating, climb to 50 feet, then to land from that 50-foot altitude and
bring the aircraft to a complete stop. This figure for the 421 (adding all our fudge factors) comes to 5,689 feet.
This is less than the distance required (6,012 feet) to climb to 50 feet assuming an engine loss at rotation under
the same conditions.
Knowing this number gives you another alternative. If you have 5,700 feet of runway and overrun, you might
decide to put the aircraft back on the runway even if the engine failure occurs well after takeoff as you're going
through 50 feet. Even if you don't have the full 5,700 feet, you may have enough runway to get the wheels
back on the hard surface and begin some serious braking before you run off the end of the runway. B/CA's
9
philosophy, which was copied from that of the flight department of a major manufacturer of light twins, is that
it's always better to go through the fence at 50 knots than to hit the trees at 120.
To the best of my knowledge, a takeoff to 50 feet followed by an immediate landing is not taught in twins,
although a similar maneuver is taught in single-engine aircraft. It should be, but before you go out and try it,
take your aircraft to altitude and practice the transition from climbing flight to gliding flight until you can
make the transition without significant loss of airspeed. And it might be a good idea to take an instructor
along. If you decide to try it on a runway allow a good 8,000 to 10,000 feet for the first few attempts-and take
your time.
If your aircraft-owners manual does not show performance figures for continued singleengine takeoff, chances are that the airplane simply is not capable of accelerating from liftoff speed to a
reasonable climb speed in the takeoff configuration. In this case, your decisions are pretty limited. You really
don't have a go-situation until the aircraft is cleaned up and has reached at least best single-engine angle-ofclimb speed. An engine failure before that time (on the ground or in the air) dictates an immediate controlled
descent to a landing. The surviving engine, in this case, can be used to help maneuver to a suitable (nearby)
landing place if all of the runway is gone.
You can calculate your own accelerate/stop distances by running the aircraft up to takeoff speed and then
bringing it to a stop. (Make sure you start these tests on a good long runway). Do this several times at max
gross weight counting runway lights (the airport operator can tell you the distance between lights) and you'll
get a good ball-park figure for accelerate/stop. Then use that figure in your future takeoff planning.
To sum it up, we've seen that:
 The loss of an engine on a Part 23 twin will decrease sea-level climb performance by at least 80
percent and can decrease it by as much as 90 percent.
 There is no requirement for continued single-engine takeoff capability for Part 23 twins, nor, in fact, is
there a requirement for any positive single-engine climb at all for twins which weigh less than 6,000
pounds and have a stall speed of 61 knots or less in the landing configuration.
 It is vital to know all you can about your aircraft's performance in normal and emergency situations
before the takeoff is attempted. To arrive at reasonable performance predictions you must adjust the
information provided by the manufacturer to take into account real-life factors such as reaction time,
runway condition and obstacles, including obstacles five or more miles beyond the airport boundary.
 A well-executed Part 23-twin takeoff is one in which the aircraft leaves the ground at least at Vmcplus-five knots and climbs at a speed of at least Vxse and not more than Vy.
One final comment should be made on the single-engine takeoff. Your personal IFR takeoff minimums should
include factors for an engine failure. Certainly your go-no go decision with an engine failure immediately after
rotation or in the initial climb segment is strongly affected by weather. Consider the case of the 421 we
discussed above which, in the event of engine failure at rotation, requires about 10.6 miles on a hot day from
the start of the runway to a point where maneuvering altitude (500 feet) is reached. Poor visibility and low
ceilings could make that situation almost hopeless in any but the most sparsely built-up areas.
Single-engine landings, as you'll remember from your check rides, are not difficult at all. Single-engine goarounds in Part 23 twins are, on the other hand, damn near impossible unless they are begun from an altitude
several hundred feet above the terrain and at an airspeed at or slightly above the best single-engine rate-ofclimb speed. The situation is doubly bad if you start a go-around and then lose an engine. If you want proof, go
to altitude and set up a 500 fpm rate of descent at a speed 10 percent below the best single-engine rate-ofclimb speed. Continue the descent until you are within 200 feet of a cardinal altitude, then simulate a singleengine go-around. Attempt to clean up the airplane, and accelerate to best single-engine climb speed without
sinking through the cardinal altitude. It can't be done with Part 23 twins-we've tried it in just about everything
10
from the Seneca to the King Air A100. At or above single-engine climb speed it can be done if you're sharp.
But don't bank on being sharp after a long flight involving an engine shutdown somewhere along the way.
So establish a single-engine I'll-land-come-hell-or-high-water attitude (agl) and minimum-airspeed
combination for your aircraft and stick to it. If you find yourself below that speed or altitude and a truck shows
up on the runway, pick a soft spot to hit on the airport. Because it's much better to wipe out the gear by landing
off the runway than to wipe out the whole airplane by spinning into the middle of it.
Summing it up-stay proficient (an annual check is a good idea), stay constantly aware of your airplane's
performance by analyzing the flight-manual information under realistic conditions, and have a plan of action
before things start to come unglued. The key philosophy of that plan of action is easy to remember and may
save your bottom — always leave yourself an out.
11
* Flying Light Twins Safely
The major difference between flying a twin engine and a single engine airplane is knowing how to manage the
flight if one engine loses power for any reason. Safe flight with one engine-out requires an understanding of
the basic aerodynamics involved as well as proficiency in engine-out procedures.
LOSS OF POWER ON ONE SIDE
Loss of power from one engine affects both climb performance and controllability of any light twin.
CLIMB PERFORMANCE
Climb performance depends on an excess of power over that required for level flight. Loss of power from one
engine obviously represents a 50% loss of power but, in virtually all light twins, climb performance is reduced
by at least 80%.
The amount of power required for level flight depends on how much drag must be "overcome" to sustain level
flight. It's obvious, that if drag is increased because the gear and flaps are down and the prop windmilling,
more power will be required. Not so obvious, however, is the fact that drag also increases as the square of the
airspeed while power required to maintain that speed increases as the cube of the airspeed.
Thus, climb performance depends on four factors:
* Airspeed - too little or too much will decrease climb performance.
* Drag - gear, flaps, cowl flaps, prop and speed.
* Power - amount available in excess of that needed for level flight.
* Weight - passengers, baggage and fuel load greatly affect climb performance.
YAW
Loss of power on one engine also creates yaw due to asymmetrical thrust. Yaw forces must be balanced with
the rudder.
Roll
Loss of power on one engine reduces prop wash over the wing. Yaw also affects the lift distribution over the
wing causing a roll toward the "dead" engine. (See figure 4) These roll forces may be balanced by banking into
the operating engine.
CRITICAL ENGINE
The critical engine is that engine whose failure would most adversely affect the performance or handling
qualities of the airplane. The critical engine on most U.S. light twins is the left engine as its failure requires the
most rudder force to overcome yaw. At cruise, the thrust line of each engine is through the propeller hub.
But, at low airspeeds and at high angles of attack, the effective thrust centerline shifts to the right on each
engine because the descending propeller blades produce more thrust than the ascending blades (P-factor).
Thus, the right engine produces the greatest mechanical yawing moment and requires the most rudder to
counterbalance the yaw.
KEY AIRSPEED FOR SINGLE ENGINE OPERATIONS
Airspeed is the key to safe single engine operations. For most light twins there is an:
* airspeed below which directional control cannot be maintained. Vmca
* airspeed below which an intentional engine cut should never be made. Vsse
* airspeed that will give the best single engine rate of climb (or the slowest loss of altitude). Vyse
* airspeed that will give the steepest angle of climb with one engine-out. Vxse
Minimum Control Speed Airborne (Vmca)
12
Vmca is designated by the red radial on the airspeed indicator and indicates the minimum control speed,
airborne at sea level. Vmca is determined by the manufacturer as the minimum airspeed at which it's possible
to recover directional control of the airplane within 20 degrees heading change and, thereafter, maintain
straight flight, with not more than 5 degrees of bank if one engine fails suddenly with:
* Takeoff power on both engines,
* Rearmost allowable center of gravity,
* Flaps in takeoff position,
* Landing gear retracted,
* Propeller windmilling in takeoff pitch configuration (or feathered if automatically featherable).
However, sudden engine failures rarely occur with all of the factors listed above and, therefore, the actual
Vmca under any particular situation may be a little slower than the red radial on the airspeed indicator.
However, most airplanes will not maintain level flight at speeds at or near Vmca. Consequently, it is not
advisable to fly at speeds approaching Vmca except in training situations or during flight tests.
Intentional One Engine Inoperative Speed (Vsse)
Vsse, is specified by the airplane manufacturer in new Handbooks and is the minimum speed at which to
perform intentional engine cuts. Use of Vsse is intended to reduce the accident potential from loss of control
after engine cuts at or near minimum control speed. Vsse demonstrations are necessary in training but should
only be made at a safe altitude above the terrain and with the power reduction on one engine made at or above
Vsse. Power on the operating (good) engine should then be set at the position for maximum continuous
operation. Airspeed is reduced slowly (one knot per second) until directional control can no longer be
maintained or the first indication of a stall obtained.
Recovery from flight below Vmca is made by reducing power to idle on the operating (good) engine,
decreasing the angle of attack by dropping the nose, accelerating through Vmca, and then returning power to
the operating engine and accelerating to Vyse, the blue radial speed.
Best Single Engine Rate of Climb speed (Vyse)
Vyse is designated by the blue radial on the airspeed indicator. Vyse delivers the greatest gain in altitude in the
shortest possible time, and is based on the following criteria:
* critical engine inoperative, and its propeller in the minimum drag position.
* operating engine set at not more than maximum continuous power.
* landing gear retracted.
* wing flaps in the most favorable (i.e., best lift/drag) ratio position.
* cowl flaps as required for engine cooling.
* airplane flown at recommended bank angle.
Drag caused by a windmilling propeller, extended landing gear, or flaps in the landing position will severely
degrade or destroy single engine climb performance. Single engine climb performance varies widely with type
of airplane, weight, temperature, altitude and airplane configuration. The climb gradient (altitude gain or loss
per mile) may be marginal or even negative - under some conditions. Study the Pilot's Operating Handbook for
your specific airplane and know what performance to expect with one engine out. Remember, the Federal
Aviation Regulations do not require any single engine climb performance for light twins that weigh 6000
pounds or less and that have a stall speed of 61 knots or less.
Best Single Engine Angle of Climb Airspeed (Vxse)
Vxse is used only to clear obstructions during initial climb out as it gives the greatest altitude gain per unit of
horizontal distance. It provides less engine cooling and requires more rudder control than Vxse.
SINGLE ENGINE SERVICE CEILING
13
The single engine service ceiling is the maximum altitude at which an airplane will climb, at a rate of at least
50 feet per minute in smooth air, with one engine feathered. New Handbooks show service ceiling as a
function of weight, pressure altitude and temperature while the old Flight Manuals frequently use density
altitude.
The single engine service ceiling chart should be used during flight planning to determine whether the
airplane, as loaded, can maintain the Minimum Enroute Altitude (MEA) if IFR, or terrain clearance if VFR,
following an engine failure.
BASIC SINGLE ENGINE PROCEDURES
Know and follow, to the letter, the single engine emergency procedures specified in your Pilot's Operating
Handbook for your specific make and model airplane. However, the basic fundamentals of all the procedures
are as follows:
* Maintain aircraft control and airspeed at all times. This is cardinal rule No. 1.
* Usually, apply maximum power to the operating engine. However, if the engine failure occurs during cruise
or in a steep turn, you may elect to use only enough power to maintain a safe speed and altitude. If the failure
occurs on final approach, use power only as necessary to complete the landing.
* Reduce drag to an absolute minimum.
* Secure the failed engine and related subsystems.
The first three steps should be done promptly and from memory. The check list should then be consulted to be
sure that the inoperative engine is secured properly and that the appropriate switches are placed in the correct
position. The airplane must be banked into the live engine with the "slip/skid" ball out of center toward the live
engine to achieve Handbook performance.
Another note of caution: Be sure to identify the dead engine, positively, before feathering it. Many red faced
pilots - both students and veterans alike have feathered the wrong engine. Don't let it happen to you.
Remember: First, identify the suspected engine (i.e., "Dead foot means dead engine"); second, verify with
cautious throttle movement; then feather. But be sure it is dead and not just sick.
ENGINE FAILURE ON TAKEOFF
If an engine fails before attaining liftoff speed, the only proper action is to discontinue the takeoff. If the
engine fails after liftoff with the landing gear still down, the takeoff should still be discontinued if touchdown
and rollout on the remaining runway is still possible.
If you do find yourself in a position of not being able to climb, it's much better to pull the power on the good
engine and land straight ahead than try to force a climb and lose control.
Pilot's Operating Handbooks have charts that are used in calculating the runway length required if the engine
fails before reaching liftoff speed and may have charts showing performance after liftoff such as:
* Accelerate-Stop Distance. That's the distance required to accelerate to liftoff speed and, assuming failure to
engine at the instant that liftoff speed is attained, to bring the airplane to a full stop.
* Accelerate-Go Distance. That's the distance required to accelerate to liftoff speed and, assuming failure of an
engine at the instant liftoff speed is attained, to continue the takeoff on the remaining engine to a height of 50
feet.
Study your accelerate-go charts carefully. No airplane is capable of climbing out on one engine under all
weight, pressure altitude and temperature conditions. Know, before you take the actual runway, whether you
can maintain control and climb out if you lose an engine while the gear is still down. It may be necessary to
off-load some weight, or wait for more favorable temperature or wind conditions.
WHEN TO FLY Vx, Vy, Vxse AND Vyse
14
During normal two engine operations, always fly Vy (or Vx if necessary for obstacle clearance) on initial
climb out. Then, accelerate to your cruise climb airspeed, which may be Vy plus 10 to 15 knots after you have
obtained a safe altitude. Use of cruise climb airspeed will give you better engine cooling, increased in-flight
visibility and better fuel economy. However, at the first indication of an engine failure during climbout, or
while on approach, establish Vyse or Vxse, whichever is appropriate. (Consult your Handbook or Flight
Manual for specifics).
SUMMARY
Know the key airspeeds for your airplane and when to use them:
Vmc (Red Radial) -- never fly at or near this airspeed except in training or during flight test situations.
Vsse never intentionally cut an engine below this airspeed.
Vyse (Blue Radial) -- always fly this airspeed during a single engine emergency during climbout (except when
necessary to clear an obstacle after takeoff) and on final approach until committed for landing.
Vxse - Fly Vxse to clear obstacles, then accelerate to Vyse.
Know the performance limitations of your airplane, including its:
* accelerate-stop distances,
* accelerate-go distances,
* single engine service ceiling, and
* maximum weight for which single engine climb is possible.
Know the basic single engine emergency procedures:
* Maintain control of the airplane by flying at the proper airspeed.
* Apply maximum power, if appropriate.
* Reduce drag (includes feathering).
* Complete engine-out checklist.
And finally, put your knowledge into practice with a qualified instructor pilot observing and assisting you.
Engine failures can be handled competently and safely by proficient pilots. Keep your proficiency up and
every flight in a multiengine airplane should be a safe one.
15
* Transitioning to Twins
One of the most interesting challenges in aviation for any pilot is transitioning to a new type aircraft.
Normally, the pilot's first question is, "How do I start?"
That question is an easy one to answer. The best way to transition to any new aircraft is to find a certificated
flight instructor (CFI) qualified and current in the aircraft to teach you how to fly it safely. If the transition is to
a high performance aircraft or one that requires a category or class rating or one that requires a type rating such
as a turbojet, you might want to attend one of the many flight training schools that specialize in such training.
Another option is to attend the aircraft manufacturer's training course for the model if the company offers such
a course. Regardless of where you attend training, the best way to transition to a new aircraft is to work with
someone, preferably a CFI, who is current in the new aircraft. In some cases, you may need the appropriate
CFI endorsement to fly the aircraft such as a high altitude, tail wheel, or high performance endorsement. If you
cannot find a CFI to fly with, the next step is try and find another experienced pilot who is current in the
aircraft. This is especially true if the aircraft is an experimental aircraft or a very rare model. The reason is
every aircraft is unique. By flying with someone current in the make and model of aircraft, the transition-ing
pilot gets the benefit of the other pilot's experience and knowledge plus the added safety of someone who
knows the air-craft. What a transitioning pilot does not want to do is become a test pilot in a new aircraft.
HITTING THE BOOKS
With the question of how should I begin answered, the next question is where do I begin. You begin by
studying and learning the new aircraft's systems and operating procedures since the bottom line to all flying is
knowing everything that we can about the aircraft so we can operate it safely. You will find this information in
the aircraft's flight manual (AFM), owner's manual, or pilot's operating handbook (POH). If the aircraft is an
older model, it might have a very basic owner's manual. If so, you need to be aware that the older manuals may
not have the same information as some of the newer manuals, nor are the older manuals organized like the
newer POH's or AFM's. Although the older manuals have less information than the new manuals, they still 5
provide the basic information.
The newer publications are similar in format and have the following sections: General; Limitations;
Emergency Procedures; Normal Procedures; Performance; Weight and Balance/Equipment List; Systems
Description; Handling, Service, and Maintenance; Supplements; and Safety Information. Another good source
of information on an aircraft, particularly older models, is magazine articles on the aircraft. Pilot reports are
especially helpful.
COCKPIT FAMILIARIZATION
Once you have done your homework and thoroughly understand the new aircraft, you should take the aircraft's
manual and checklist out to the aircraft and spend time sitting in the cock-pit to learn the locations of the
various controls, instruments, and checklist procedures. Your goal is be become familiar enough with the
aircraft to be able to fly it before you ever start the engine. If you are renting the aircraft, this procedure also
will save you valu-able training dollars. You don't have to pay a CFI to teach you something that you can
review on your own. When you are comfortable with the location of every item in the cockpit and with the
aircraft's procedures and numbers, it is time to go flying with a CFI or pilot current in the aircraft.
CHECKOUT GUIDE
The following is a list of areas you should consider when transitioning to any type of aircraft:
1. Aircraft Systems.
2. Limitations which include performance, weight and balance, and V speeds.
3. Normal Procedures.
4. Abnormal and emergency procedures.
5. Aircraft paperwork and records.
16
6. Checkout by a current and qualified CFI or experienced pilot that knows the aircraft's particular flight
characteristics. The checkout pilot should be current in make and model.
AIRCRAFT KNOWLEDGE
After reviewing the General section of the AFM or POH the Aircraft Systems portion is probably the best area
to start serious study. If you start in another section, you may encounter terms you aren't familiar with if you
haven't studied the various systems first. This is particularly true of the more complex and turbine powered
aircraft.
Aircraft systems not only include the engine, fuel, electrical, landing gear, control, and hydraulic systems but
the avionics systems as well. With today's rapid changes in avionics systems, a pilot must be very familiar with
the newer equipment and how it is operated. This is especially important when flying in different air-craft that
have different avionics packages. Pilots need to be aware that the new GPS and older LORAN-C receivers can
have different control functions, programming, data displays, and operating procedures. Because each GPS or
LORAN-C system is unique, the time to lean how to operate the system is when you are on the ground; not
when you are in flight.
TYPES OF EQUIPMENT QUESTIONS TO ASK
The engine is a good place for transitioning pilots to start their study.
 Is it a turbine or recip?
 If it is a reciprocating engine, is it carburetor equipped, fuel injected, or turbocharged?
 What type fuel does it use?
 How much fuel does it carry?
 What is its usable fuel capacity?
 What is the average fuel burn rate in normal cruise?
 What type of fuel system does it have?
 Is it single tank or multiple tanks?
 Is fuel drawn from one tank at a time or is fuel drawn from all or multiple tanks simultaneously?
 Does the fuel gauge automatically indicate the fuel in the tank you have selected or is there a separate
switch you must activate to get the fuel gauge to indicate the fuel quantity in the tank you have
selected?
Some aircraft have a separate switch for the fuel gauge. You can be looking at a fuel gauge that indicates
plenty of fuel when the engine quits because you just drained a tank that the fuel quantity indicator was not set
to. If this happens at low altitude, it could lead to a disaster.
Even when the fuel quantity indicator indicates the tank selected or when there are multiple fuel quantity
indicators there have been accidents due to fuel starvation because one tank was drained and the fuel selector
had not been switched to the tank that had plenty of fuel in it. How does the crossfeed work? In multi-engine
aircraft the crossfeed may work differently in different aircraft. These are only a few of the types of questions
a pilot 7 needs to answer when transitioning to a new aircraft.
HABITS CAN BE DANGEROUS
Although knowledge of the new aircraft's operating systems is important, pilots must also be aware that old
operating habits can be deadly when transitioning between aircraft. For example, since we just discussed how
different aircraft can have different fuel operating systems, let's suppose you lose an engine in a twin you are
transitioning to on a dark and stormy night.
Now let's suppose in the stress of the moment, you revert to an old habit. You use the crossfeed procedures for
a twin you normally fly instead of the different procedure for the new aircraft. You might just have shut off the
fuel to your only remaining operating engine. Another example of how a habit can cause you a problem in a
new aircraft is using the wrong technique to lean the engine. There is at least one make and model of aircraft
17
that will use substantially more fuel than the performance charts indicate if you use the traditional leaning
technique from habit. We have been taught to lean until we get peak RPM (in aircraft with fixed-pitch
propellers), then enrich the mixture until there is a 25-50 RPM drop.
However, in at least one aircraft the leaning instructions are to lean until the RPM is at peak, then continue to
lean until there is a 25-50 RPM drop. There is a warning that fuel consumption can be 10 percent higher if the
first method is used instead of the recommended procedure. There is also a warning that not following this
recommended procedure and leaving the mixture in the full rich position can increase fuel consumption as
much as 40 percent and decrease flight endurance by as much as 70 minutes from what is published in the 75
percent power performance figures.
Since old operating habits can be deadly to pilots transitioning between aircraft with different operating
procedures, pilots need to be aware that during stressful or emergency situations in the new aircraft, they may
use the wrong procedures. In such situations, pilots must make sure they are using the correct procedure for the
aircraft they are flying. Pilots must be particularly careful anytime they are making any changes involving the
fuel system or the landing gear system.
SYSTEMS OVERLAP
Aircraft operating systems can also overlap and cause problems. This is particularly true of the electrical and
hydraulic systems involving the landing gear and control systems. This relationship is extremely important. In
one incident, a pilot had a total electrical failure in an aircraft that had an electrically operated landing gear
system. After the gear up landing, the pilot said he knew the gear down indicators would not work because
they were electrically operated. He thought the gear was down because the manual indicator showed they were
down after he had put the gear handle in the down position. When asked if he had lowered the gear manually,
he said, "No."
If this pilot had possessed more insight into the interrelationship between systems this incident might not have
occurred. We mentioned avionics systems. Fatal accidents have occurred because pilots set up their
navigation/communication systems improperly. No more needs to be said.
LIMITATIONS, PERFORMANCE, AND WEIGHT AND BALANCE
These three areas are very closely interrelated. Operating at airspeeds where you get the best performance
could be a limitation, since increasing or decreasing speed would decrease desired aircraft performance. An
example of this is L/D max. This is where the lift to drag ratio is the greatest or the airspeed where you get the
most lift for the least drag. Why is this important?
This is the speed which would give the aircraft the greatest gliding distance in the event of a complete power
failure. You would need this performance to reach a safe landing area. Changing speed would only reduce
your chances of making the field. Weight and performance are closely interrelated. Increasing weight reduces
performance. This will cause an increased takeoff distance, reduce an aircraft's rate-of-climb capability, and
cause the true airspeed to be less at a given power setting and density altitude.
Although pilots should always compute the weight and balance and performance data for every flight, this
information is especially important when transitioning to a new aircraft. Aircraft speeds, the various "V
Speeds," are also important for the safe operation of any aircraft. It is recommended pilots know the following
V Speeds that apply to their particular aircraft:
 Vso Stalling speed or the minimum steady flight speed in the landing configuration
 Vs1 Stalling speed or the minimum steady flight speed in a specified configuration
 Vr Rotation speed
 Vmc Minimum control speed with the critical engine inoperative (multiengine aircraft)
 Vso Recommended final approach speed in the landing configuration (if none specified in the aircraft's
documentation)
18










Vx Speed for the best angle of climb
Vxse Speed for the best angle of climb (one engine inop in multiengine aircraft)
Vy Speed for the best rate of climb
Vyse Speed for the best rate of climb (one engine inop in multi-engine aircraft)
Vlo Maximum landing gear operating speed
Vle Maximum landing gear extended speed
Vfe Maximum flap extended speed
Va Design maneuvering speed
Vne Never exceed speed
L/Dmax Airspeed that gives you the maximum gliding distance over the ground with complete power
failure
Obviously these are a lot of numbers to memorize, however it must be remembered what was said at the
beginning of this article, a pilot must know how to operate his or her aircraft safely.
Knowing V Speeds is part of knowing what to do not only when something goes wrong but also when things
are going right. One way to remember these speeds is to write them on 3 x 5 inch cards and have them where
they can easily be referred to just prior to specific flight operations. Many of these speeds are also marked on
the instrument panel, some operating controls, and the airspeed indicator.
There are many other limitations that a pilot needs to know such as manifold pressure, RPM, engine oil
temperature and pressure, cylinder head temperature, hydraulic pressure limits, volt and loadmeter readings,
etc. Fortunately for most of us, the air-craft we fly normally have these marked with color-coded indicators.
However, it is important to know where the needles normally point so that any change will be noticed.
NORMAL, ABNORMAL, AND EMERGENCY PROCEDURES
One of the best and safest ways to become familiar with these procedures is in a flight simulator designed for
your particular make and model of aircraft. Since the majority of the smaller general aviation aircraft do not
have simulators, there is another way to become proficient in such aircraft at no cost when the actual aircraft is
available and not in use.
This is to just get into the air-craft with the owners manual and begin to familiarize yourself with the cockpit.
This includes going over the checklists to familiarize yourself with the location of the knobs, switches, and
handles in the cockpit, and the pattern that develops when running the checklist.
Some flight training institutions require their students to pass what is known as a blindfold cockpit check
which is literally just that. You have to memorize the location of each item in the cockpit then put on a
blindfold and be able to touch each item called out by the check pilot without being able to look for it. If this
seems a little extreme, think how invaluable this ability would be during a high workload situation under
single-pilot operations.
Envision yourself alone in the cockpit on a dark and stormy night on an instrument approach when the landing
gear indicator does not indicate a normal down and locked position. It sure would be nice to know exactly
where the landing gear motor and landing gear circuit breakers are so you could reach over and feel to see if
they are popped instead of having to look for them which could break down your scan, or worse, possibly
induce vertigo.
When using a static aircraft as a training device, you should run through all the checklists as many times as
necessary to become thoroughly familiar with their content and the location of all of the controls and items
contained in the list or lists. Do each item that can be safely done on a static aircraft. However, DO NOT
MOVE THE LANDING GEAR HANDLE AT ANY TIME DURING THIS TRAINING ACTIVITY.
19
Also, be aware that there may be other persons around the aircraft when you are operating such items as flaps
and spoilers so you must use extreme caution when activating such devices. When applying power to any aircraft or starting any aircraft, you must always ensure the safety of others in the immediate area. You must
never apply power when others are working on an aircraft without coordinating your actions with those
working on the aircraft.
The reverse is also true. When you are working on an aircraft, you should either lockout or mark those controls
or switches that would endanger you if some-one inadvertently activated them while you are working on the
air-craft. This is particularly true when you are working on large air-craft where you may be out sight of
someone in the cockpit.
CHECKLISTS
We have used the word "memorized" in this article several times; however, when it comes to checklists, they
are not to be 11 memorized. A checklist is for checking that an item isn't forgotten. This brings up the rather
controversial subject of how to use a checklist. This subject is especially controversial if a multi-pilot crew is
involved and the pilots have different ways of doing a procedure. This potential conflict is why the aviation
industry and FAA have spent so much time and money on teaching crews how to work together.
Whether you are a single pilot or part of a multicrew cockpit, the important thing to remember is to use a
checklist in a way that insures you don't inadvertently skip an item. We said checklists are not to be
memorized. This is true for normal procedures. It is not necessarily true for all aircraft when it comes to
emergency procedures. In many aircraft flight manuals, in the emergency procedures section, there are
immediate action items that must be done if certain emergencies occur. These immediate action items
obviously must be memorized and then followed up later with the checklist when circumstances permit.
Some checklists are nice to memorize. Using the example of a night instrument approach when the gear
doesn't indicate down and you need to lower it manually, it would be nice to know what the proper procedure
is before you have to do it for real without ever having read the manual. This is why it is important for all
pilots to periodically review their aircraft's operating and emergency procedures. Better yet, hire a CFI for
some recurrent training. Remember to always use your checklist.
THE AIRCRAFT, AIRCRAFT PAPERWORK, AND RECORDS
Before you can have a safe flight you must have a safe pilot, a safe aircraft, and safe weather. To have a safe
aircraft you must have an airworthy aircraft. An aircraft is considered airworthy when it conforms to its FAAapproved type certificate data and is in condition for safe operation. Conformity to the type certificate is
considered attained, when the required and proper components are installed and they are consistent with the
drawings, specifications, and other data that are part of the type certificate.
Conformity would include applicable supplemental type certificates (STC's) and field-approved alterations,
and airworthiness directives. "In condition for safe operation" refers to the condition of the aircraft with
relation to wear and deterioration. If one or both of these conditions are not met, the aircraft is unairworthy.
So, who's responsible for ensuring an aircraft is airworthy and what do they check? The pilot in command
(PIC) is responsible for ensuring the aircraft is safe before each flight. The aircraft owner or operator is
primarily responsible for maintaining the aircraft in an airworthy condition. Both share responsibility for
ensuring the aircraft is safe for flight. The following are some of the items a pilot should check before each
flight.
FAR PART 91 PREFLIGHT CHECKS
1. Annual inspection-within 12 calendar months and signed off by an FAA-certificated airframe and power
plant mechanic with inspection authorization (IA).
2. 100 hour inspection-if required for the type of operation planned.
20
3. Airworthiness Directives (AD's)-all complied with (both one-time and recurrent).
4. Altimeter system and altitude reporting equipment tests and inspection-within 24 calendar months for IFR
operations in con-trolled airspace.
5. Transponder test and inspection-within 24 calendar months.
6. ELT inspection-within 12 calendar months. Battery-not expired.
7. VOR operational check-within the last 30 days and the results logged (if used for IFR operations)
DOCUMENTATION-"ARROW"
1. Airworthiness Certificate
2. Registration Certificate
3. Radio station transmitter license issued by the FCC if a transmitter is installed
4. Operating limitations found in the Airplane Flight Manual or Owners Handbook with appropriate placards
and markings
5. W eight and Balance Documentation
This list may not be all inclusive. The PIC is responsible for ensuring the flight complies with all of the
appropriate FAR. The Airworthiness Certificate states in part "...this airworthiness certificate is effective as
long as the maintenance, preventative maintenance and alterations are performed in accordance with Parts 21,
43, and 91 of the Federal Aviation Regulations, as appropriate, and the aircraft is registered in the United
States."
This statement means not only the above checklist items but all applicable regulations are required to be
complied with for the airworthiness certificate to be effective. To determine the aircraft is "in condition for
safe operation" requires a good preflight by the pilot in accordance with the aircraft manufacturer's
recommendations to determine "wear and deterioration" have not created any unsafe conditions.
AIRCRAFT CHECKOUT
What constitutes a good aircraft checkout?
It depends on the complexity of the aircraft and the ability of the pilot being checked out as well as the ability
of the pilot doing the checkout. What would be adequate in a single-engine, fixed-gear aircraft obviously
would not be adequate for a complex single or twin and what is adequate in a recip twin would not be adequate
in a turbine powered aircraft.
For small recip singles and light twins the following is one suggested checkout. Review the previous items
discussed in this article-systems, limitations, procedures, cockpit arrangement, various load configurations,
etc. Then review the standard flight training procedures that you will use to familiarize yourself with the
aircraft's flight characteristics.
One good guide is the FAA Practical Test Standards (PTS) appropriate to your rating. For example, if you are
a commercial pilot, you would use the commercial PTS while conducting your checkout. At a minimum, the
Private Pilot PTS is a good lesson and flight outline for a detailed aircraft checkout. The following outline will
help you become familiar with a new airplane.
1. A detailed preflight using a checklist.
2. Start, taxi and run-up.
3. Takeoff series and aborted takeoff practice.
4. Turns, climbs, and descents.
5. Flight at minimum controllable airspeed.
6. Stall series (appropriate to the aircraft). Remember to use clear ing turns.
7. Steep turns.
8. Simulated emergencies (appropriate to the aircraft).
9. Landing series and go-around.
10. Shutdown and post flight.
21
11. Fueling procedures.
12. Discrepancy reporting procedures.
13. Appropriate aircraft endorsement if required such as a high performance or tail wheel aircraft
endorsement-if needed (must be from an authorized flight instructor).
PILOT REQUIREMENTS
The above information has dealt mainly with the aircraft's requirements. We also need to mention the pilot's
requirements. Pilots need to comply with the following requirements:
1. Pilot certificate-with appropriate ratings and in your personal possession.
2. Medical-current and appropriate for the type of flight to be conducted and in your personal possession (if
required for the operation).
3 Flight review or its equivalent with appropriate logbook endorsement.
4. Meet the recent flight experience to be pilot in command (PIC) if carrying passengers. PIC's must meet the
appropriate requirements of FAR ß 61.57 which include:
a. A takeoff and landing requirement for any passenger carrying flight such as the requirement for:
(1) Any aircraft: Three takeoffs and landings as the sole manipulator of the flight controls in an aircraft of the
same category and class and, if a type rating is required, of the same type, within the preceding 90 days.
(2) Tailwheel aircraft-The required landings must be to a full stop.
(3) Night currency for night flights. The required three takeoffs and three landings must be made to a full stop
in the same category and class aircraft to be used. These must be done during that period beginning one hour
after sunset and ending one hour before sunrise (as published in the American Air Almanac).
b. Instrument currency for any IFR operation as PIC. Unless the pilot has logged at least six hours of
instrument time under actual or simulated IFR conditions, at least three of which were in flight in the category
of aircraft involved, including at least six instrument approaches within the past six months, or passed an
instrument competency check in the category of aircraft involved within the past six months. Glider pilots
must have logged at least three hours of instrument time with at least half of that time in a glider or aircraft. If
passengers are to be carried in a glider, the pilot must have logged at least three hours of instrument flight time
in gliders.
This article is about how to transition to another aircraft, but the important thing to keep in mind is not just
how we do something in aviation, but how well we do it. Have a safe flight.
Additional Reading: Advisory Circular (AC) 20-5F, Plane Sense AC 61-9B, Transition Courses for Complex
Single Engine and Light, Twin-Engine Airplanes AC 60-22, Aeronautical Decision Making AC 61-84B, Role
of Preflight Preparation
22
* Flight At Minimum Controllable Airspeed
Every properly executed takeoff and landing you make requires you to operate the airplane at low airspeed.
During training, students are taught "flight at minimum controllable airspeed" so they may learn the effect that
airspeed has on airplane performance and controllability. Information evaluated by the Data Analysis Section
of the Federal Aviation Administration reveals that about 65% of the reportable airplane accidents occur
during the takeoff and landing phases of flight. This indicates flight at low airspeed has a high accident
potential. Pilots who are skillful and confident in operating an airplane at low speeds may prevent many of
these accidents. In getting acquainted with a new or different airplane, experienced pilots can and do use
"flight at minimum controllable airspeed." Listed below are some of the objectives for teaching flight at
minimum controllable airspeed:
1. The student will be able to recognize that the airplane is approaching or has attained a critically low
airspeed.
2. The student will be able to control the airplane at airspeeds just above the stall.
3. To increase the confidence of the pilot in his ability to operate the airplane throughout its full range of
controllability.
There is more training value to the maneuver than just showing how slow the airplane can be flown. For
example, the following items should be demonstrated and taught:
1. Airplane attitude at minimum controllable airspeed.
2. Power required versus airspeed produced.
3. Trim needed.
4. Control effectiveness.
5. Turns and rate of turn compared to degree of bank.
6. Stall as a result of level turn.
7. Adverse yaw.
8. Effect of flap extension.
9. Effect of flap retraction.
10. Descents and descending turns.
11. Climbs and climbing turns.
12. Attempted operation "behind the power curve.
13. Go-around procedures.
The instructor needs to describe "Minimum Controllable Airspeed." This is not a set figure. It will vary with
loading, configuration, power setting, and pilot technique. It is best described as a speed just above stall or a
point at which a further reduction in airspeed, or an increase in angle of attack or load factor will cause an
immediate physical indication of a stall. The physical indication would be shuddering, pitch down of the nose,
rolling to right or left, or reaching the limit of up elevator travel. The goal for proficiency will be to have the
student hold within 100 feet of prescribed altitude and airspeed within the range between minimum
controllable airspeed and that speed +5 knots.
The instructor should provide a basis for comparison of control pressures and rates of response. While in
cruise flight at cruising airspeed, have the student use rudder, aileron and elevator and note the pressure
applied and the response rate.
Then, while maintaining heading and altitude, reduce power and increase angle of attack, slowing the airplane
to minimum controllable airspeed. As speed is reduced, point out a change in pitch. A change in pitch attitude
is needed in order to maintain altitude. There will be a point at which pitch change alone does not increase lift
to the point that altitude can be maintained. Power must be added, and point out, he is now operating "behind
the power curve." The angle of attack must be decreased before altitude can be gained, even when maximum
power has been applied.
23
Another way of saying it is, he must add power to go slower while maintaining altitude.
When all set at minimum controllable airspeed, demonstrate how to recognize that the airplane is close to
operating limits: sight, sound, and feel give the clues. The pitch attitude of the nose, the angle of the wing tips
in reference to the horizon, the sound of the engine compared to the lack of wind noise, the lessened resistance
to control pressures and the need of elevator and rudder trim all tell that the airplane is at a low airspeed. now
have the student apply aileron, elevator, and rudder pressures and note the response. Everything still affects the
airplane the same way except that greater control movement is needed to produce the same rates of response
that were obtained at cruise speed.
Now roll smoothly into a medium banked turn. This is done to show the student the airplane is maneuverable
even at low airspeed. The medium bank results in a high rate of turn at this low airspeed. It will seem that the
airplane is almost pivoting over a point on the ground. Point out that a steep bank is not needed in order to
obtain a high rate of turn when operating at low airspeed.
The turn made at medium bank is also used to demonstrate that a level turn does increase stall speed and,
unless power is added, a stall will occur soon after the turn is established. when the first indication of stall is
felt, point out the stall indication to the student and gently recover by simultaneously reducing the angle of
attack, adding power, and rolling out of the turn. (if the instructor doesn't appear nervous or apprehensive
about the stall and recovery, the student will be favorably impresses and his confidence will be increased.)
Return to straight and level flight and set up at minimum controllable airspeed, demonstrate the reason for
proper coordination of rudder and aileron in turn entry and recovery. In other words, demonstrate adverse yaw.
While the student watches the nose of the airplane to compare its movement against outside references, use
aileron only to establish a banked attitude. He will note that application of left aileron causes the nose to show
yaw. As left aileron is used, the right wing tip would appear to move aft. The amount of yaw obtained will be
affected by the degree of aileron applied and the design of the system. Some ailerons are rigged for differential
travel to minimize adverse yaw. In this case the yaw is most easily seen by sighting across the wing tip.
Now, demonstrate properly coordinated turn entries and recoveries so the student can see and feel the
difference.
Next on the list is the demonstration of the effect of flaps on minimum controllable airspeed and airplane
attitude. Extending full flaps will cause the airplane to "balloon" (to climb above desired altitude). Ballooning
is caused by the combination of airspeed and the increase in coefficient of lift which occurs when the flaps are
extended. Drag also results from the flap extension. As the airplane decelerates, lift is reduced. When all forces
(lift, thrust, weight, and drag) are again stabilized, the airplane will have a new, lower minimum controllable
airspeed and a different pitch attitude for level flight. The power setting may be the same as before the flaps
were added, or if a power change is needed to maintain level flight, it will be a small one.
When the airplane is established in straight and level flight with the flaps down, turns can be demonstrated,
again noting response rates to control pressures and high rate of turn produced by medium banked turns.
Descents can be performed by reducing power while maintaining airspeed. While descending, turns to the
right and left should be practiced. Now, power can be applied to climb. At this time, if the airspeed has been
allowed to get excessively low, it may be impossible to climb even with full power. By reducing the amount of
flap extension, we can also reduce drag and should now be able to climb.
If the flaps are manually actuated, rapid retraction can result in a stall. This point should be demonstrated. If
the flaps are electrically or hydraulically actuated, retraction may be slow enough that the airplane will
accelerate so that flaps-up stall speed is attained before the flaps are fully retracted. In the case of manual flap
operation, slower, smooth retraction will also permit acceleration as drag is reduced and a stall will be avoided.
24
All that is needed is a pitch change in order to maintain level flight or prevent sinking as the flaps come up. In
other words, the pitch change compensates for the change of camber and coefficient of lift of the wing.
Climbs and descents, in straight flight and turns, with and without flaps should be practiced.
To complete the demonstration, attempt a simulated go-around with flaps fully extended. As in attempting a
climb, conditions of power, load, and configuration may make acceleration and climb impossible. It is
suggested that the go-around procedure be:
1. Power - smoothly increase to full or climb power, as appropriate.
2. Flaps up - (to 1/2 position, complete retraction after flaps up stall speed is reached.)
3. Carburetor heat "OFF" if used.
4. Gear up when climb is established and touchdown is unlikely.
If the Owner's Manual suggests a specific procedure, we suggest following that recommendation.
Climb to and level off at the altitude specified by the instructor should follow the go-around.
If the Owner's Manual suggest a specific procedure, we suggest following that recommendation.
Climb to and level off at the altitude specified by the instructor should follow the go-around.
This suggested procedure for demonstrating and practicing "Flight at Minimum Controllable Airspeed" does
take a few minutes to go through. Keep alert for indications of engine overheating as indicated by cylinder
head or oil temperatures. If the airplane is equipped with cowl flaps, teach the student how to use them to keep
temperatures within limits. I no cowl flaps are e installed, it may be necessary to increase speed for cooling.
All throughout the demonstrations, point out the relationship between pitch attitude, power setting, and the
results obtained. The results would be climb, descent, or level flight. Performance is a function of angle of
attack. Angle of attack is controlled through the combined use of pitch attitude and power setting.
25
* Engine-Out Booby Traps for Light Twin Pilots
By Melville R. Byington, Jr.
Professor of Aeronautical Science, Embry-Riddle Aeronautical University (From the AOPA Air Safety
Foundation, April 1993.)
BACKGROUND
Previous research into the engine out flying characteristics of light twins has identified the critical effect of
pilot technique, particularly with respect to the proper bank angle. The "Five Degree Forever Syndrome",
defined in Reference 1, continues to die slowly. Most multiengine pilots have accepted the reality that, for
engine-out operations, the once popular "five degree bank angle into the operating engine" PROVIDES
NEITHER BEST CLIMB PERFORMANCE NOR BEST DIRECTIONAL CONTROL.
Best performance demands minimum drag, corresponding to zero sideslip flight, which corresponds to bank
angles much less than five degrees. "Best" directional control, presumably meaning least rudder pressure,
requires bank angles greater than five degrees, by which climb performance suffers severely. The "magic" five
degree value simply is a holdover from FAR 23.149, which permits the manufacturer's test pilots a bank angle
of up to five degrees for the purpose of determining the nominal Vmc. The manufacturer desires a low
nominal Vmc and employs the full 5 degree bank for this test.
The manufacturer also conducts engine out rate of climb tests under conditions designed to cast the results in
the most favorable competitive light. New airplanes and engines are flown by factory test pilots under
optimum conditions, INCLUDING ZERO SIDESLIP. MINIMUM DRAG CONDITIONS OF FLIGHT,
These measured data form the basis for engine-out climb performance estimates found in the pilot operating
handbook (POH).
THE PROBLEM
Typical pilots fly airplanes several years and thousands of hours old. The airframes and engines no longer are
new, but the POH data is of original vintage. Moreover, the POH recommended engine-out climb bank angle
is likely to guarantee performance inferior to the optimum available. Even though precluded by physical law,
the POH may predict a positive climb rate for prevailing weight and ambient conditions. The conscientious
pilot who obtains and naively accepts this positive POH climb estimate is in an unenviable predicament. Under
such circumstances, attempts to achieve a positive climb rate are futile. Worse yet, unless correctly recognized
and managed, loss of flying speed and a fatal stall/spin crash may follow.
Figure 1 depicts typical light twin engine-out characteristics under nominal conditions of equipment age and
condition, weight, and density altitude (DA). See Reference 1 for details of three models. The strong influence
of bank angle is evident in this "rooftop" curve, with peak performance corresponding to zero sideslip (ZS)
flight at point B. Both zero bank (A) or five degree bank (C) degrade climb performance from the optimum
(ZS) condition. Bank angles beyond 5 degrees (D) may preclude climbing even under "nominal" conditions.
Tests of four light twin models, two for "critical" and two for non-critical engine flight, showed that the
average optimum bank angle at point B corresponded to 2.1 degrees. The average slope of the curve between
B and D was thirty feet per minute loss per degree of "overbank."
Figure 1 (point E) also depicts the typical POH climb prediction and recommended bank angle for engine-out
climb. The POH predicted climb performance (E) is unachievable at five degrees bank and usually even under
the most favorable conditions (B, at zero sideslip). In addition to the unwelcome drag addition from excessive
bank angle, Reference 2 warns against the threat of unporting the fuel tank feeding the operable engine.
Rate of climb (ROC) measurements were conducted for four models and seven engine-airframe combinations.
Table 1 summarizes results. Actual climb rates were compared to POH predicted rates for existing weight and
DA, both under optimum (zero sideslip) and under POH recommended conditions (usually at the 5 degree
26
bank angle). Differences between POH ROC estimates and measured performance are tabulated. Comparisons
between the POH estimates and optimum conditions correspond to Figure 1, point E minus point B ROC
values. Likewise, comparisons to ROC when flown as recommended corresponds to points E minus C. For
example, consider case #4. The best available RCC at ZS was 138 FPM inferior to corresponding POH
forecasts. When flown as recommended at 5 degrees bank, RCC deteriorated an additional 85 FPM and
became 223 FPM inferior to POH predictions.
In no test was POH performance achieved when flown as recommended by the POH. In one case (#I),
involving relatively new equipment, the POH figure was exceeded marginally when zero sideslip was used.
The identical airplane was retested as shown in cases 2 and 3. The original performance was not reproducible,
and the decrements appear related to airframe and engine time.
While Figure 1 depicts "nominal" conditions of equipment, weight, and (DA), it is instructive to consider
conditions more and less favorable than nominal. Figure 2 shows more favorable conditions resulting from
some combination of lower weight, lower DA, or better equipment condition. This causes the curve to move
vertically upward across the full scale. Climb performance is improved at all bank angles, and this may mask
sloppy airmanship. Despite greater margins of error, compared to Figure 1, it is important to note no
significant change occurs to:
1. optimum bank angle (still approximately 2 degrees).
2. slope of the curve (approximately 30 FPM per degree).
3. difference between POH forecast (point E) and achievable ROC, for any bank angle.
Similarly, Figure 3 depicts less favorable conditions resulting from some combination of higher weight, higher
DA, or poorer equipment condition. In this challenging situation, positive climb is possible only near zero
sideslip conditions despite POH indications to the contrary. Only precise airmanship permit a positive climb
rate.
Table I (Measured vs POH Rate of Climb)
# MODEL
A/F hrs
ENG hrs
Optimum ROC
(E-B)
(E-C)
Per ROC
RMKS
1 Cessna 303
2130
199(L/R)
+13
-78
2 Cessna 303
6400
1004(L)
-77
-168
3 Cessna 303
6400
1005(R)
-47
-138
4 Beech A65
16937
1684(R)
-138
-223
5 Beech A65
11534
162(R)
-28
-83
6 Beech 58
3769
1450(R)
-150
-150
Note 1
7 Piper PA 44
Unknown
Unk(L/R)
-88
-142
Note 2
-74
-140
AVERAGE
Note 1: No bank angle specified in POH. Best case assumed.
Note 2:'Tbree to five degrees" recommended 4 degrees assumed.
LOSS OF CONTROL HAZARDS
Reference 1 reported an analysis of light twin accidents following engine failure in the initial climb after
takeoff. It showed that 57% of these accidents and 75% of fatal/serious injuries resulted from situations in
which control was lost. Low airspeed results from vain attempts to climb or hold altitude under conditions
27
which render this impossible. Loss of control typically results from low airspeed combined with too much or
too little bank angle, i.e., either more or less than that corresponding to zero sideslip.
Analysis was conducted of light twin engine-out stall/spin accidents in the initial climb out after takeoff. A 28month period (1 /84 through 5/86) was studied. Analysis revealed:
1. at least 7.7 accidents and 24 fatalities per year on average, and
2. a 95% fatality rate for occupants in such crashes.
Reference 2 reports data covering engine-out fatal stall /spin accidents over a six year span (1983-89). Fatal
stall/spin accidents comprised 10% of all multiengine fatal accidents. Half of these accidents occurred during
training situations.
Causes of the frequent and lethal engine-out stall /spin accidents apparently deserve better understanding by
light twin pilots. Low airspeed, combined with bank angles greater than those for zero sideslip (approximately
two degrees), "sets the trap" for the unwary. 71w reason is illustrated by smoke tunnel photographs in Figure
4. Flow conditions are depicted by the smoke wisps and the yaw strings on the nose.
Figure 4a depicts the airplane in zero slip flight with well behaved airflow over both wings. Figure 4b depicts
the airplane in a (right) bank greater than optimum for climb with the left engine failed and propeller
feathered. This case requires somewhat less rudder deflection. The airflow on the lowered (right) inner wing is
no problem, since it is not blanked by the fuselage and benefits from the propeller's high energy, slipstreaminduced airflow. Conversely, the raised (left) inner wing suffers from disturbed, low energy airflow. This
arises from the combination of the nacelle and propeller disturbance plus the fuselage's blanking effect.
Consequently, the raised wing will stall at a substantially higher airspeed than would occur in zero sideslip
flight.
The fuselage's blanking effect also will distort airspeed indicator accuracy, giving a false high or low reading.
The amount and type of error depends on system characteristics and which engine is operating.
Reference 2 reports engine-out stall speeds 9-20 knots IAS greater than power-on stall speed for the Baron
B55. During the author's flight tests of the Queenair A65, engine-out stall buffet was encountered 25 knots
above the published Vs under severe sideslip conditions at 9.5 degrees bank.
With five degrees or greater bank, the pilot must hold a large amount of (right) wheel to maintain lateral
control. Aileron deflections add to drag and further increase the left wing's angle of attack, while reducing that
of the right wing. The trap is ready to snap!
Reference 2 asserts that "a single-engine stall in most (multi-engine) airplanes will result in loss of control."
Indicated airspeed may read well above Vs when the trap snaps shut. The airplane begins a sudden,
uncommanded left roll. The roll motion, coupled with any remaining "corrective" aileron deflection, further
increases the left wing's angle of attack, deepens the stall, and produces a spin. Readers can probably recall
headlines of fatal crashes following this scenario.
Knowledgeable pilots avoid such traps by understanding the relationships between engine-out climb
performance and control. Optimum performance and minimum airspeed system errors both correspond to zero
sideslip. Directional control should be quite adequate at zero sideslip, unless the airspeed decays below
recommended values. Low speed rudder effectiveness can be improved at increased bank angles, but only at
substantial performance penalties.
Figure 5 depicts the tradeoffs between climb performance, rudder effectiveness, and directional control.
Condition 3 combines optimum performance with adequate directional control. Other bank angles offer no
competition. Figure 6 depicts the tradeoffs between climb performance and insurance against the stall/spin
28
hazard. Again, condition 3 combines the best performance achievable with greatest stall margin. Bank angles
beyond ZS only aggravate this grave hazard.
CONCLUSIONS
Pilot Operating Handbooks commonly misinform pilots regarding available engine-out climb performance and
how to obtain it. Perhaps the POH should contain "warning labels" similar to those on tobacco and alcohol
products! A naive pilot, convinced by POH calculations that he can climb, likely will attempt to do so. If the
pilot follows POH recommended bank angles greater than those corresponding to zero sideslip, the
performance deficit increases. Contrary to the pilot's expectation, combinations of equipment condition and
"overbank" guarantee that even the best climb rate is negative. See Figures 1 and 3.
Such attempts to achieve the unachievable climb will result in airspeed decay until control is lost. If the bank
angle is greater than approximately 2 degrees, a stall/spin is the likely result. If bank angle is too low,
directional control loss is probable when the vertical fin loses effectiveness before the dead engine wing stalls.
Figures 1 through 3 and Table I show the influence of bank angle on climb performance. Reference 1 provides
amplification and shows the performance difference between ZS and 5 degrees is equivalent to weight changes
in the 6-9% range.
Flight tests have shown that performance data in the POH are consistently optimistic, since service airplanes
seldom achieve charted climb performance. Table I is a small but sobering sample of actual deficits. The data
hint that airframe and engine time correlates with performance deterioration. Performance differences also
were observed between equal time engines on the same airframe. With airplanes flown per POH
recommendations, overall climb performance degradations as large as 181/6 gross weight equivalent were
measured. Fortunately, the degradations can be reduced approximately 90 FPM simply by maintaining the ZS
bank angle.
RECOMMENDATIONS
The pilot must realize his airplane and POH probably have characteristics similar to the samples cited. Once
the nature of the threat is grasped, the remedy is apparent. The informed pilot rejects the "Five Degree Forever
Syndrome" to climb at zero sideslip and achieve the best available performance. The prudent pilot will install a
yaw string to determine ZS bank angle and ball deflection for his airplane. Unless equipped with counter
rotating propellers flights should be done for both engines. See Reference 1 for details. For airplanes used
frequently for instruction, why not leave the yaw string installed?
Compare measured and POH-charted engine-out ROC for each engine. This can be done concurrently with the
ZS determinations above. One must determine airplane weight at the time of each test run, so a careful
calculation is necessary just before or after the test flight. ROC measurements should be made at zero sideslip
in smooth air. Measure altitude change over a 3-4 minute period at maximum continuous power on the
operating engine. Do not rely on the VSI. Conduct at least two runs per engine, preferably on reciprocal
headings. Record mid-test temperature and pressure altitude (29.92" set).
Compare measured results to the POH predictions for corresponding weight, temperature, and pressure
altitude. The differences represent "deltas," likely negative, which represent the particular airplane's climb
performance signatures. Each engine will have its individual delta, which can be expected to increase as flight
hours accumulate. The larger delta should be applied routinely to future POH climb tabulations as the
minimum safety factor applicable to ROC estimates.
As discussed in Reference 3, informed pilots also will recognize the likelihood of encountering conditions
rendering it impossible to hold altitude with a failed engine. So alerted, the pilot will sacrifice altitude as
required to conserve airspeed and maintain control. The only viable option in such cases may be a controlled
ditching. As one wag put it, "pick something soft and cheap and go for it." Compared to a 95% fatality rate in
29
stall/spin crashes, controlled forced landings of light twins are virtually 100% survivable. The 28-month
sample cited earlier showed 41 controlled ditchings, including several into trees, with a total of 106 occupants
involved. There were no fatal injuries and only 9% serious injuries. The remaining 91% experienced minor or
no injuries.
SUMMARY
Regardless of the number of engines involved, the pilot must remember the .maintain flying speed" maxim
learned before his first solo. Placing blind faith in the engine-out POH climb performance data and
recommended bank angles is hazardous to the health of pilots and passengers. Regular practice of engine-out
(feathered or zero thrust) conditions provides invaluable training. In such drills, marginal thrust-to-weight
conditions should be simulated by reducing power until performance conditions depicted in Figure 3, rather
than Figure 2, are achieved. One such experiment will demolish the Five Degree Forever Syndrome!
REFERENCE 1
Byington M.R. Jr. (1989, April) "Principles to Bank On." AOPA Flight Instructors Safety Report. Reprints
available in the pamphlet "Flying Light-Twin Engine Airplanes" for $1.75 from the AOPA Air Safety
Foundation (1-800-638-3101).
REFERENCE 2
Kelly, W.P. (1989) "Multi-Engine Stalls." The Aviation Consumer, June 1, 1989.
REFERENCE 3
Kelly, W.P. (1992) "When Twins Turn Nasty, Part L" Aviation Safety, Oct. 1, 1992.
Editors Note: Embry-Riddle Aeronautical University is offering for sale a videotape titled "Optimized EngineOut Procedures for Multi-Engine Airplanes" which parallels the information contained in Reference 1, price
$25 plus $3 for postage and handling (Florida residents add 6% sales tax). Send check or money order to
Embry-Riddle Aeronautical University, University Distribution Center, Daytona Beach FL 32114. Credit card
orders (VISA or MasterCard) accepted, call (904) 226-6484.
30
* Checkout in a Multiengine Airplane
(Excerpt from Advisory Circular 61-21A, Flight Training Handbook)
Modern design, engineering, and manufacturing technology have produced outstanding multiengine airplanes.
Their utility and acceptance have more than fulfilled the expectations of their builders. As a result of this rapid
development and increasing use, many pilots have found it necessary to make the transition from single-engine
airplane to those with two or more engines and complex equipment. Good basic flying habits formed during
earlier training, and carried forward to these new sophisticated airplanes, will make this transition relatively
easy, but only if the transition is properly directed.
The following paragraphs discuss several important operational differences which must be considered in
progressing from the simpler single-engine airplanes to the more complex multiengine airplanes.
1. Preflight Preparation. The complexity of multiengine airplanes demands the conduct of a more
systematic inspection of the airplane before entering the cockpit, and the use of a more complete and
appropriate checklist for each ground and flight operation.
Preflight visual inspections of the exterior of the airplane should be conducted in accordance with the
manufacturer's operating manual. The procedures set up in these manuals usually provide for a
comprehensive inspection, item by item in an orderly sequence, to be covered on a complete check of
the airplane. The transitioning pilot should have a thorough briefing in this inspection procedure, and
should understand the reason for checking each item.
2. Checklists. Essentially, all modern multiengine airplanes are provided with checklists, which may be
very brief or extremely comprehensive. A pilot who desires to operate a modern multiengine airplane
safely has no alternative but to use the checklist pertinent to that particular airplane. Such a checklist
normally is divided under separate headings for common operations, such as before starting. takeoff,
cruise, in-range, landing, system malfunctions, and engine-out operation.
The transitioning pilot must realize that multiengine airplanes characteristically have many more
controls, switches, instruments. and indicators. Failure to position or check any of these items may
have much more serious results than would a similar error in a single-engine airplane. Only definite
procedures. systematically planned and executed can ensure safe and efficient operation. The cockpit
checklist provided by the manufacturer in the operations manual must be used, with only those
modifications made necessary by subsequent alterations or additions to the airplane and its equipment.
In airplanes which require a copilot, or in which a second pilot is available, it is good practice for the
second pilot to read the checklist, and the pilot in command to check each increased item by actually
touching the control or device and repeating the instrument reading or prescribed control position in
question, under the careful observation of the pilot calling out the items on the checklist (Fig. 16-2).
Even when no copilot is present, the pilot should form the habit of touching, pointing to, or operating
each item as it is read from the checklist.
In the event of an in-flight emergency, the pilot should be sufficiently familiar with emergency
procedures to take immediate action instinctively to prevent more serious situations. However, as soon
as circumstances permit, the emergency checklist should be reviewed to ensure that all required items
have been checked.
3. Taxiing. The basic principles of taxiing which apply to single-engine airplanes are generally applicable
to multiengine airplanes. Although ground operation of multiengine airplanes may differ in some
respects from the operation of single-engine airplanes, the taxiing procedures also vary somewhat
between those airplanes with a nose wheel and those with a tailwheel-type landing gear. With either of
these landing gear arrangements. the difference in taxiing multiengine airplanes that is most obvious to
31
a transitioning pilot is the capability of using power differential between individual engines to assist in
directional control.
Tailwheel-type multiengine airplanes are usually equipped with tailwheel locks which can be used to
advantage for taxiing in a straight line especially in a crosswind. The tendency to weathervane can also
be neutralized to a great extent in these airplanes by using more power on the upwind engine, with the
tailwheel lock engaged and the brakes used as necessary.
On nose wheel-type multiengine airplanes. the brakes and throttles are used mainly to control the
momentum and steering done principally with the steerable nose wheel. The steerable nose wheel is
usually actuated by the rudder pedals, or in some airplanes by a separate hand-operated steering
mechanism.
No airplane should be pivoted on one wheel when making sharp turns, as this can damage the landing
gear. Tires, and even the airport pavement. All turns should be made with the inside wheel rolling,
even if only slightly.
Brakes may be used, as with any airplane, to start and stop turns while taxiing. When initiating a turn
though, they should be used cautiously to, prevent overcontrolling of the turn. Brakes should be used
as lightly as practicable while taxiing to prevent undue wear and heating of the brakes and wheels, and
possible loss of ground control. When brakes are used repeatedly or constantly they tend to heat to the
point that they may either lock or fail completely. Also, tires may be weakened or blown out by
extremely hot brakes. Abrupt use of brakes in multiengine as well as single-engine airplanes, is
evidence of poor pilot technique; it not only abuses the, airplane, but may even result in loss of
control.
Due to the greater weight of multiengine airplanes, effective braking is particularly essential.
Therefore, as the airplane begins to move forward when taxiing is started, the brakes should be tested
immediately by depressing each brake pedal. If the brakes are weak, taxiing should be discontinued
and the engines shut down.
Looking outside the cockpit while taxiing becomes even more important in multiengine airplanes.
Since these airplanes are usually somewhat heavier, larger, and more powerful than single-engine
airplanes they often require more time and distance to accelerate or stop, and provide a different
perspective for the pilot. While it usually is not necessary to make S-turns to observe the taxiing path,
additional vigilance is necessary to avoid obstacles, other aircraft, or bystanders.
4. Use of Trim Tabs. The trim tabs in a multiengine airplane serve the same purpose as in a single-engine
airplane, but their function is usually more important to safe and efficient flight. This is because of the
greater control forces, weight, power, asymmetrical thrust with one engine inoperative, range of
operating speeds, and range of center-of-gravity location. In some multiengine airplanes it taxes the
pilot's strength to overpower an improperly set elevator trim tab on takeoff or go-around. Many fatal
accidents have occurred when pilots took off or attempted a go-around with the airplane trimmed "full
nose up" for the landing configuration. Therefore, prompt retrimming of the elevator trim tab in the
event of an emergency go-around from a landing approach is essential to the success of the flight.
Multiengine airplanes should be retrimmed in flight for each change of attitude, airspeed, power
setting, and loading. Without such changes, constant application of firm forces on the flight controls is
necessary to maintain any desired flight attitude.
5. Normal Takeoffs. There is virtually little difference between a takeoff in a multiengine airplane and
one in a single-engine airplane. The controls of each class of airplane are operated the same; the
32
multiple throttles of the multiengine airplane normally are treated as one compact power control and
can be operated simultaneously with one hand.
In the interest of safety it is important that the flight. crew have a plan of action to cope with engine
failure during takeoff. It is recommended that just prior to takeoff the pilot in command review. or
brief the copilot on takeoff procedures. This briefing should consist of at least the engine out minimum
control speed, best all-engine rate of climb speed, best single-engine rate of climb speed, and what
procedures will be followed if an engine fails prior to reaching minimum control speed. This latter
speed is the minimum airspeed at which safe directional control can De maintained with one engine
inoperative and one engine operating at full power.
The multiengine (light twin) pilot's primary concern on all takeoffs is the attainment of the engine-out
minimum control speed prior to liftoff. Until this speed is achieved, directional control of the airplane
in flight will be impossible after the failure of an engine, unless power is reduced immediately on the
operating engine. If an engine fails before the engine-out minimum control speed is attained. THE
PILOT HAS NO CHOICE BUT TO CLOSE BOTH THROTTLES. ABANDON THE TAKEOFF.
AND DIRECT COMPLETE ATTENTION TO BRINGING THE AIRPLANE TO A SAFE STOP ON
THE GROUND.
The multiengine (light-twin) pilot's second concern on takeoff is the attainment of the single-engine
best rate-of-climb speed in the least amount of time. This is the airspeed which will provide the
greatest rate of climb when operating with one engine out and feathered (if possible), or the slowest
rate of descent. In the event of an engine failure, the single-engine best rate-of-climb speed must be
held until a safe maneuvering altitude is reached, or until a landing approach is initiated. When takeoff
is made over obstructions the best angle-of-climb speed should be maintained until the obstacles are
passed, then the best rate of climb maintained.
The engine-out minimum control speed and the single-engine be
st rate-of-climb speed are published in the airplane's FAA approved flight manual, or the Pilot's
Operating Handbook. These speeds should be considered by the pilot on every takeoff, and are
discussed in later sections of this chapter.
6. Crosswind Takeoffs. Crosswind takeoffs are performed in multiengine airplanes in basically the same
manner as those in single-engine airplanes. Less power may be used on the downwind engine to
overcome the tendency of the airplane to weathervane at the beginning of the takeoff, and then full
power applied to both engines as the airplane accelerates to a speed where better rudder control is
attained.
7. Stalls and Flight Maneuvers at Critically Slow Speeds. As with single-engine airplanes, the pilot
should be familiar with the stall and minimum controllability characteristics of the multiengine
airplane being flown. The larger and heavier airplanes have slower responses in stall recoveries and in
maneuvering at critically slow speeds due to their greater weight. The practice of stalls in multiengine
airplanes, therefore, should be performed at altitudes sufficiently high to allow recoveries to be
completed at least 3,000 feet above the ground.
It usually is inadvisable to execute full stalls in multiengine airplanes because of their relatively high
wing loading; therefore, practice should be limited to approaches to stalls (imminent), with recoveries
initiated at the first physical indication of the stall. As a general rule, however, full stalls in
multiengine airplanes are not necessarily violent or hazardous.
33
The pilot should become familiar with imminent stalls entered with various flap settings, power
settings, and landing gear positions. It should be noted that the extension of the landing gear will cause
little difference in the stalling speed, but it will cause a more rapid loss of speed in a stall approach.
Power-on stalls should be entered with both engines set at approximately 65 percent power. Takeoff
power may be used provided the entry speed is not greater than the normal lift-off speed. Stalls in
airplanes with relative low power loading using maximum climb power usually result in an excessive
nose-high attitude and make the recovery more difficult.
Because of possible loss of control, stalls with one engine inoperative or at idle power and the other
developing effective power are not to be performed during multiengine flight tests nor should they be
practiced by applicants for multiengine class ratings.
The same techniques used in recognition and avoidance of stalls of single-engine airplanes apply to
stalls in multiengine airplanes. The transitioning pilot must become. familiar with the characteristics
which announce an approaching or imminent stall, the indicated airspeed at which it occurs, and the
proper technique for recovery.
The increase in pitch attitude for stall entries should be gradual to prevent momentum from carrying
the airplane into an abnormally high nose-up attitude with a resulting deceptively low indicated
airspeed at the time the stall occurs. It is recommended that the rate of pitch change result in a 1 knotper-second decrease in airspeed. In all stall recoveries the controls should be used very smoothly,
avoiding abrupt pitch changes. Because of high gyroscopic stresses, this is particularly true in
airplanes with extensions between the engines and propellers.
Smooth control manipulation is particularly a requisite of flight at minimum or critically slow
airspeeds. As with all piloting operations, a smooth technique permits the development of a more
sensitive feel of the controls with a keener sense of stall anticipation. Flight at minimum or critically
slow airspeeds gives the pilot an understanding of the relationship between the attitude of an airplane,
the feel of its control reactions and the approach to an actual stall.
Generally, the technique of Right at minimum airspeeds, is the same in a multiengine airplane as it is
in a single-engine airplane. Because of the additional -equipment in the multiengine airplane, the
transitioning pilot has more to do and observe, and the usually slower control reaction requires better
anticipation. Care must be taken to observe engine temperature indications for possible overheating,
and to make necessary power adjustments smoothly on both engines at the same time.
8. Approaches and Landings. Multiengine airplanes characteristically have steeper gliding angles
because of their relatively high wing loading, and greater drag of wing flaps and landing gear when
extended. For this reason, power is normally used throughout the approach to shallow the approach
angle and prevent a high rate of sink.
The accepted technique for making stabilized landing approaches is to reduce the power to a
predetermined setting during the arrival descent so the appropriate landing aflar extension speed will
be attained in level flight as the downwind leg of the approach pattern is entered (Fig. 16-3). With this
power setting, the extension of the landing grear (when the airplane is on the downwind leg opposite
the intended point of touchdown) will further reduce the airspeed to the desired traffic pattern
airspeed. The manufacturer's recommended speed should be used throughout the pattern. When
practicable, however, the speed should be compatible with other air traffic in the traffic pattern. When
within the maximum speed for flap extension, the flaps may be partially lowered if desired, to aid in
reducing the airspeed to traffic pattern speed. The angle of bank normally should not exceed 300 while
turning onto the legs of the traffic pattern.
34
The prelanding checklist should be completed by the time the airplane is on base leg so that the pilot
may direct full attention to the approach and landing. In a power approach, the airplane should
descend at a stabilized rate, allowing the pilot to plan and control the approach path to the point of
touchdown. Further extension of the flaps and slight adjustment of power and pitch should be
accomplished as necessary to establish and maintain a stabilized approach path. Power and pitch
changes during approaches should in all cases he smooth and gradual.
The airspeed of the final approach should be as recommended by the manufacturer; if a recommended
speed is not furnished, the airspeed should be not less than the engine-out best rate-of-climb speed
(Vyse) until the landing is assured, because that is the minimum speed at which a single-engine goaround can be made if necessary. IN NO CASE SHOULD THE APPROACH SPEED BE LESS
THAN THE CRITICAL ENGINE-OUT MINIMUM CONTROL SPEED. If an engine should fail
suddenly and it is necessary to make a go-around from a final approach at less than that speed, a
catastrophic loss of control could occur. As a rule of thumb, after the wing flaps are extended the final
approach speed should be gradually reduced to 1.3 times the power-off stalling speed (1.3 Vso).
The round out or flare should be started at sufficient altitude to allow a smooth transition from the
approach to the landing attitude. The touchdown should be smooth, with the airplane touching down
on the main wheels and the airplane in a tail-low attitude, with or without power as desired. The actual
attitude at touchdown is very little different in nose wheel- and tail wheel-type airplanes. Although
airplanes with nose wheels should touch down in a tail-low attitude, it should not be so low as to drag
the tail on the runway. On the other hand, since the nose wheel is not designed to absorb the impact of
the full weight of the airplane, level or nose-low attitudes must be avoided.
Directional control on the rollout should be accomplished primarily with the rudder and the steerable
nose wheel, with discrete use of the brakes applied only as necessary for crosswinds or other factors.
9. Crosswind Landings. Crosswind landing technique in multiengine airplanes is very little different
from that required in single-engine airplanes. The only significant difference lies in the fact that
because of the greater weight, more positive drift correction must be maintained before the
touchdown.
It should be remembered that FAA requires that most airplanes have satisfactory control capabilities
when landing in a direct crosswind of not more than 20 percent of the stall speed (0.2 Vso). Thus, an
airplane with a power-off stalling speed of 60 knots has been designed for a maximum direct
crosswind of 12 knots (.2 x 60) on landings. Though skillful pilots may successfully land in much
stronger winds, poor pilot technique is apt to cause serious damage in even more gentle winds. Some
light and medium multiengine airplanes have demonstrated satisfactory control with crosswind
components greater than .2 Vso. If this has been done it will be noted in the Pilot's Operating
Handbook under operations limitations.
The two basic methods of making crosswind landings, the slipping approach (wing-low) and the
crabbing approach may be combined. These are discussed in the chapter on Approaches and
Landings.
The essential factor in all crosswind landing procedures is touching down without drift, with the
heading of the airplane parallel to its direction of motion. This will result in minimum side loads on
the landing gear.
10. Go-Around Procedure. The complexity of modern multiengine airplanes makes a knowledge of and
proficiency in emergency go-around procedures particularly essential for safe piloting. The emergency
35
go-around during a landing approach is inherently critical because it is usually initiated at a very low
altitude and airspeed with the airplane's configuration and trim adjustments set for landing.
Unless absolutely necessary, the decision to go around should not be delayed to the point where the
airplane is ready to touch down (Fig. 16-4). The more altitude and time available to apply power.,
establish a climb, retrim, and set up a go-around configuration. the easier and safer the maneuver
becomes. When the pilot has decided to go around, immediate action should be. taken without
hesitation, while maintaining positive control and accurately following the manufacturer's
recommended procedures.
Go-around procedures vary with different airplanes, depending on their weight, flight characteristics, flap and
retractable gear Systems, and flight performance. Specific procedures must be learned by the transitioning
pilot from the Pilot's Operating Handbook, which should always be available in the cockpit.
There are several general go-around procedures which apply to most airplanes, and are worth pointing out:
a. When the decision to go around is reached, takeoff power should be applied immediately and the
descent stopped by adjusting the pitch attitude to avoid further loss of altitude.
b. The flaps should be retracted only in accordance with the procedure prescribed in the airplane's
operating manual. Usually this will require the flaps to be positioned as for takeoff.
c. After a positive rate of climb is established the landing gear should be retracted, best rate-of-climb
airspeed obtained and maintained, and the airplane trimmed for this climb. The procedure for a normal
takeoff climb should then be followed.
The basic requirements of a successful go-around, then, are the prompt arrest of the descent, and the
attainment and maintenance of the best rate-of-climb airspeed.
At any time the airspeed is faster than the flaps-up stalling speed, the flaps may be retracted
completely without losing altitude if simultaneously the angle of attack is increased sufficiently. At
critically slow airspeeds, however, retracting the flaps prematurely or suddenly can cause a stall or an
unanticipated loss of altitude. Rapid or premature retraction of the flaps should be avoided on goarounds, especially when close to the ground, because of the careful attention and exercise of precise
pilot technique necessary to prevent a sudden loss of altitude. It generally will be found that retracting
the flaps only halfway or to the specified approach setting decreases the drag a relatively greater
amount than it decreases the lift.
The FAA approved Airplane Flight Manual or Pilot's Operating Handbook should be consulted
regarding landing gear and flap retraction procedures because in some installations simultaneous
retraction of the gear and flaps may increase the flap retraction time, and full flaps create more drag
than the extended landing gear.
Light-Twin Performance Characteristics
From the transitioning pilot's point of view. the basic difference between a light-twin and single-engine
airplane is the potential problem involving engine failure. The information that follows is confined to that one
basic difference.
The term "light-twin" as used here pertains to the propeller driven airplane having a maximum certificated
gross weight of less than 12,500 pounds, and which has two reciprocating engines mounted on the wings.
Before the subject of operating technique in light twin-engine airplanes can be thoroughly discussed, there are
several terms that need to be reviewed. "V" speeds such as Vx, Vxe, Vy, Vyse, and Vmc are the main
performance speeds the light-twin pilot needs to know in addition to the other performance speeds common to
both twin-engine and single-engine airplanes. The airspeed indicator in twin-engine airplanes is marked (in
36
addition to other normally marked speeds) with a red radial line at the minimum controllable airspeed with the
critical engine inoperative, and a blue radial line at the best rate-of-climb airspeed with one engine inoperative
(Fig. 16-5).
Vx — The speed for best angle of climb. At this speed the airplane will gain the greatest height, for it. given
distance of forward travel. This speed is used for obstacle clearance with all engines operating. However, this
speed is different when one engine is inoperative. and in this handbook is referred to as Vxse (single-engine).
Vy — The speed for the best rate of climb. This speed will provide the maximum altitude gain for a given
period of time with all engines operating. However, this speed too will be different when one engine is
inoperative and in this handbook is referred to as Vyse (single-engine).
Vmc — The minimum control speed with the critical engine inoperative. The term Vmc can be defined as the
minimum airspeed at which the airplane is controllable when the critical engine is suddenly made inoperative,
and the remaining engine is producing takeoff power. The Federal Aviation Regulations under which the
airplane was certificated, stipulate that at Vmc the certificating test pilot must be able to: (1) stop the turn
which results when the critical engine is suddenly made inoperative within 20 degrees of the original heading,
using maximum rudder deflection and a maximum of 5 degrees bank into the operative engine, and (2) after
recovery, maintain the airplane in straight flight with not more than a 5 degree bank (wing lowered toward the
operating engine). This does not mean that the airplane must be able to climb or even hold altitude. It only
means that a heading can be maintained. The principle of Vmc is not at all mysterious. It is simply that at any
airspeed less than Vmc, air flowing along the rudder is such that application of rudder forces cannot overcome
the asymmetrical yawing forces caused by takeoff power on one engine and it powerless windmilling propeller
on the other. The demonstration of Vmc is discussed in a later section of this handbook.
Many pilots erroneously believe that because a light-twin has two engines, it. will continue to perform at least
half as well with only one of those engines operating. There is nothing in FAR Part 23, governing the
certification of light-twins, which requires an airplane to maintain altitude while in the takeoff configuration
and with one engine inoperative. In fact, many of the current light-twins are not required to do this with one
engine inoperative in any configuration, even at. sea level. This is of major significance in the operations of
light-twins certificated under Part -23. With regard to performance (but not controllability) in the takeoff or
landing configuration, the light twin-engine airplane is, in concept, merely a single-engine airplane with its
power divided into two individual units. The following discussion should help the pilot to eliminate any
misconceptions of single-engine operation of light-twin airplanes.
When one engine fails on a light-twin, performance is not really halved, but is actually reduced by 80 percent
or more. The performance loss is greater than 50 percent because an airplane's climb performance is a function
of the thrust horsepower which is in excess of that required for level flight. When power is increased in both
engines in level flight and the airspeed is held constant, the airplane will start climbing — the rate of climb
depending on the power added (which is power in excess of that required for straight-and-level flight). When
one engine fails. However, it not only loses power but the drag increases considerably because of asymmetric
thrust and the operating engine must then carry the full burden alone. To do this, it must produce 75 percent or
more of its rated power. This leaves very little excess power for climb performance.
As an example, an airplane which has an all-engine rate of climb of 1.860 FPM and a single engine rate of
climb of 190 FPM would lose almost 90 percent of its climb performance when one engine fails.
Nonetheless. the light-twin does offer obvious safety advantages over the single-engine airplane (especially in
the enroute phase) but only if the pilot fully understands the real options offered by that second engine in the
takeoff and approach phase of flight.
37
It is essential then that the light-twin pilot take proficiency training periodically from a competent flight
instructor.
Engine-Out Emergencies
In general, the operating and flight characteristics of modern light-twins with one engine inoperative are
excellent. Them airplanes can be controlled and maneuvered safely as long as sufficient airspeed is
maintained. However, to utilize the safety and performance characteristics effectively, the pilot must have a
sound understanding of the single-engine performance and the limitations resulting from an unbalanced of
power.
A pilot checking out for the first time in any multiengine airplane should practice and become thoroughly
familiar with the control and performance problems which result from the failure of one engine during any
flight condition. Practice in all the control operations and precautions is necessary and demonstration of these
is required on multiengine rating flight tests. Practice should be continued as long as the pilot engages in flying
a twin-engine airplane, so that corrective action will be instinctive and the ability to control airspeed, heading,
and altitude will be retained.
The feathering of a propeller should be demonstrated and practiced in all airplanes equipped with propellers
which can be feathered and unfeathered safely in flight. If the airplane used is not equipped with feathering
propellers, or is equipped with propellers, which cannot be feathered and unfeathered safely in flight, one
engine should be secured (shut down) in accordance with the procedures in the FAA approved Airplane Flight
Manual or the Pilot's Operating Handbook. The recommended propeller setting should be used, and the
emergency setting of all ignition. electrical, hydraulic, and fire extinguisher systems should be demonstrated.
Propeller Feathering
When an engine fails in flight the movement of the airplane through the air tends to keep the propeller rotating,
much like a windmill. Since the failed engine is no longer delivering power to the propeller to produce thrust
but instead, may be absorbing energy to overcome friction and compression of the engine, the drag of the
windmilling propeller is significant and causes the airplane to yaw toward the failed engine (Fig. 16-6). Most
multiengine airplanes are equipped with "full-feathering propellers" to minimize that yawing tendency.
The blades of a feathering propeller may be positioned by the pilot to such a high angle that they are
streamlined in the direction of flight. In this feathered position, the blades act as powerful brakes to assist
engine friction and compression in stopping the windmilling rotation of the propeller. This is of particular
advantage in case of a damaged engine, since further damage, caused by a windmilling propeller creates the
least possible drag on the airplane and reduces the yawing tendency. As a result, multiengine airplanes are
easier to control in flight when the propeller of an inoperative engine is feathered.
Feathering of propellers for training and checkout purposes should be performed only under such conditions
and at such altitudes and locations that a safe landing on an established airport could be accomplished readily
in the event of difficulty in unfeathering the propeller.
Engine-Out Procedures
The following procedures are recommended to develop in the transitioning pilot the habit of using proper
procedures and proficiency in coping with an inoperative engine.
At a safe altitude (minimum 3,000 feet above terrain) and within landing distance of a suitable airport, an
engine may be shut down with the mixture control or fuel selector. At lower altitudes, however, shut down
should be simulated by reducing power by means of the throttle to the zero thrust setting. The following
procedures should then be followed:
1. Set mixture and propeller controls as required; both power controls should be positioned for maximum
power to maintain at least Vmc.
38
2.
3.
4.
5.
6.
7.
Retract wing flaps and landing gear.
Determine which engine failed, and verify it by closing the throttle on the dead engine.
Bank at least 5 degrees into the operative engine.
Determine the cause of failure, or feather the inoperative engine.
Turn toward the nearest airport.
Secure (shut down) the inoperative engine in accordance with the manufacturer's approved procedures
and check for engine fire.
8. Monitor the engine instruments on the operating engine; and adjust power, cowl flaps, and airspeed as
necessary.
9. Maintain altitude and an airspeed of at least Vyse if possible.
The pilot must be proficient in the control of heading, airspeed, and altitude, in the prompt identification of a
power failure, and in the accuracy of shutdown and restart procedures as prescribed in the FAA approved
Airplane Flight Manual or Pilot's Operating Handbook.
There is no better way to develop skill in single-engine emergencies than by continued practice. The fact that
the techniques and procedures of single-engine operation are mastered thoroughly at one time during a pilot's
career is no assurance of being able to cope successfully with an engine-out emergency unless review and
practice are continued. Some engine-out emergencies may be so critical that there may be no safety margin for
lack of skill or knowledge. Unfortunately, many light-twin pilots never practice single-engine operation after
receiving their multiengine rating.
The pilot should practice and demonstrate the effects (on engine-out performance) of various configurations of
gear, flaps, and both; the use of carburetor heat; and the failure to feather the propeller on an inoperative
engine. Each configuration should be maintained, at best engine-out rate-of-climb speed long enough to
determine its effect on the climb (or sink) achieved. Prolonged use of carburetor heat, if so equipped, at high
power settings should be avoided.
The Critical Engine
"P-factor" is present in multiengine airplanes just as it is in single-engine airplanes. Remember, P-factor is
caused by the dissimilar thrust of the rotating propeller blades when in certain flight conditions. It is the result
of the downward moving blade having a greater angle of attack than the upward moving blade when the
relative wind striking the blades is not aligned with the thrust line (as in a nose-high attitude).
In most U.S. designed light-twins, both engines rotate to the right (clockwise) when viewed from the rear, and
both engines develop an equal amount of thrust. At low airspeed and high power conditions, the downward
moving propeller blade of each engine develops more thrust than the upward moving blade. This asymmetric
propeller thrust or "P-factor," results in a center of thrust at the right side of each engine as indicated by lines
D1 and D2 in Fig. 16-7. The turning (or yawing) force of the right engine is greater than the left engine
because the center of thrust (D2) is much farther away from the center line (CL) of the fuselage-it has a longer
level arm. Thus, when the right engine is operative and the left engine is inoperative, the turning (or yawing)
force is greater thin in the opposite situation of a "good" left engine and a "bad" right engine. In other words,
directional control may be difficult when the left engine (the critical engine) is suddenly made inoperative.
It should be noted that some light-twin engine airplanes are equipped with engines turning in opposite
directions; that is, the left engine and propeller turn clockwise and the right engine and propeller turn
counterclockwise. With this arrangement, the thrust line of either engine is the same distance from the center
line of the fuselage, so there will be no difference in yaw effect between loss of left or right engine.
Vmc Demonstrations
Every light-twin engine airplane checkout should include a demonstration of the airplane's engine-out
minimum control speed. The engine-out minimum control speed given in the FAA approved Airplane Flight
39
'Manual. Pilot's Operating Handbook, or other manufacturer's published limitations is determined during
original airplane certification under conditions specified in the Federal Aviation Regulations. These conditions
normally are not duplicated during pilot training or testing because, they consist of the most adverse situations
for airplane type certification purposes. Prior to a pilot checkout, a thorough discussion of the factors affecting
engine-out minimum control speed is essential.
Basically, when one engine fails the pilot must overcome the asymmetrical thrust (except on airplanes with
center line thrust) created by the operating engine by setting up a counteracting moment with the rudder. When
the rudder is fully deflected. its yawing power will depend on the velocity of airflow across the rudder-which
in turn is dependent on the airspeed. As the airplane decelerates it will reach a speed below which the rudder
moment will no longer balance the thrust moment and directional control will be lost.
During engine-out flight the large rudder deflection required to counteract the asymmetric thrust also results in
a "lateral lift" force on the vertical fin. This lateral "lift" represents an unbalanced side force on the airplane
which must be counteracted either by allowing the airplane to accelerate sideways until the lateral drag caused
by the sideslip equals the rudder "lift" force or by banking into the operative engine and using a component of
the airplane weight to counteract the rudder-induced side force.
In the first case, the wings will be level, the ball in the turn-and-slip indicator will be centered and the airplane
will be in a moderate sideslip toward the inoperative engine. In the second case, the wings will be banked 3-5
degrees into the good engine, the ball will be deflected one diameter toward the operative engine, and the
airplane will be at zero sideslip.
The sideslipping method has several major disadvantages: (1) the relative wind blowing on the inoperative
engine side of the vertical fin tends to increase the asymmetric moment caused by the failure of one engine; (2)
the resulting sideslip severely degrades stall characteristics; and (3) the greater rudder deflection required to
balance the extra moment and the sideslip drag cause a significant reduction in climb and/or acceleration
capability.
Flight tests have shown that holding the ball of the turn-and-slip indicator in the center while maintaining
heading with wings level drastically increases Vmc as much as 20 knots in some airplanes. (Remember, the
value of Vmc given in the FAA approved flight manual for the. airplane is based on a maximum 5 degree bank
into the operative engine.) Banking into the operative engine reduces Vmc, whereas decreasing the bank angle
away from the operative engine increases Vmc at the rate of approximately 3 knots per degree of bank angle.
Flight tests have also shown that the high drag caused by the wings level, ball centered configuration can
reduce single-engine climb performance by as much as 300 FPM, which is just about all that is available at sea
level in a non-turbocharged light twin.
Banking at least 5 degrees into the good engine ensures that the airplane will be controllable at any speed
above the certificated Vmc, that the airplane will be in a minimum drag configuration for best climb
performance, and that the stall characteristics will not be degraded. Engine-out flight with the ball centered is
never correct.
The magnitude of these effects will vary from airplane to airplane, but the principles are applicable in all cases.
NOTE. — A bank limitation of up to 5 degrees during demonstration is applicable only to certification tests of
the airplane and is not intended as a limit in training or testing a pilot's ability to extract maximum
performance from the airplane.
For an airplane with non-supercharged engines, Vmc decreases as altitude is increased. Consequently,
directional control can be maintained at a lower airspeed than at sea level. The reason for this is that, since
40
power decreases with altitude the thrust, moment of the operating engine becomes less, thereby lessening the
need for the rudder's yawing force. Since V., is a function of power (which decreases with altitude). it is
possible for the airplane to reach a stall speed prior to loss of directional control.
It must be understood, therefore., that there is a certain density altitude above which the stalling speed is
higher than the engine-out minimum control speed. When this density altitude exists close to the ground
because of high elevations or temperatures, an effective flight demonstration is impossible and should not be
attempted. When a flight demonstration is impossible, the check pilot should emphasize orally the significance
of the engine-out minimum control speed, including the results of attempting flight below this speed with one
engine inoperative, the recognition of the imminent loss of control, and the recovery techniques involved.
Vmc is greater when the center of gravity is at the rearmost allowable position. Since the airplane rotates
around its center of gravity. the moments are measured using that point as a reference. A rearward CG would
not affect the thrust moment, but would shorten the arm to the center of the rudder's horizontal "lift" which
would mean that a higher force (airspeed) would be required to counteract the engine-out yaw. Figure 16-8
shows an exaggerated view of the effects of a rearward CG.
Generally, the center of gravity range of most light twins is short enough so that the effect on the Vmc is
relatively small, but it is a factor that should be considered. Many pilots would only consider the rear CG of
their light-twin as a factor for pitch stability, not realizing that it could affect the controllability with one
engine out.
There are many light-twin pilots who think that the only control problem experienced in flight below Vmc is a
yaw toward the inoperative engine. Unfortunately, this is not the whole story.
With full power applied to the operative engine, as the airspeed drops below Vmc, the airplane tends to roll as
well as yaw into the inoperative engine. This tendency becomes greater as the airspeed is further reduced,
since this tendency must be counteracted by aileron control, the yaw condition is aggravated by aileron yaw
(the "down" aileron creates more drag than the "up" aileron). If a stall should occur in this condition, a violent
roll into the dead engine may be experienced. Such an event occurring close to the ground could be disastrous.
This may be avoided by maintaining airspeed above at all times during single-engine operation. If the airspeed
should fall below Vmc — for whatever reason — then power must be reduced on the operative engine and the
airplane must be banked at least 5 degrees toward the operative engine if the airplane is to be safely
controlled.
The Vmc demonstrations should be performed at an altitude from which recovery from loss of control could
be made safely. One demonstration should be made while holding the wings level and the ball centered, and
another demonstration should be made while banking the airplane at least 5 degrees toward the operating
engine to establish "zero sideslip." These maneuvers will demonstrate the engine-out minimum control speed
for the existing conditions and will emphasize the necessity of banking into the operative engine. No attempt
should be made to duplicate Vmc as determined for airplane certification.
After the propellers are set to high RPM, the landing gear is retracted, and the flaps are in the takeoff position,
the airplane should be placed in a climb attitude and airspeed representative of that following a normal takeoff.
With both engines developing as near rated takeoff power as possible, power on the critical engine (usually the
left) should then be reduced to idle (windmilling, not shut down). After this is accomplished, the airspeed
should be reduced slowly with the elevators until directional control no longer can be maintained. At this
point, recovery should be initiated by simultaneously reducing power on the operating engine and reducing-the
angle of attack by lowering the nose. Should indications of a stall occur prior to reaching this point, recovery
should be initiated immediately by reducing the angle of attack. In this case, a minimum engine-out control
speed demonstration is not possible under existing conditions.
41
If it is found that the minimum engine-out control speed is reached before indications of a stall are
encountered, the pilot should demonstrate the ability to control the airplane and initiate a safe climb in the
event of a power failure at the published engine-out minimum control speed.
Accelerate/Stop Distance
The most critical time for an engine-out condition in a twin-engine airplane is during the two or three-second
period immediately following the takeoff roll while the airplane is accelerating to a safe engine-failure speed.
Although most twin-engine airplanes are controllable at a speed close to the engine-out minimum control
speed, the performance is often so far below optimum that continued flight, following takeoff may be marginal
or impossible. A more suitable recommended speed, termed by some aircraft manufacturers as minimum safe
single-engine speed, is that at which altitude can be maintained while the landing gear is being retracted and
the propeller is being feathered.
Upon engine failure after reaching the safe single-engine speed on takeoff, the twin-engine pilot (having lost
one-half of the normal power) usually has a significant advantage over the pilot of a single-engine airplane,
because, if the particular airplane has single-engine climb capability at the existing gross weight and density
altitude, there may be the choice of stopping or continuing the takeoff. This compares with the only choice
facing a single-engine airplane pilot who suddenly has lost half of the normal takeoff power — that is stop!
If one engine fails prior to reaching Vmc, there is no choice but to close both throttles and bring the airplane to
a stop. If engine failure occurs after becoming airborne, the pilot must decide immediately to land or to
continue the takeoff.
If the decision is made to continue the takeoff, the airplane must be able to gain altitude with one engine
inoperative. This requires acceleration to Vyse if no obstacles are involved, or to Vxse if obstacles are a factor.
To make a correct decision in an emergency of this type, the pilot must consider the runway length, field
elevation, density altitude, obstruction height, headwind component, and the airplane's gross weight. (For
simplification purposes, additional factors such as runway contaminants [rubber, soot, water, ice, snow] and
runway slope will not be discussed here.) The flight paths illustrated in Fig. 16-9 indicate that the "area of
decision" is bounded by: (1) the point at which Vy is reached and (2) the point where the obstruction altitude is
reached. An engine failure in this area demands an immediate decision. Beyond this decision area, the
airplane, within the limitations of engine-out climb performance, can usually be maneuvered to a landing at the
departure airport.
The "accelerate-stop distance" is the total distance required to accelerate the twin-engine airplane to a specified
speed and, assuming failure of an engine at the instant that speed is attained, to bring the airplane to a stop on
the remaining runway. The "accelerate-go distance" is the total distance required to accelerate the airplane to a
specified speed and, assuming failure of an engine at the instant that speed is attained, continue takeoff on the
remaining engine to a height of 50 feet.
For example, use the chart in Fig. 16-10 and assume that with a temperature of 80 degrees F., a calm wind at a
pressure altitude of 2,000 feet, a gross weight of 4,800 pounds, and all engines operating, the airplane being
flown requires 3,525 feet to accelerate to 105 MPH and then be brought to a stop. Assume also that the
airplane under the same conditions requires a distance of 3,830 feet to take off and climb over a 50-foot
obstacle (Fig. 16-11) when one engine fails at 105 MPH.
With such a slight margin of safety (305 feet) it would be better to discontinue the takeoff and stop if the
runway is of adequate length, since any slight mismanagement of the engine-out, procedure would more than
outweigh the small advantage offered by continuing the takeoff. At higher field elevations the advantage
becomes less and less until at very high density altitudes a successful continuation of the takeoff is extremely
improbable.
42
Factors in Takeoff Planning
Competent pilots of light-twins will plan the takeoff in sufficient detail to be able to take immediate action if
and-when one engine tails during the takeoff process. They will be thoroughly familiar with the airplane's
performance capabilities and limitations, including accelerate-stop distance, as well as the distance available
for takeoff, and will include such factors in their plan of action. For example, if it has been determined that the
airplane cannot maintain altitude with one engine inoperative (considering the gross weight and density
altitude), the seasoned pilot will be well aware that should an engine fail right after lift-off, an immediate
landing may have to be made in the most suitable area available. The competent pilot will make no attempt to
maintain altitude at the expense of a safe airspeed.
Consideration will also be given to surrounding terrain, obstructions., and nearby landing areas so that a
definite direction of flight can be established immediately if an engine fails at, a critical point during the climb
after takeoff. It is imperative then, that the takeoff and climb path be planned so that all obstacles between the
point of takeoff and the available areas of landing can be cleared if one engine suddenly becomes inoperative.
In addition, a competent light-twin pilot knows that the twin-engine airplane must be flown with precision if
maximum takeoff performance and safety are to be obtained. For example, the airplane must lift off at a
specific airspeed, accelerate to a definite climbing airspeed, and climb with maximum permissible power on
both engines to a safe single-engine maneuvering altitude. In the meantime, if an engine fails. a different
airspeed must be attained immediately. This airspeed must be held precisely because only at this airspeed will
the pilot be able to obtain maximum performance from the airplane. To understand the factors involved in
proper takeoff planning, a, further explanation of this critical speed follows, beginning with the lift-off.
The light-twin can be controlled satisfactorily while firmly on the ground when one engine fails prior to
reaching Vmc during the takeoff roll. This is possible by closing both throttles, by proper use of rudder and
brakes, and with many airplanes by use of nosewheel steering. If the airplane is airborne at less than Vmc,
however, and suddenly loses all power on one engine, it cannot be controlled satisfactarily. Thus, on normal
takeoffs, lift-off should never take place until the airspeed reaches and exceeds Vmc. The FAA recommends a
minimum speed of Vmc plus 5 knots before lift-off. From this point, an efficient climb procedure should be
followed (Fig. 16-12).
An efficient climb procedure, is one in which the airplane leaves the ground slightly above Vmc, accelerates
quickly to Vy (best rate-of-climb speed) and climbs at Vy. The climb at Vy should be made with both engines
set to maximum takeoff power until reaching a safe single-engine maneuvering altitude (minimum of
approximately 500' above field elevation or as dictated by airplane performance capability and/or local
obstacles). At this point, power may be reduced to the allowable maximum continuous power setting (METO
— maximum except takeoff) or less, and any desired enroute climb speed then may be established. The
following discussion explains why Vy is recommended for the initial climb.
To improperly trained pilots, the extremes in takeoff technique may suggest "hold it down" to accelerate the
airplane to near cruise speed before climbing, or "pull it off" below Vmc and climb as steeply as possible. If
one considers the possibility of an engine failure somewhere during the takeoff, neither of these procedures
makes much sense for the following reasons: Remember, drag increases as the square of the speed; so for any
increase in speed over and above the best rate-of-climb speed, Vy, the greater the drag and the less climb
performance the airplane will have. At 123 knots the drag is approximately one and one-half times greater than
it is at 100 knots. At 141 knots the drag is doubled, and at 200 knots the drag is approximately four times as
great as at 100 knots. While the drag is increasing as the square of the velocity (V2), the power required to
maintain a velocity increases as the cube of that velocity (V3).
In the event of engine failure, a pilot who uses excessive speed on takeoff will discover suddenly that all the
energy produced by the engines has been converted into speed. Improperly trained pilots often believe that the
43
excess speed can always be converted to altitude, but this theory is not valid. Available power is only wasted
in accelerating the airplane to an unnecessary speed. Also, experience has shown that an unexpected engine
failure so surprises the unseasoned pilot that proper reactions are extremely lagging. By the time the initial
shock wears off and the pilot is ready to take control of the situation, the excess speed has dissipated and the
airplane is still barely off the ground. From this low altitude, the pilot would still have to climb, with an engine
inoperative, to whatever height is needed to clear all obstacles and get back to the approach end of the runway.
Excess speed cannot be converted readily to the altitude or distance necessary to reach a landing area safely.
In contrast, however, an airplane will fly in level flight much easier than it will climb. Therefore, if the total
energy of both engines is initially converted to enough height above the ground to permit clearance of all
obstacles while in level flight (safe maneuvering altitude), the problem is much simpler in the event an engine
fails. If some extra height is available, it usually can be traded for velocity or gliding distance when needed.
Simply stated then, altitude is more essential to safety after takeoff than is excess airspeed. On the other hand,
trying to gain height too fast, in the takeoff also can be very dangerous because of control problems. If the
airplane has just become airborne and the airspeed is at or below Vmc when an engine fails, the pilot could
avoid a serious accident by retarding both throttles immediately. If this action is not taken immediately, the
pilot will be unable to control the airplane.
Consequently, the pilot always should keep one hand on the control wheel (when not operating handcontrolled nose steering) and the other hand on the throttles throughout the takeoff roll. The airplane should
remain on the ground until adequate speed is reached so that a smooth transition to the proper climb speed can
be made. THE AIRPLANE SHOULD NEVER LEAVE THE GROUND BEFORE Vmc IS REACHED.
Preferably, Vmc + 5 knots should be attained.
If an engine fails before leaving the ground it is advisable to discontinue the takeoff and STOP. If an engine
fails after lift-off, the pilot will have to decide immediately whether to continue flight, or to close both throttles
and land. However, waiting until the engine failure occurs is not the time for the pilot to plan the correct
action. The action must be planned before the airplane is taxied onto the runway. The plan of action must
consider the density altitude, length of the runway, weight of the airplane, and the airplane's accelerate-stop
distance, and accelerate-go distance under these conditions. Only on the basis of these factors can the pilot
decide intelligently what course to follow if an engine should fail. When the flight crew consists of two pilots,
it is recommended that the pilot in command brief the second pilot on what course of action will be taken
should the need arise.
To reach a safe single-engine maneuvering altitude as safely and quickly as possible, the climb with all
engines operating -must be made at the proper airspeed. That speed should provide for:
1. Good control of the airplane in case an engine fails.
2. Quick and easy transition to the single-engine best rate-of-climb speed if one engine fails.
3. A fast rate of climb to attain an altitude which permits adequate time for analyzing the situation and
making decisions.
To make a quick and easy transition to the single-engine best rate-of-climb speed, in case an engine fails, the
pilot should climb at some speed greater than Vyse. If an engine fails at less than Vyse, it would be necessary
for the pilot to lower the nose to increase the speed to Vyse in order to obtain the best climb performance. If
the airspeed is considerably less than this speed, it might be necessary to lose valuable altitude to increase the
speed to Vyse. Another factor to consider is the loss of airspeed that may occur because of erratic pilot
technique after a sudden, unexpected power loss. Consequently, the normal initial two-engine climb speed
should not be less than Vy.
In summary then, the initial climb speed for a normal takeoff with both engines operating should permit the
attainment of a safe single-engine maneuvering altitude as quickly as possible; it should provide for good
44
control capabilities in the event of a sudden power loss on one engine; and it should be a speed sufficiently
above Vyse to permit attainment of that speed quickly and easily in the event power is suddenly lost on one
engine. The only speed that meets all of these requirements for a normal takeoff is the best rate-of-climb speed
with both engines operating (Vy).
Normal Takeoff — Both Engines Operating
After run up and pre-takeoff checks have been completed, the airplane should be taxied into takeoff position
and aligned with the runway. If it is a tailwheel-type, the tailwheel lock (if installed) should be engaged only
after the airplane has been allowed to roll straight a few feet along the intended takeoff path to center the
tailwheel.
If the crew consists of two pilots, it is recommended that the pilot in command brief the other pilot on takeoff
procedures prior to receiving clearance for takeoff. This briefing consists of at least the following: minimum
control speed (Vmc), rotation speed (Vr), liftoff speed (Vlof), single-engine best rate-of-climb speed (Vyse),
all engine best rate-of -climb speed (Vy), and what procedures will be followed if an engine failure occurs
prior to Vmc (Fig. 16-12).
Both throttles then should be advanced simultaneously to takeoff power, and directional control maintained by
the use of the steerable nose wheel and the rudder. Brakes should be used for directional control only during
the initial portion of the takeoff roll when the rudder and steerable nose wheel are ineffective. During the
initial takeoff roll it is advisable to monitor the engine instruments.
As the takeoff progresses, flight controls are used as necessary to compensate for wind conditions. Lift-off
should be made at, no less than Vmc + 5. After lift-off, the airplane should be allowed to accelerate to the allengine best rate-of-climb speed Vy, and then the climb maintained at this speed with takeoff power until a safe
maneuvering altitude is attained.
The landing gear may be raised as soon as practicable but not before reaching the point from which a safe
landing can no longer be made on the remaining portion of the runway. The flaps (if used) should be retracted
as directed in the airplane's operating manual.
Upon reaching safe maneuvering altitude, the airplane should be, allowed to accelerate to cruise climb speed
before power is reduced to normal climb power.
Short Field or Obstacle Clearance Takeoff
If it is necessary to take off over an obstacle or from a critically short field, the procedures should be altered
slightly. For example, the initial climb speed that should provide the best angle of climb for obstacle clearance
is Vx rather than Vy. However, Vx in some light twins is below Vmc. In this case, if the climb were made at
Vx and a sudden power failure occurred on one engine, the pilot would not be able to control the airplane
unless power were reduced on the operating engine. This would create an impossible situation because it
would not be likely that the airplane could clear an obstacle with one engine inoperative and the other at some
reduced power setting. In any case, if an engine fails and the climb is to be continued over an obstacle, Vxse
must be established if maximum performance is to be obtained.
Generally, the short field or obstacle clearance takeoff will be much the same as a normal takeoff using the
manufacturer's recommended flap settings, power settings, and speeds. However, if the published best angleof-climb speed (Vx) is less than Vmc + 5, then it is recommended that no less than Vmc + 5 be used.
During the takeoff roll as the airspeed reaches the best angle-of-climb speed, or Vmc + 5, whichever is higher,
the airplane should be rotated to establish an angle of attack that will cause the airplane to lift off and climb at
that specified speed. At an altitude of approximately 50 feet or after clearing the obstacle, the pitch attitude can
be lowered gradually to allow the airspeed to increase to the all engine best rate-of-climb speed. Upon
45
reaching safe maneuvering altitude, the airplane should be allowed to accelerate to normal or enroute climb
speed and the power controls reduced to the normal climb power settings.
Engine Failure on Takeoff
If an engine should fail during the takeoff roll before becoming airborne, it is advisable to close both throttles
immediately and bring the airplane to a stop. The same procedure is recommended if after becoming airborne
an engine should fail prior to having reached the single-engine best rate-of-climb speed (Vyse). An immediate
landing is usually inevitable because of the altitude loss required -to increase the speed to Vyse.
The pilot must have determined before takeoff what altitude, airspeed, and airplane configuration must exist to
permit the flight to continue in event of an engine failure — the pilot also should be ready to accept the fact
that if engine failure occurs before these required factors are established, both throttles must be closed and the
situation treated the same as engine failure on a single-engine airplane. If it his been predetermined that the
engine-out rate of climb under existing circumstances will be at least 50 feet per minute at 1,000 feet above the
airport, and that at least the engine-out best angle-of-climb speed has been attained, the pilot may decide to
continue the takeoff.
If the airspeed is below the engine-out best angle-of-climb speed (Vxse) and the landing gear has not been
retracted, the takeoff should be abandoned immediately.'
If the engine-out best angle-of-climb speed (Vxse) has been obtained and the landing gear is in the retract
cycle, the pilot should climb at the engine-out best angle-of-climb speed (Vxse) to clear any obstructions, and
thereafter stabilize the airspeed at the engine-out best rate-of-climb speed (Vyse) while retracting the landing
gear and flaps and resetting all appropriate systems.
When the decision is made to continue flight, the single-engine best rate-of-climb speed should be attained and
maintained (Fig. 16-13). Even if altitude cannot be maintained, it is best to continue to hold that speed because
it would result in the slowest rate of descent, and provide the most time for executing the emergency landing.
After the decision is made to continue flight and a positive rate of climb is attained, the landing gear should be
retracted as soon as practical.
If the airplane is just barely able to maintain altitude and airspeed, a turn requiring a bank greater than
approximately 15 degrees should not be attempted. When such a turn is made under these conditions, both lift,
and airspeed will decrease. Consequently, it is advisable to continue straight, ahead whenever possible, until
reaching a safe maneuvering altitude. At that time a steeper bank may be made safely-and in either direction.
There is nothing wrong with banking toward a "dead" engine if a safe speed and zero sideslip are maintained.
When an engine fails after becoming airborne, the pilot should bold heading with rudder and simultaneously
roll into a bank of at least 5 degrees toward the operating engine. In this attitude the airplane will tend to turn
toward the operating engine, but at the same time, the asymmetrical power resulting from the engine failure
will tend to turn the airplane toward the "dead" engine. The result is a partial balance of those tendencies and
provides for an increase in airplane performance as well as easier directional control.
NOTE — In this situation the ball in the turn-and-bank indicator will be approximately one ball width off
center toward the good engine.
The best way to identify the inoperative engine is to note the direction of yaw and the rudder pressure required
to maintain heading. To counteract the asymmetrical thrust, extra rudder pressure will have to be exerted on
the operating engine side. To aid in identifying the failed engine, some pilots use the expressions "Best Foot
Forward," or "Dead Foot Dead Engine." Never rely on tachometer or manifold pressure readings to determine
which engine has failed. After power has been lost on an engine, the tachometer will often indicate the correct
r.p.m. and the manifold pressure gauge will indicate the approximate atmospheric pressure or above.
46
Experience has shown that the biggest problem is not in identifying the inoperative engine, but rather in the
pilot's actions after the inoperative engine has been identified. In other words, a pilot may identify the "dead"
engine and then attempt to shut down the wrong one — resulting in no power at all. To avoid this mistake, the
pilot should verify that the dead engine has been identified by retarding the throttle of the suspected engine
before shutting it down.
When demonstrating or practicing procedures for engine failure on takeoff, the feathering of the propeller and
securing of the engine should be simulated rather than actually performed, so that the engine may be available
for immediate use if needed; but all other settings should be made just as in an actual power failure.
In all cases, the airplane manufacturer's recommended procedure for single-engine operation should be
followed. The general procedure listed below is not intended to replace or conflict with any procedure
established by the manufacturer of any airplane. It can be used effectively for general training purposes and to
emphasize the importance of Vyse. It should be noted that this procedure is concerned with an engine failure
on a takeoff where obstacle clearance is not critical. If the decision is made to continue flight after an engine
failure during the takeoff climb, the pilot should maintain directional control at all times and:
1. Maintain Vyse.
2. Check that all mixture controls, prop controls, and throttles (in that order) are at maximum permissible
power settings.
3. Maintain Vyse.
4. Check that the flaps and landing gear have been retracted.
5. Maintain Vyse.
6. Decide which engine is inoperative (dead).
7. Maintain Vyse.
8. Raise the wing on the suspected "dead" engine side at least 5 degrees.
9. Maintain Vyse.
10. Verify the "dead" engine by retarding the throttle of the suspected engine. (If there is no change in
rudder form, then that is the inoperative engine.)
11. Maintain Vyse.
12. Feather the prop on the "dead" engine (verified by the retarded throttle).
13. Maintain Vyse.
14. Declare an emergency if operating from a tower controlled airport. Advise the tower of your
intentions.
15. Maintain Vyse.
Engine Failure Enroute
Normally, when an engine failure occurs while enroute in cruising flight, the situation is not as critical as when
an engine fails on takeoff. With the more leisurely circumstances, the pilot should take time to determine the
cause of the failure and to correct the condition, if possible. If the condition cannot be corrected, the singleengine procedure recommended by the manufacturer should be accomplished and a landing made as soon as
practical.
A primary error during engine failure is the pilot's tendency to perform the engine-out identification and
shutdown too quickly, resulting in improper identification or incorrect shutdown procedures. The element of
surprise generally associated with actual engine failure may result in confused and hasty reactions.
When an engine fails during cruising flight, the pilot's main problem is to maintain sufficient altitude to be
able to continue flight to the point of intended landing. This is dependent on the density altitude, gross weight
of the airplane, and elevation of the terrain and obstructions. When the airplane is above its single-engine
service ceiling, altitude will be lost. The single-engine service ceiling is the maximum density altitude at which
the single-engine best rate-of-climb speed will produce 50 FPM rate of climb. This ceiling is determined by
47
the manufacturer on the basis of the airplane's maximum gross weight, flaps and landing gear retracted, the
critical engine inoperative, and the propeller feathered.
Although engine failure while enroute in normal cruise conditions may not be critical, it is a recommended
practice to add maximum permissible power to the operating engine before securing or shutting down the
failed engine. If it is determined later that maximum permissible power on the operating engine is not needed
to maintain altitude. it is a simple matter to reduce the power. Conversely, if maximum permissible power is
not applied, the airspeed may decrease much farther and more rapidly than expected. This condition could
present a serious performance problem, especially if the airspeed should drop below Vyse.
The altitude should be maintained if it is within the capability of the airplane. In an airplane not capable of
maintaining altitude with an engine inoperative under existing circumstances, the airspeed should be
maintained within ±5 knots of the engine-out best rate-of-climb speed (Vyse) so as to conserve altitude as long
as possible to reach a suitable landing area.
After the landing gear and flaps are retracted and the failed engine is shut down and everything is under
control (including heading and altitude), it is recommended that the pilot communicate with the nearest ground
facility to let them know the flight is being conducted with one engine inoperative. FAA facilities are able to
give valuable assistance if needed, particularly when the flight is conducted under IFR or a landing is to be
made at a tower-controlled airport. Good judgment would dictate, of course, that a landing be made at the
nearest suitable airport as soon as practical rather than continuing flight.
During engine-out practice using zero thrust power settings, the engine may cool to temperatures considerably
below the normal operating range. This factor requires caution when advancing the power at the termination of
single-engine practice. If the power is advanced rapidly, the engine may not respond and an actual engine
failure may be encountered. This is particularly important when practicing engine-out approaches and
landings. A good procedure is to slowly advance the throttle to approximately one-half power, then allow it to
respond and stabilize before advancing to higher power settings. This procedure also results in less wear on the
engines of the training aircraft.
Restarts after feathering require, the same amount of care, primarily to avoid engine damage. Following the
restart. the engine power should be maintained at the idle setting or slightly above until the engine is
sufficiently warm and is receiving adequate lubrication.
Although each make and model of airplane must be operated in accordance with the manufacturer's
instructions, the following typical checklist is presented to familiarize the transitioning pilot with the actions
that may be required when an engine fails.
ENGINE FAILURE DURING FLIGHT
1. Mixtures — AS REQUIRED for flight altitude.
2. Propellers — FULL FORWARD.
3. Throttles — FULL FORWARD.
4. Landing Gear — RETRACTED.
5. Wing Flaps — RETRACTED.
6. Inoperative Engine — DETERMINE. Idle engine same side as idle foot.
7. Establish at least 5 degrees Bank — TOWARD OPERATIVE ENGINE.
8. Inoperative Engine — SECURE.
a. Throttle — CLOSE.
b. Mixture — IDLE CUT-OFF.
c. Propeller — FEATHER.
d. Fuel Selector — OFF.
e. Auxiliary Fuel Pump — OFF.
f. Magneto Switches — OFF.
48
g.
h.
9.
a.
b.
c.
d.
e.
10.
11.
12.
Alternator Switch — OFF.
Cowl Flap — CLOSE.
Operative Engine — ADJUST.
Power — AS REQUIRED.
Mixture — AS REQUIRED for flight altitude.
Fuel Selector — AS REQUIRED.
Auxiliary Fuel Pump — ON.
Cowl Flap — AS REQUIRED.
Trim Tabs — ADJUST bank toward operative engine.
Electrical Load — DECREASE to minimum required.
As Soon As Practical — LAND.
AIRSTART (After Shutdown)
Airplanes Without Propeller Unfeathering System:
1. Magneto Switches — ON.
2. Fuel Selector — MAIN TA.NK (Feel For Detent).
3. Throttle — FORWARD approximately one inch.
4. Mixture — AS REQUIRED for flight altitude.
5. Propeller — FORWARD of detent.
6. Starter Button — PRESS.
7. Primer Switch — ACTIVATE.
8. Starter and Primer Switch — RELEASE when engine fires.
9. Mixture — AS REQUIRED.
10. Power — INCREASE after cylinder head temperature reaches 200 degrees F.
11. Cowl Flap — AS REQUIRED.
12. Alternator — ON.
Airplanes With Propeller Unfeathering System:
1. Magneto Switches — ON.
2. Fuel Selector — MAIN TANK (Feel For Detent).
3. Throttle — FORWARD approximately one inch.
4. Mixture — AS REQUIRED for flight altitude.
5. Propeller — FULL FORWARD.
6. Propeller — RETARD to detent when propeller reaches 1000 RPM.
7. Mixture — AS REQUIRED.
8. Power — INCREASE after cylinder head temperature reaches 200 degrees F.
9. Cowl Flap — AS REQUIRED.
10. Alternator — ON.
Engine-Out Approach and Landing
Essentially, an engine-out approach and landing is the same as a normal approach and landing. Long, flat
approaches with high power output on the operating engine and/or excessive threshold speed that results in
floating and unnecessary runway use should be avoided. Due to variations in the performance, limitations, etc.,
of many light twins, no specific flightpath or procedure can be proposed that would be adequate in all engineout approaches. In most light twins, however, a single-engine approach can be accomplished with the
flightpath and procedures almost identical to a normal approach and landing (Fig. 16-14). The light-twin
manufacturers include a recommended single-engine landing procedure in the airplane's operating manual.
During the checkout, the transitioning pilot should perform approaches and landings with the power of one
engine set to simulate the drag of a feathered propeller (zero thrust), or if feathering propellers are not
installed, the throttle of the simulated failed engine set to idling. With the "dead" engine feathered or set to
49
"zero thrust," normal drag is considerably reduced, resulting in a longer landing roll. Allowances should be
made accordingly for the final approach and landing.
The final approach speed should not be less than Vyse until the landing is assured; thereafter, it should be at
the speed commensurate with 'the flap position until beginning the roundout for landing. Under normal
conditions the approach should be made with full flaps; however, neither full flaps nor the landing gear should
be extended until the landing is assured. With full flaps the approach speed should be 1.3 Vso or as
recommended by the manufacturer.
The pilot should be particularly judicious in lowering the flaps. Once they have been extended it may not be
possible to retract them in time to initiate a go-around. Most of the light twins are not capable of making a
single-engine go-around with full flaps.
50
Flying A Multi-Engine Airplane
Thinking of going for your multiengine rating? Flying a twin isn't really that tough when everything is
working. But when an engine quits, watch out! Here's an overview of what to expect from a veteran flight
instructor. Sometime, watching a twin-engine aircraft taxi out and take off, you've probably wondered if you
could fly one. When you poke your head inside the cockpit, it does look kinda complicated. Lots of knobs and
dials there.
But to let you in on a little secret: it's really not that tough -- most of the time. When everything is
working, you just grab two throttles instead of one, and away you go.
The systems can be a little more complex -- the fuel plumbing is a bit bizarre in some types, there's
likely a gas-powered cabin heater in the nose [a la VW bug], the props are constant speed, and the gear
retracts.
But when everything is working, it's not really a lot different than flying a retractable single such as a
Bonanza, Mooney, Comanche, or Arrow. In fact, if you're considering getting your multi endorsement, one
idea is to first get checked out in one of these retractable-gear singles.
The transition from a simple, fixed-gear, fixed-pitch-prop single to a twin is probably busier than it
needs to be. Make life easier on yourself. If you can, learn about constant speed props, cowl flaps, retractable
landing gear and other fancy frills in a cheaper single-engine aircraft before you start shelling out the big bucks
renting a multi.
Why A Multi-Engine Aircraft?
Have you ever wondered why a manufacturer puts more engines on an airframe? There are many
people who think that it's for safety; that a twin is safer than a single. After all, if one engine fails, well, you
just keep on flying on the remaining one, right? No. When one engine on a twin fails, you don't lose half of
your excess thrust, you typically lose 80% of your excess thrust, which means that if you were climbing at
1200 fpm with both engines, if you configure and fly the aircraft perfectly after an engine failure, you will
likely see around 200 fpm, which is pretty bad.
Most light twins, when operated anywhere near gross weight, have very marginal single-engine
performance, and are very intolerant of pilot error in achieving a positive rate of climb. A non-turbocharged
twin will typically have a single-engine service ceiling of around 5000 foot density altitude. So, an engine
failure in cruise in summer means you're likely going to descend.
Remember, with two engines, you're twice as likely to have an engine failure. So why on earth would
a manufacturer install two engines instead of one? Apart from specifically-built multi time-builders and
trainers, the answer is: for more power. If a manufacturer can't get 500 hp from one engine for a 5000 lb.
aircraft, well, the answer is to put 250 hp on each side. However, there is additional drag created by the drag
of the engine nacelle on each side.
51
There is another problem with putting two engines out in
the wings. When both engines are pulling, everything is nice and
symmetrical. But when one engine fails, it is no longer providing
thrust -- the other engine is providing all the thrust, and in doing
so, it causes the aircraft to yaw towards the failed, or dead engine.
It's actually worse than that. The dead engine, in addition
to no longer providing thrust, is also creating drag, since the
propeller is windmilling, and the energy to spin the prop has to
come from somewhere. The drag the windmilling prop creates
also causes the aircraft to yaw towards the dead engine.
Instinctively, the pilot will try to stop the yaw by stomping on the
rudder pedal on the side of the engine which is still producing
thrust. In fact, this is how a pilot identifies the dead engine; the
;dead; foot, which no longer needs to push on the rudder pedal, is
on the side of the ;dead engine.
At this point, the pilot ;feathers the dead engine. The prop control is pulled all the way back, beyond
the feather detent, and the prop blades rotate to maximum coarse pitch, which minimizes drag. In fact, at this
point, the propeller of the dead engine will stop rotating. It's really weird, flying along, looking at the stopped
blades of a feathered engine.
Back to opposing the yaw. We all know that as you slow down, flight controls get sloppy -- they lose
effectiveness. Below a certain speed, the rudder will not have enough authority to oppose the yawing into the
dead engine. This results in the aircraft rolling inverted into a spin, and nearly always the deaths of all the
occupants, which creates bad press for general aviation. What is usually recommended in this situation is to
reduce the power on the good engine, and to lower the nose to increase airspeed, in order to maintain control.
Neither of these is a particularly desirable choice at low altitude, right after takeoff. As a result, climbing at
slow speeds is strongly frowned upon in twins. So strongly, in fact, that this minimum yaw control speed,
known as Vmc, is painted as a red line on the airspeed indicator, in addition to Vne. Rotation on takeoff
before Vmc is really discouraged.
Vmc
As a matter of standardization, Vmc is determined at maximum gross weight, with the center of
gravity [C of G] at the maximum aft position, at sea level, with the flaps set to the takeoff position, the landing
gear retracted, with all engines developing maximum power at the time the critical engine fails and windmills,
with a maximum of 5 degrees of bank into the good engine.
Whew. And hold on just a cotton-pickin' minute, you say. What's all this rubbish about a critical
engine? And 5 degrees of bank?
Critical Engine
Let's talk about the critical engine. Look at a twin from behind. The two normal piston engines, that
the manufacturer purchased from Lycoming or continental, will rotate clockwise when viewed from behind,
just like in a single. And remember slow flight, from your private pilot training? Having to stand on the right
rudder, because the down going blade creates more [asymmetric] thrust? Well, exactly the same thing is at
work here. If the right engine fails, and we slow down, looking at a twin from behind, the down going blade
of the left engine will be inside the nacelle, closer to the fuselage. This results in a shorter arm for the thrust,
which means less torque, or yawing. But if the left engine fails, as we slow down, looking at the twin from
behind, the down going blade of the right engine is outside the nacelle, away from the fuselage, which means
more torquing or yawing, which means you need more rudder.
All this hand waving boils down to that, as far as control goes, it's worse when the left engine packs it
in. This is why the left engine is called the ;critical engine. To help this, in the late 1960's and early 1970's,
52
airframe manufacturers started installing a counter-clockwise rotating engine on the right side, so it wasn't as
tough to stay straight when the left engine packed it in. The down going blade on the right engine is now close
to the fuselage, just like on the left engine. This why a twin with counter-rotating propellers is said to not have
a critical engine -- from a control standpoint.
Banking Into The Good Engine
Now, what's this weird business about 5 degrees of bank into the good engine? Well, remember that
as we bank an aircraft, the lift produced by the wing banks or tilts, too. We can break up the tilted lift into two
parts, the vertical and the horizontal. After an engine fails, if we bank towards the good engine, the horizontal
component of the tilted lift opposes the yawing into the dead engine.
If a little is good, then more must be better, right? Well, if we increase our bank into the good engine,
sure, we increase the horizontal component of lift, and we don't need as much rudder. But there's no such
thing as a free lunch. As you bank the aircraft, the vertical component of lift decreases, and the aircraft starts
to descend. It's important to realize when flying multi-engine aircraft that control and performance are totally
separate issues, and in fact are usually at odds with one another. The 5 degrees of bank chosen for the Vmc
demonstration is entirely arbitrary, and has nothing to do with achieving maximum performance at the higher
single engine best rate of climb speed, known as Vyse, which is painted on the ASI as a blue line.
Excessive bank at Vyse, which is nice but not needed for control, really hurts climb performance,
which is usually already hurting. To achieve maximum [published flight manual] single-engine climb rate, a
rule of thumb is 2 degrees of bank with a non-critical engine failure, and 3 degrees of bank with a critical
engine failure. Past these bank angles, a sideslip into the good engine will result. And we all know how a
sideslip creates drag, which is sure not what we want during a single-engine climb. In fact, with enough bank
into the good engine, you can take your foot right off the good side rudder pedal, and may even need some
rudder on the side of the dead engine to stay straight.
Great control, but atrocious performance, with a big negative number guaranteed on the VSI. You
don't have to take my word on this, by the way. Tape a yaw string on the nose of your favorite twin, and see
for yourself how many degrees of bank you really need at Vyse with one engine out. Betcha you're slipping
into the good engine at 5 degrees of bank.
For more information about this, there's a video you can order on this subject for $28.00 (US):
Optimized Engine-Out Procedures for Multi-Engine Airplanes
Embry-Riddle Aeronautical University
University Distribution Center
Daytona Beach, FL 32014
(904) 239-6484
One fascinating example from the video: a Piper Seminole at 5.6 degrees angle of bank (could you fly
within 0.6 degrees angle of bank?!) had a ZERO climb rate on 1 engine. Best climb was a little better than 100
fpm at just over 2 degrees angle of bank. A small note here: to achieve maximum rate of climb at higher
density altitudes, remember that Vy decreases as altitude increases, or as weight decreases. Slight finessing of
your angle of bank and your airspeed after an engine failure could be the difference between a climb and a
descent.
Some more information on multi-engine flying is available from AOPA's Air Safety Foundation. The
first paper is titled: ;Principles to Bank On and is the cover story for the April 1989 issue of the ASF's Flight
Instructors' Safety Report (Vol. 15, #2). The second is: Engine-Out Booby Traps for Light Twin Pilots and is
the cover story for the April 1993 issue (Vol 19, #2).
Weight
53
So, we can see that the angle of bank into the good engine in addition to affecting performance, most
definitely affects Vmc. What else affects Vmc? Well, the published Vmc figure is determined at maximum
gross weight. Does weight affect Vmc? Sure it does. Why? Well, remember, at a heavier weight, if the
aircraft is level, the wings must be producing more lift than at a lighter weight. Think of the lift vector being
longer. And when we bank the aircraft into the good engine, the longer lift vector gives us a longer horizontal
component, which opposes yaw, helps the rudder, and reduces Vmc. At least, according to conventional
wisdom. But there's a catch. At a heavier weight, the wing is at a higher angle of attack to generate the
additional lift. And as the angle of attack increases, so does the asymmetric thrust from the down going blade
of the good engine, which is what we have to oppose with the rudder.
Altitude
What else can change Vmc? Well, remember that Vmc is determined at sea level. Does altitude affect
indicated Vmc? You betcha. Why? Well, since the good engine is putting out less power at the air higher
altitude, there is less torque for the rudder to have to overcome. At the same indicated airspeed, the flight
controls will of course have the same effectiveness. This little detail has caused heartburn for more than one
neophyte multi instructor, who in the interest of safety climbs to a what he thinks is a nice, safe high altitude
on a hot day for a Vmc demo.
However, since Vmc has decreased below the stall speed, what the new multi instructor ends up
demonstrating is a full power single-engine stall and spin. Oops. Curiously, the official Transport Canada
Instructor Guide: Multi-Engine Class Rating [TP11575E] doesn't mention this at all in the Vmc demo
guidelines, on page 32.
Center of Gravity
Does C of G affect Vmc? Sure does. Published Vmc is determined with the C of G at it's maximum
aft location. If the C of G is moved forward, Vmc decreases because the arm of the rudder gets longer, so it
can create more torque, to oppose the yawing.
As I said before, it's not too tough to fly a multi-engine aircraft -- most of the time. But when one
engine packs it in, especially right after takeoff, there is probably no room for any error. The pilot must do
everything perfectly, quickly.
54
Twins vs. Singles: The Great Debate
A practical look at an age-old argument By Peter A. Bedell (From AOPA Pilot, August 1998.)
Buying an airplane is much like buying a car. You know what you want and you know what you need. You
may want a Ferrari but need a minivan. Many times, however, buyers bite off more than they can chew when
they show up at the dealer to buy an economical hatchback and drive off in a gas-guzzling sport-utility vehicle
decked out with running boards and leather seats.
Pilots tend to be a little more practical -minded compared to the typical car buyer. It's not often that a buyer
flies off in a Beech Duke after kicking the tires of the used Piper Archer next to it-or would he? Several
questions need to be asked when considering the purchase of an airplane-after all, it is probably the secondmost-expensive purchase you'll ever make. One of those key questions has spawned one of the greatest debates
in aviation, bar none. Whether it comes up while shooting the breeze in the airport restaurant or when you're
face-to-face with an aircraft broker, that fateful question, "twin or single?" has to be answered.
Economics
The cost of ownership may make short work of the twin/single decision. Don't be fooled by low purchase
costs-buying a twin is the easy part. You can get an old Cessna 310 or Beech Baron for just a little more
money than that required for their single-engine stablemates of the same model year. It's the maintenance and
fuel burn of the twin that make ownership hairy. It's safe to assume that the twin will cost three times as much
as the comparable single in terms of fuel, maintenance, insurance, and engine reserves.
Availability of aftermarket modifications is another point worth considering when making the twin/single
decision. Recently, we greatly enhanced the usefulness of AOPA's Beech A36 Bonanza by installing tip tanks
under a supplemental type certificate held by Beryl D'Shannon. Not only do the tip tanks greatly increase the
Bonanza's range, they also allow for a 183-pound maximum gross weight increase regardless of whether the
tips are filled. The result is a far more versatile airplane that can fly as far as the twin-engine 58 Baron at 75percent power and even carry a few more pounds of payload. Like the twin, this particular A36 is quite well
equipped with a standby vacuum system, radar, Stormscope, and air conditioning. Add deicing boots or the
TKS deicing system and you'd have a serious all-weather airplane-as long as that one engine keeps running.
That one engine
Here, as well, is where the debate may quickly end. There are those who simply can't trust one engine and for
whom nothing less than two engines will do. A few years back much of the editorial staff was ogling over a
new PC-12 that Pilatus had brought to AOPA Pilot for evaluation. A veteran charter operator on the field
stopped by for a look at the gargantuan turbine single and asked the $64,000 question, "How much?"
$2.7 million," I said.
"All that money and you still only have one engine?" he replied.
"Yeah, but it's a PT-6," I said, leaning on knowledge that the Pratt & Whitney has an impressive reliability
rating. He looked at me as a grizzled old-timer looks at a teenage punk and related three incidents in which
turbine engines had failed on him in flight.
"I'd still put my money into a used [King Air] 200," he grumbled as he walked away.
Others draw the line on buying a twin when they consider the terrain over which they'll be flying. Those
regularly flying over miles of water or mountainous terrain are definitely going to give the twin an extra-hard
look. Operations in mountainous areas also bring attention to service ceiling. The twin's service ceiling is
generally far higher than a comparable single's, allowing better routing options for flight over high terrain
55
where minimum en route altitudes (MEAs) are beyond the altitude capabilities of a single. On the other side of
the coin is the fact that the pilot of a normally aspirated twin could be in just as much trouble as the pilot of a
single if an engine quits. Most normally aspirated twins' single-engine service ceilings are below that of
mountainous terrain in the West. Confidence in engine reliability may lead the twin pilot to file a route with
MEAs far above the single-engine service ceiling. Time to start thinking about turbocharging now. Heck,
while you're at it, tack on pressurization, too.
Need for speed
From somewhere back in your training you may recall a rule that says to double an airplane's airspeed, you
must quadruple the power. With that in mind, it's no surprise to find out that true twins (those outfitted with
double the power of their single-engine derivatives) don't outperform the comparable singles by any huge
margin. In some cases the single-engine variants outperform the twin, as is the situation with the Piper
Comanche 400 and Twin Comanche.
A perfect pair to pit in the twin/ single dual is the Baron and Bonanza. With double the power, the 58 Baron
musters a realistic 195-knot cruise speed at 75percent power. The single-engine Beech A36 Bonanza can
manage about 170 knots at the same power setting and is burning only half the fuel, or 16 gallons per hour. So
the Baron's extra 25 knots comes at a penalty of double the fuel burn and engine maintenance. Are those 25
knots worth it? That depends.
Twins outperform singles significantly in climb rate, which leads to reduced block-to-block times. Let's use a
400nm no-wind trip to and from sea-level airports as an example of the difference between the Bonanza and
Baron. After a gross-weight takeoff, the Baron, at its 136-knot cruise climb, requires 6.5 minutes, five gallons
of fuel, and 15 nm to reach 7,000 feet. Meanwhile the Bonanza, at its 11 0-knot cruise climb, takes 9.5
minutes, burns 3.25 gallons of fuel, and covers 17.5 nm getting up to 7,000 feet. Average rate of climb to
7,000 feet for the Baron is 1,100 fpm, while the Bonanza ascends at 750 fpm.
After level-off, the Baron, with its excess power, rapidly reaches its cruise speed, while the Bonanza can take
several minutes to stabilize in cruise. After a 500-fpm descent, the Baron arrives in the traffic pattern at the
destination after a total of two hours and four minutes of flight. The Bonanza will follow 19 minutes later-not a
huge difference, but certainly noticeable. The Bonanza's slower climb rate is pronounced when comparing the
block-to-block times with the twin.
When you taxi to the pumps, though, the Bonanza fights back. The Baron will have used 43 percent more fuel66.5 gallons versus 38.5 gallons. At $2.25 per gallon, that's a difference of $63. As you can see, if you don't
fill the seats in the twin, you may as well throw money into the fuel cells.
The safety question
The safety aspect of the great twin/single debate has been beaten to death in various articles over the years but
needs to be addressed. A 1979 National Transportation Safety Board study showed that pilots of twins are
lousy at maintaining control of the airplane after an engine has failed, especially just after takeoff. Most of the
accidents were loss-of-control (Vmc) spins, making the twin statistically more dangerous to fly than a single
when it came to the number of fatal accidents. In overall accidents the single was worse than the twin because
of that category's higher rate of forced landings. But most engine-failure accidents in singles resulted in
survivable forced landings.
In a single, the engine-out after-takeoff procedure is far simpler and consists of flying the airplane and running
through the checklist to be sure that the failure wasn't pilot-induced. After that it's simply a matter of finding a
good place to set the airplane down and resisting the temptation to pull back on the yoke. The flurry of
decisions required of the twin pilot is quite daunting and demands a high level of proficiency for the outcome
to be successful. Is there enough runway to land straight ahead? Is the density altitude too high to establish a
56
suitable climb? Are the gear and flaps up? The twin pilot has to carefully contemplate each takeoff in order to
make the correct decision in a timely manner.
The fatal accident problem in twins stems from a number of sources. Some pilots continue to fly the airplane
like a twin even though it loses 80 percent or more of its climb capability (see "Single-Engine Savvy," March
1997 Pilot), Others get confused in the cockpit and hurriedly make a wrong move, such as feathering the
propeller on the good engine or simply forgetting to fly the airplane.
In a nutshell, the twin is safer than the single if the pilot is proficient in single-engine operations and the
airplane is within weight and balance. Getting proficient on one engine in a twin is best done in a simulator
that mirrors the type twin you'll be flying. Simulator and recurrent training will do worlds of good in such a
situation, but be prepared to factor the four-figure-per-year cost into the price of that twin you are lusting after.
Double trouble?
Two engines and redundant systems are great for in-flight reassurance, but the glass-is-half-empty crowd
would argue that there is twice the opportunity for something to go wrong. Two vacuum pumps double the
chance that one will quit and strand you somewhere. While you're at it, you can double the opportunity for a
spark plug to get fouled or an injector to get clogged, etc. At overhaul it's time to really pay for that second
engine. Not only is there an extra engine; there are all of the associated accessories-vacuum pumps, prop
governors, hoses, engine mounts, and baffling, to name a few. Oh, and don't forget to overhaul those
propellers.
It is mostly the twin owners who make the argument that a twin's engines will last longer since they don't have
to work as hard. For example, since they climb so well, twins spend less time in high-power flight
configurations. Still others make the argument that the twin can operate at lower power settings and still
maintain speeds better than that of the comparable single at 75-percent power or better. We haven't seen any
concrete evidence that babying an engine will make it last longer, but the argument does make some sense.
Justification
If you consistently need to carry a big load out of short strips, then the twin is the better way to go. Will you
consistently fill four or more seats and the baggage compartment? Do you need to take those people on trips
longer than 600 nautical miles? If "yes" is the answer, then run the numbers on purchasing that twin.
Also consider the comfort of having extra baggage compartments. Nose and nacelle baggage compartments
can handle golf clubs and skis, freeing up space in the cabin for humans. On such trips in a single, the useful
load may actually be there, but seats could be unavailable because of the cargo's sheer bulk. Clever packing
may work, but passengers are hardly at ease when a ski pole or golf club runs amok in the cabin during
turbulence.
Fuel capacities are another point worth considering. Twins generally store more fuel and can stay aloft longer
while still making respectable true airspeeds. They have the excess power to carry all of that fuel to altitude
and, if power is restrained, each engine can sip that fuel at very low rates, providing nautical-mile-per-gallon
figures close to that of a comparable single at normal cruise. For example, a Twin Comanche with all of the
fuel tanks available by supplemental type certificates could stay aloft for an entire workday when the power is
reduced-and still cover the ground at 145 to 150 knots.
In addition, the twin makes those westbound trips a little easier to handle, given that its excess power has more
effect against those prevailing westerlies.
Is the debate over?
The merits of both airplane types can be argued indefinitely. The single's efficiency is so practical to some yet
the twin's brawny performance and machismo may be irresistible to others. Careful analysis of the specifics of
57
each type airplane will help you to make a more informed decision. After all, you don't want to botch the
second largest purchase you'll ever make.
58
Challenges: Multimanager
Learning to fly with half of a twin By Mark R. Twombly (From AOPA Pilot, December 1989.)
The flight was barely 30 minutes old, and already it was excruciatingly dear it would be a challenging day. On
three separate occasions, one or the other of the Aztec's two engines had suffered a temporary instructorinduced loss of power. First, the left engine went south on initial climb-out, followed by the right engine in the
middle of a holding pattern turn, and then, for good measure, the left one again on the way down to minimum
descent altitude during a VOR approach under the hood. The sweating student in the left seat was a blur of
elbows and hands flitting between engine power levers, fuel pump switches, and gear and flap handles. The
masochist in the right seat was beaming as if to say, "Welcome to multiengine training."
An instrument rating is the logical end point for a private pilot seeking to exploit the full personal
transportation potential of a single-engine airplane. But if the need is for more performance, utility, and
redundancy than a single can provide, a multiengine rating is in order.
Two engines can mean a better power-to-weight ratio and, therefore, better climb, cruise, and payload
performance. More important, two engines make for built-in systems redundancy and much better odds of
completing a safe on-airport landing m the event of an engine failure.
Deicing and weather avoidance equipment are approved and available on a few singles but are much more
common on multiengine airplanes. And if the move is into a medium to heavy twin, the passengers get to ride
in a large and comfortable cabin.
Used twins can be bought at bargain prices these days, but beware the hidden costs: not one but two engines
and twice the accessories to maintain and overhaul. Also, a new multiengine pilot likely will find insurance
expensive and restrictive. Initial and recurrent training in a factory school or approved independent program
may be required.
In the ratings acquisition sequence, the multiengine ticket usually follows the instrument rating. The contrasts
between the two are interesting. Instrument training typically is long, arduous, and thick with learning new
rules, regulations, and procedures governing every aspect of flying on the gauges.
Multiengine training is no picnic, but it is short in comparison-about 10 hours of instruction, on average. More
emphasis is placed on preflight performance planning, such as calculating the minimum runway length needed
to accelerate to rotation speed, lose an engine, and brake to a stop.
The multiengine student learns to rely on basic senses—listening for a sour note in the sound of the engines
and feeling for a change in attitude that would indicate a loss in power in one engine. Once sensed, the
emergency demands an immediate response. Bank into the good engine a maximum of five degrees, apply
rudder to overcome the yaw from the good engine, and keep the airspeed at or above best single-engine climb
speed.
At the same time, the power needs must be quickly assessed. How much power depends on the situation. If an
engine fails in cruise flight, a slight amount of additional power to the good engine may be in order. If it
occurs on takeoff, maximum power is essential. Push the power levers forward, turn the auxiliary fuel pumps
on, check flaps and gear up and fuel selectors properly positioned, and if time and circumstances permit,
troubleshoot the problem.
If it can't be fixed, feather the windmilling propeller to get rid of the tremendous drag it creates. Now is when
the three most familiar words known to multiengine pilots are invoked: "identify (idle foot, idle engine), verify
59
(reduce power on the suspect engine), feather (mixture to idle cutoff, propeller control to feather position,
throttle dosed, secure the engine)."
Multiengine training is incorrectly named. A more accurate description would be single-engine training in a
multiengine airplane, for that is the crux of the instruction. The mechanics of actually flying a twin are not
difficult to master. It's when a twin becomes a single that the going can get tough.
It is not known how often engines fail on twins and, by extension, what percentage of engine failures end in
loss-of-control accidents. An engine failure is always an emergency, but the most critical times are on takeoff
and approach to landing. Speed is slow, and with gear and flaps hanging, drag is at its highest.
Takeoff and landing also are the busiest times. The sudden demands of coping with an engine failure can be
overwhelming if the mind is not prepared.
A study by Robert E. Breffing Associates, Incorporated, of accidents that occurred from 1983 through 1987
concluded that engine failure or malfunction was involved in about eight percent of all fatal accidents in
single-engine, piston-powered airplanes. The figure for piston-powered multiengine airplanes was 25
percent—three times that of singles. Multiengine training must focus on single-engine flying.
What may be missing from multiengine instruction is more emphasis on the basics, such as fuel management
and instrument proficiency, because rated pilots are not meeting the challenge of flying multiengine airplanes
safely in those areas either.
A study performed by the AOPA Air Safety Foundation/Emil Buehler Center for Aviation Safety of 1,768
accidents that occurred from 1982 through 1987 involving piston and turboprop-powered twins revealed that
44 accidents, or 3.6 percent of all accidents attributed to pilot error (pilot error accounted for about 69 percent
of all the accidents), involved a loss of control following an engine failure.
That is the same number that occurred as a result of descending below approach minimums. Another 35
accidents were attributed to improper EFR approach and missed approach procedures. In fact, nearly 19
percent of multiengine accidents blamed on pilot error were weather-related.
Another 158 accidents, or 13 percent of pilot-error accidents, involved fuel problems, including running out of
gas completely or mismanaging the fuel system. Many twins have fairly complex fuel systems involving main
and auxiliary tanks with a series of pumps and interconnecting lines to transfer fuel from one tank to another.
Auxiliary fuel allows for a lot of flexibility in trading payload for endurance. Crossfeed capability enables the
pilot to tap all of the tanks even with one engine and fuel pump inoperative. However, the frequency of
accidents involving either fuel starvation or fuel exhaustion indicates that pilots either do not understand their
fuel systems or ignore the consequences of laissez-faire fuel management.
The training begins easily enough, with a couple of instrument approaches to evaluate the state of my
proficiency and some air work to establish a rapport with the airplane.
The 1978 Piper Aztec F, the last-model Aztec built, is an excellent multiengine instructional tool. It has the
stability, feel, and docile handling of a much larger airplane, and as a bonus, it is very easy to land well. The
Aztec also has at least a modicum of single-engine climb capability. The normally aspirated, 250-horsepower
Lycoming IO-540 engines are sturdy and dependable. What the Aztec lacks in speed, it makes, up for in
civility.
At the same time, there is a systems quirk that makes it a taskmaster in single-engine situations. If the left
engine fails, the lone engine-driven hydraulic pump isn't able to pressurize the fluid that makes the gear and
60
flaps go up and down. A second pump on the right engine was available as an option, but this particular Aztec
does not have it.
Consequently, prior to takeoff, the manual pump handle at the base of the power control pedestal has to be
extended, just in case. If the left engine fails after takeoff and you are committed to flying, it is imperative to
grab that handle and pump on it about 50 strokes to raise the gear. Otherwise, there is no hope of climbing out.
A single-engine go-around with gear and flaps extended is a pipe dream, the instructor, George Suranyi,
explains. Therefore, on an approach, be ready to attack that handle-but not until the landing is assured. One
begins to imagine worst-case scenarios: The left engine fails shortly after taking off into IMC or on a low
approach to a short runway.
We practice those scenarios-in make-believe conditions, of course—along with many others. Suranyi is
attempting to drill habitual response behavior into my protesting brain by routinely failing engines. Gradually,
I learn to split my thinking into three channels: one to consciously monitor my feet (in anticipation of the
exaggerated yaw that signals asymmetric power), one to direct my hands on their appointed rounds in the
event of an engine failure, and a third to maintain a vigil over flight and engine instruments and the world
outside the windshield.
Suranyi pronounces me ready for the inquisition, which is scheduled for the following morning, The next day I
wake up thinking in three-part harmony-a good sign. The oral test and check ride go well, according to Velta
Berm, the examiner, and I depart the FBO with a broad smile and a temporary certificate bearing her
handwritten endorsement, "Airplane-Single and Multiengine Land" tucked in my wallet.
What have I learned? That multiengine flying is the same as all flying. To do it successfully requires instinct,
habit, and aggressive thinking. The initial challenge is to build a proper foundation of those three ingredients
during training. The continuing challenge is to protect that foundation with practice and proficiency training.
61
Are 'Singles' Safer Than 'Twins'?
By W. E. Sprague (From AOPA Pilot, October 1973.)
Some few years after the Brothers Wright did their notable thing at Kitty Hawk, somebody took a notion to
hang an extra engine on an airplane-the idea being, presumably, that, among other supposed advantages, if one
engine should quit, the other would see you safely to the nearest airport or facsimile thereof.
History may be a bit vague as to just who deserves credit for this notion, but time has done the idea itself
proud. It finds more support today than its originator probably ever dreamed of. Insurance companies, for
example, will ask a lot less premium money if your airplane sports two fans. Some FBOs will refuse to rent
you anything but a "twin" if your aim is to fly IFR, or in the dark, or over any sizable stretch of mountains or
water. And even the FAA seems to endorse the idea, since, under FAR Part 135, it holds a much tighter rein on
air-taxi IFR-ing in "singles."
There can be no question that having an extra engine on a plane is a factor clearly favoring safety, at least in
principle. Yet much of what is said about twin-engine safety today is little more than old wives' tales and
wishful thinking.
Somehow, the twin's potential for staying aloft on only one engine has been translated over the years into the
idea that the all-around safety of any light plane is directly related to the number of engines it has. Certainly, a
large segment of the general public believes this, and, disturbingly enough, so do a lot of high-time pilots.
Unfortunately, it simply isn't true.
According to a recently released study by the National Transportation Safety Board (NTSB), twins crashed
only about half as frequently as singles. The study, which concerned itself with some 22,355 non-airline
accidents over the period 1965 through 1969, disclosed that, for every 100,000 hours flown in a single, there
were 4.6 accidents resulting from engine failure, while the rate for twins was only 2.3 per 100,000 hours. All
well and good—except that 22.9 percent of twin accidents were fatal, while only 5.4 percent of single
accidents ended in fatalities. Or, if you will, the single-engine aircraft was more than four times as safe when it
came to preserving the whole skins of its occupants.
Working from three other sources -FAA's 1969 Statistical Handbook of Aviation and Census of U.S. Civil
Aviation and NTSB's 1969 Annual Review of Aircraft Accident Data, U.S. General Aviation-one finds some
equally interesting data.
In this case, our focus is on accidents to singles and twins occurring in a single year, 1969. No so-called
ground incidents are included, and no emergency landings from which both planes and occupants emerged
unscathed.
Since our concern is strictly with the relative virtues of singles and twins, the figures derived from these
sources do not (as did the NTSB study cited above) include accidents that resulted from pilot error—only
those that resulted from "losing an engine" as a consequence of failure of the engine itself or one of its
components. Multi-engine training accidents are also excluded; while they may sometimes result from actual
loss of an engine, too often it is impossible to pinpoint the cause. The airplanes involved in these calculations
are restricted to modern planes used for fairly conventional purposes-i.e., no "dusters," no weather or other
research planes, no "experimental" birds.
In this frame of reference, where total accidents in 1969 are concerned -those that damaged only planes, plus
those that damaged both planes and their occupants-the twin comes out well, paralleling the accident-rate
picture shown by the five-year NTSB study. Specifically, the figures derived from our three sources show one
accident in twins, resulting from a lost engine, every 146,000 flying hours-as compared with one in singles
every 105,000 hours.
62
But when only serious accidents are counted—those in which people as well as planes were crunched—the
picture reverses somewhat dramatically. In twins, we find one such bad one, following a lost engine, every
443,800 hours; in singles, only one every 1,011,250 hours. In other words, your chances of being hurt or being
put away for good seem to be about 2.27 times greater in twins.
Both these calculations and those derived from NTSB's five-year study are based on dated figures, and the
situation may have changed for the better since 1969. However, preliminary studies for 1970 and 1971,
according to NTSB, show an average decrease in all accidents, from all causes, of only 177. It seems unlikely,
then, that the twins-versus-singles picture has changed significantly, even now.
The most curious thing in the statistical picture at hand—whether that picture is derived from the three sources
just cited or from the earlier mentioned five-year study—is that singles get crumpled anywhere from 40
percent to 100 percent more often than twins, yet do far less damage to their pilots and passengers. The fiveyear study, taking pilot error in relation to engine and fuel management into account, comes up with the higher
percentage. But even when this type of pilot error is eliminated from our calculations—even when the cause of
a crash is engine failure, pure and simple (which the five-year study found to be the case in over 44 percent of
the accidents examined)—there remains a striking implication that somehow singles are safer when and where
it really counts.
The long-accepted idea of twin-engine safety stands in contradiction to that implication and, at the very least,
seems to demand some sort of explanation.
The first possibility that comes to mind is that perhaps twins, on the average, carry more people per flight;
thus, while they "go in" less often than singles, more people are exposed to death and injury when they are
involved in an accident. If so, then the statistics might be giving a false picture, and twins would still be safer
on a per-passenger-mile basis.
Well, while there are no reliable statistics on passenger-miles flown in general aviation, FAA estimates set the
number of people per flight, for both twins and singles, at two-and-a-fraction. It would seem, then, that on the
average not more than three people are involved when a plane, either single or twin, gets bent following an
engine failure.
What about the possibility that twins are all heavy, high-performing planes and hence get crumpled more
seriously in crash-landings than do lighter, slower singles?
While there is some merit in this idea, a good many singles are heavy high-performers, too. Some, in fact,
perhaps outweigh and outperform some twins. Yet even compared with other singles, they do a superior job of
preserving the whole skins of their occupants-based on certain of our same sources and calculations, in fact,
about 1.5 times better for singles over 200 hp than for those with less.
Still, if there is any substance to the statistical implication that singles are safer than twins when it comes to
preserving life and limb, singles must have virtues unpossessed by twins, and conversely twins must have
vices unknown to singles. And such, indeed, seems to be the case.
When a single loses an engine, it still has a lot going for it, even if it's a big single. Compare, for example, a
high-performance single with a light twin. While the single comes within 20 percent to 25 percent of the twin's
speed, range, ceiling and useful load, it has a slightly better glide-ratio (assuming "both out" for the twin. Thus,
if the single quits in flight, its pilot has a bit more time and reach to use in finding a suitable spot. (A smaller
single has, of course, a lot more time and reach, but let's stick to our comparison.) On the way down, the highperformance single can approach that spot at 95 mph IAS, compared with 108 mph for the light twin with one
still turning. The single driver, therefore, has more time to plan his approach. And if the spot turns out to be
63
rock-strewn, potholed, or plowed, the single will touch down almost 10 mph slower. Finally, if the spot is a
"tight squeak," the single can get in nearly 200 feet shorter.
There's much to be said, then, for the idea that singles, especially lighter singles, fare better physically in
forced landings. Still one could argue that the above comparison is a bit like matching apples and bananas, so
perhaps the real virtue of the single lies elsewhere than in the laws of aerodynamics-perhaps, say, in human
psychology.
Aware that he has only one set of jugs, the average single driver, even if he also flies twins, seems more
inclined toward caution, opting for higher altitudes at night and over mountains or water, circumnavigating
really bad terrain altogether, and generally acting as if his single fan might indeed quit at any moment.
Conversely, the average twin driver, even if he also flies singles, seems inclined to put his faith in his extra
engine. Hence, when it gets suddenly quiet in a single, its pilot is more likely to be prepared. The twin driver,
though-even with one engine still churning-can easily find himself on the way into a night-darkened
mountainside (thanks to having compromised on altitude), or in for a swim. or in a panic to find a suitable spot
("just in case") down among all those crags and boulders and trees. Even if he gets to an airport, he may be in
for a new experience, since nothing in the "regs" calls for training in landing with one engine actually dead and
its propeller feathered. And if both engines quit on him, he's really in a bind, for in all likelihood he has never
landed before with two out.
So much for the virtues, both aerodynamic and psychological, of singles. What about the vices of twins?
As reliable as they are, modern airplane engines still quit, as witness our statistics. The twin, having a "spare,"
remains airborne in most Instances-which may explain why twins get crumpled less often than singles, but
fails to explain why they seem to damage more people. It's fairly common knowledge, though, that most
accidents happen when aircraft are approaching or departing from airports, and that many of these mishaps are
caused by power loss.
If such fate befalls a single, the bird may get dented, but, thanks to its aforementioned virtues, its occupants
stand an excellent chance of walking away. If such fate befalls a twin, no doubt it most often completes its
landing satisfactorily-or, on departure, hobbles around the patch, or makes a one-eighty, and gets back in all
right. But when it doesn't ... ? Sudden adverse yaw, pitch and rollall the unsavory traits of a twin that's just
"lost one"-combine with low speed and low altitude to create a situation that too often ends with the plane
"going in" nose first, or topside under, with generally catastrophic results.
Approach-departure accidents, then, may account for much of the statistical disparity between twins and
singles when it comes to keeping people intact. Significantly, the NTSB's five-year study concludes, in this
respect, that upon engine failure pilots should concentrate on avoiding, among other things, "a stall spin, stall
spiral, [or] stall."
But regardless of when and where it happens, losing one of two engines still contributes to that disparity
because of yet another vice of the twin. Beyond the unsavory engine-out traits mentioned above, a twin
reduced to flying on one set of jugs is, in effect, actually flying on less than one. At a recent West Coast safety
seminar, an FAA spokesman pointed out that, at sea-level density-altitude, a twin losing one engine loses 50
percent of its power-and 78 percent of its performance, relative to rate of climb. And at a density-altitude of
5,000 feet, that loss of performance becomes 88.5 percent.
In short, the twin's "spare" engine is not a spare at all; rather it's a vital component of the aircraft's total power
system, the loss of which is in many ways more critical than simple engine failure in a single, owing to sharply
decreased overall performance. True, the twin can still stay aloft, but only by dint of skillful handling. Add to
this the potentially treacherous effects of sudden asymmetric thrust and the vices of the twin become all too
64
apparent—as does the probable reason for the statistical disparity between singles and twins in the matter of
deaths and injuries.
"The trouble with twins," an old cliché has it, "is that there's twice as much to go wrong." Actually, there is
twice as much, if not more, to cope with if things do indeed go wrong. Which is why twins demand more in
the way of training, pilot proficiency, "backup" devices, and anything else conducive to better behavior when
an engine quits. It's why, too, the pilot who takes his multi-engine training lightly, or later neglects periodic
reviews of engine-out procedures (especially "under the hood," if he flies multi-engine EFR)-and the buyer
who stints on having two alternators and two hydraulic pumps -are both asking for trouble. And, old wives'
tales and wishful thinking aside, it is also why there's a lot more to safety in flying than the question of how
many engines an airplane has.
65
Multi-Engine Airplane Survival
Most light twins will perform advertised—the others will do better—if they have good engines, but a lot
depends upon the pilot's understanding the power he has available and how to use it
By Edwin W. Lewis, Jr. (From AOPA Pilot, October 1970.)
Congratulations. You have just purchased a modern, efficient light-twin airplane. You are, if an average pilot,
approximately half as safe as you were in your previous single-engine flying machine.
There arc several reasons for you to be properly cautious, about your new airplane. Not that it is in itself
unreliable or unairworthy—far from it. The crux of the problem is you, however, and your reliability and
understanding of the key parameters of multi-engine operation. You must constantly realize, understand, and
be competent to cope with the limitations of the man as well as the machine. Failure to do this will assuredly
be hazardous and expensive.
Most problems light airplane pilots have after transitioning to twins stern from training or, more precisely,
from lack of it. The salesman or instructor—with some notable exceptions—usually is trying to get you
"checked out" or get you "rated," rather than give you the expensive precision practice and training really
required. Also, the aircraft salesman is naturally interested in selling you on the good points of the airplane,
rather than pointing up its less sterling qualities. It follows, then, that if you are at all unsure of the quality of
your rating training or checkout, you should seek the advice and help required from a competent, experienced
multiengine instructor. By multi-engine instructor, I refer to one who has much experience in multi-engine
training, not an instructor with a lot of single-engine time who happens to have a little-used multi-engine
rating.
Most light-twin aircraft will perform as advertised with good engines; the remainder will perform slightly
better. That is, they will maintain the specified rates of climb or altitudes with an engine out, assuming the
specified criteria are met. These include gross weight, density altitude, engine condition, accurate airspeed
control, and smooth, precise control manipulation. The most critical requirement remains so for all time:
airspeed.
Two quick definitions are in order at this time: those of Vyse and Vxse.
Vyse is "best-rate-of-climb airspeed, single-engine." It is also the airspeed at which the airplane is able to
maintain level flight with the least power and gain the most altitude per unit of time with an inoperative
engine.
Vxse is "best-angle-of-climb airspeed, single-engine." It is the airspeed at which the airplane will gain the
most altitude for forward distance traveled, again with an engine inoperative. This speed is only of interest for
obstruction clearance and is not a speed to be maintained longer than necessary.
The airplane will not climb as fast at Vxse, and it requires more power per foot of altitude gained than Vyse.
Therefore if you cannot maintain at least level flight at Vyse, you darn sure cannot at Vxse. Conversely, if you
can maintain at least level flight at Vxse you normally can reach and climb at Vyse. To summarize: should
conditions occur which preclude attaining Vyse, or if the airplane is still descending at Vyse, then you are only
able to control the direction of the ensuing crash, and it is imperative that you know it and plan for it.
I know of no twin-engine, normally aspirated, propeller-driven airplane which will maintain altitude above
3,000 feet m.s.l. with a windmilling, inoperative engine. While this statement assumes gross-weight conditions,
other problems, such as high density altitude, make it equally true for less-than-gross-weight operation.
66
Your reaction may be: "But that's a windmilling engine and my bird has full-feathering props…." So what?
Feathering on some twins requires significant electrical power which might not be available. Others require
engine oil pressure for feathering, and considerable initial rpm.. Do you know how yours works?
Should you lose oil pressure all may not be irretrievably lost, as the engine may seize. This is good! A stopped
flat-pitch prop has considerably less drag than one which is windmilling, so if you cannot feather one, try and
stop it. Assuming you cannot do either, you are in deep yogurt, and a descent is inevitable.
Let's talk momentarily about "minimum control speed," alias Vmc. It is a figure computed under the most
unfavorable conditions obtainable and only references directional control, not climb or descent performance.
The parameters used to derive it include retracted landing gear, full takeoff power on the non-critical engine,
takeoff flap setting, center of gravity at the aft limit, and the critical engine windmilling.
Any alteration of these criteria will lower Vmc.. If the airplane is under gross weight, or the gear or flaps are
extended, or the dead engine is feathered, or the good engine is not strong, or the dead engine is not the critical
engine, Vmc will be lower than specified. Isn't that comforting? Well, no, it's not. If you cannot accelerate to at
least Vyse or Vxse and climb, you are still going to lose altitude, and hanging on at Vmc when all is inevitable
may allow the crash to occur off the airport instead of on it. We are only interested in Vmc for directional
control, and then only for directional control on the runway; we should be above Vmc prior to takeoff.
We get attached to Vmc during our airborne instruction. We learn the loss of directional control somewhere
near Vmc (on the low side) when practicing single-engine slow flight. Single-engine slow-flight practice may
well be akin to practicing bleeding. We kill more people in this practice than we do from actual engine
failures.
With the foregoing as preamble, let's discuss normal operations arid how to fly them. Following that will be a
few paragraphs on abnormal situations, or what to do until the airplane quits moving. Make a proper preflight,
both internal and external. This should include a proper functional check of all generators and hydraulic
pumps, as applicable. It should also include sampling fuel from all tanks.
If all tanks are full, start on the mains or tips, taxi on the auxiliary tanks, and run up on the mains. Alter this for
partial fuel loads as required; be sure you do the run-up on the tanks used for takeoff. After the run-up is
complete, verify trim settings, controls unlocked and free to all stops, fuel selectors on proper tanks and in
their detents, and the doors closed and locked.
Apply takeoff power smoothly and slowly. Five seconds from idle to takeoff power will lengthen the run
slightly, but ii is easier on the machinery. Use full takeoff power on every takeoff. While the engines may
accelerate satisfactorily with climb power, the engines may not be adequately cooled due to lack of power
enrichment operation.
After takeoff power is reached, lock all power controls with the palm of- your hand. Hold the airplane on the
runway until Vmc has been passed. The airplane may want to fly prior to Vmc; do not allow it. After Vmc, let
the airplane fly when ready, but remain in ground effect until reaching best-rate-of-climb speed (Vy). Climb at
Vy until reaching 500 feet above ground level (AGL). Do not retract the gear until there is no possible way
you could land on the remaining runway and overrun. After 500 feet AGL is passed, and the gear and flaps are
up, slowly make the reduction to climb power. Adjust cowl flaps and then, and only then, attain en route climb
speed. Clean up the after-takeoff check list and then you may enjoy the ride.
Now what have you done? Let's take each step in order:
1. You thoroughly checked electrical and hydraulic systems to verify continued systems operation as far
as possible after loss of an engine.
67
2. You precluded inadvertent power loss due to contaminated fuel or trying to fly on the "off" tank, in
which there is no fuel.
3. You insured against partial power loss due to creeping power controls until -safely airborne and at a
reasonable altitude.
4. You insured your ability to land on wheels instead of propellers in the event of power loss during and
immediately following takeoff.
5. You insured that the airplane gains the most altitude in relation to time before making the first—
historically most critical—power reduction.
6. You have covered—or tried to—as many problem areas as possible during takeoff, and have done it
with minimum possible wear on the equipment. Further, you have progressed through the takeoff in
the minimum practical time.
A minimum-run takeoff or other high-performance problem only changes those portions of the preceding
concerning initial run, liftoff, and initial climb. Set full power before brake release. Rotate and climb at Vx
instead of Vy. If your airplane has gear doors which are normally open on the ground, or no doors, retract the
gear when safely airborne. If the doors are normally closed except during gear transit, leave the gear down.
The gaping holes uncovered by the opening doors will cause considerably more drag than the down-andlocked gear itself. When clear of the limiting obstruction, allow the airspeed to increase to Vy, retract the gear
and continue as before.
A word or two on normal landings may be in order. Vmc is a nice-to-know number, but we are only concerned
with it on takeoff and in takeoff configuration. Vmc with landing configuration and approach power is below
"landing configuration stall speed," Vso. The landing should be based upon a final approach speed of 1.3 Vso
plus one-half the gust velocity. Therefore, if Vso for the present gross weight is 70 knots and the wind is down
the runway at 10 knots, with gusts to 20 knots, the proper final approach airspeed would be: 1.3 Vso = 91
knots plus one-half of 10 knots, or 96 knots. A minimum-run situation might require 1.15 Vso and all the gust
factor. In the above example, the minimum-run landing final approach speed would be: 1.15 Vso = 80 knots,
plus 10 knots, or 90 knots.
As the landing is assured—over the fence—allow the airspeed to dissipate commensurate with runway length.
Should you have to make a multi-engine go-around, apply takeoff power if required, and bring the flaps up to
takeoff position. After the airplane is up and climbing, raise the gear and continue as in a normal takeoff.
Now we start with the problems. If you lose an engine prior to liftoff, abort! All throttles idle, and get on the
brakes, hard. Brakes and tires are cheaper than nose struts and props, so get it stopped on the runway. Engine
failure after liftoff requires the same action if sufficient runway remains.
The next is the bad one. You lose an engine after becoming airborne; you're out of runway, and you cannot
attain at least Vxse for some reason. Make your decision where you want it to crash and keep flying it until it
gets there and does, because it's going to.
Now the easy one. You lose an engine around 600 feet a.g.l., while retarding the engines to climb power. First
and foremost: identify the good engine. You have no control over the dead one, so make sure you know which
is the good one. It is the one on the same side as your foot which is doing the work. It has the higher cylinderhead temperature of the two, and it is not decreasing. Do not rely on manifold pressure, r.p.m., or fuel flow as
indicators, as they may tend to remain the same as the other engine.
With the good engine identified, the other one must be the dead one. Grasp its throttle and bring it to idle. If
nothing changes, you have indeed the dead engine's throttle. Grab its propeller control and feather the
windmilling prop. Move the feathering control rapidly and positively into the feathering detent. If you have
properly balanced the drag of the windmilling prop, the nose of the airplane will now yaw towards the good
68
engine. This is an adequate indication of feathering for the moment, especially at night when you are a bit busy
to look.
Maintain Vyse or use Vxse if required. If everything works as advertised, the airplane will climb. Climb this
way until a thousand feet or so above the airport and cautiously retard the good engine to "maximum except
takeoff" (METO , or to climb power if these lower settings will allow you to maintain altitude and accelerate
above Vyse.
If you are going to return to the departure airport and land, you are in good shape. Turn downwind and fly the
exact same pattern you always do. This is no time to become a test pilot and start experimenting with a new
pattern whose key points are not visually familiar.
If you have sufficient power reserve, extend the gear on downwind So you will have time to get it down
manually if necessary. If no margin of power exists, leave the gear up until starting the descent on base leg.
Lower the flaps to the takeoff position—or to half, if no takeoff position is specified for your machine—early
on the base leg and stabilize the airspeed.
On final, set full flaps when landing is assured, and maintain precise, normal airspeed for a normal landing.
This is important, as the airplane will float farther with a feathered propeller than with two engines in idle.
Do not get suckered into a go-around with an inoperative engine unless you can start it at least 500 feet a.g.l.
If an airplane, car, or cow blocks the runway, land beside it, over it, on the taxiway, or on the grass, but do not
go around after you are committed on final approach. Your chances of losing control on a balked 1anding
approach with an engine out are excellent. I would much rather land long and take out the gear and.props than
foul up a single-engine go-around and take out the entire airplane.
If. you lose an engine and. are not going back to the departure airport, or if you are, but it will require a long
instrument operation, you should clear up the details when time, altitude, and navigation chores permit.
First, climb to the altitude you require at Vyse. After level-off, you may be able to maintain Vyse or higher at
75% power on the good engine. If not, take the power required, as you can always change that engine too. Do
not forget to monitor fuel consumption, as it will be high. Cross-feed as required; be sure of desired fuel-panel
setup prior to switching tanks.
At this point evaluate the cause of power loss. If it was fuel starvation and you have available fuel, you may
consider a restart attempt. Control may become marginal during restart attempts made at night or in weather.
If you have decided not to restart, or the attempt failed, finish the cleanup when time permits. Turn off the fuel
to the dead engine and close its mixture and cowl flaps. Turn off the magneto switch caution; listen for a
change in sound as you switch through the "left" and "right" positions. You might just have grabbed the wrong
switch.
If you have additional time and leisure, dig out the book and refresh yourself on emergency systems operation
and reevaluate all that you have lost. The descent and landing are the same as normal unless the manufacturer
says otherwise. If the approach will be on instruments, do not lower the gear until you are on final approach
inbound. If you cannot get the-flaps down, continue with normal airspeeds for a normal no-flap landing; again,
no "cushion."
Do not forget to retard power as you begin your descent. It is very normal for a pilot under stress to fly faster
speeds than usual. This extra speed will impair judgment and will be more difficult to dispose of when the
need arises. Use what is required and not a knot more.
69
The last item is the most ticklish from an advocacy standpoint: What if the propeller will not feather?
I said earlier that you should stop it, as the drag is excessive. If your proficiency permits, you should do just
that. This is possible only by deliberately approaching Vso. This is initially going to cost altitude, perhaps a
thousand feet, because you must retard power significantly on the good engine to avoid loss of control. If this
is your only choice, proceed as follows: Retard power on the good engine to around 17 inches. As the air speed
decreases through the flap operating range, lower half flaps. Maintain altitude until the airspeed reaches Vso
plus five knots. Maintain this airspeed and allow the aircraft to descend. If the windmilling propeller is going
to stop, it will-now.
Once the prop stops, lower the nose and blend in climb power on the good engine. Do not exceed Vxse until
you are sure the prop will not windmill again. If you can reach Vyse without windmilling again, fine. Do not
go any faster. Retract the flaps you lowered as you approach Vxse, or earlier if able. The hazards of this
operation are obvious, but the advantages could outweigh them, especially in mountainous terrain.
Multi-engine flying should be safer than single-engine flying, and it can be. But it is only as safe as you
habitually make it. If you normally pick up the gear and retard to climb power as soon as you are airborne, you
are setting yourself up.
Have a plan and some definite rules. If you lose an engine (or two—it happened to a friend of mine), it will
occur at the engine's choosing, not yours or your instructor's.
Periodically got some dual in basic multi-engine techniques. This will help you evaluate your own proficiency
and correct it as necessary.
The foregoing rules are not chipped in stone. You have to fly the airplane you're in, from the airport where you
are. When you graduate from the go-when-it's-blue single-engine class into night, IFR, and multi-engine
operation, you have left the amateur field for the professional. You had bloody well better train, think, and act
like one, or sooner or later you will be in trouble.
The Author
Edwin W. Lewis, Jr., of Castro Valley, Calif., has no idea of the total flight hours he has racked up since he
started flying in 1951, but he has logged about 6,000 hours of instructing time. He became a part-time civilian
instructor after four years with the U.S. Air Force at Valdosta, Ga., first as a pilot and then as an instructor,
and one year in Southeast Asia flying a Cessna L-19. He holds all ground and flight instructor ratings except
rotorcraft, plus flight navigator and flight engineer time. He has been active in the AOPA flight training
program, instructing at 17 clinics thus far. Lewis graduated from Hobart College, Geneva, N.Y. He obtained
his commercial ticket while a student there.
70
Single vs Twin—Which is Safer?
(From FAA Aviation News/March - April 1991)
Spring has sprung (in most of the country, that is), and it is the time when a pilot's fancy turns to doing more
flying in the balmy air. Spring is the time when new plants sprout, new animals are born; so perhaps you have
considered having your certificate 11 grow" a new rating. Perhaps that new rating you are considering is a
multiengine class rating. You have heard other pilots remarking that it only takes a few hours to earn, and
there is no requirement for a written test. Why not? A few hours in the air in a 11 real" airplane, and you walk
away with an authorization to fly airplanes with more than one engine. Besides, everyone knows two engines
are better than one-right? — Editor
According to an old saying, "There is safety in numbers." If the saying is true ' if one engine is safe, are two
engines twice as safe? The following short, simple, single-versus-twin-engine pilot test may help you decide.
The test is designed to test your knowledge of safe operating procedures for one and two engine light general
aviation aircraft. Depending on your number of correct answers, you may be: a passenger, a student pilot, a
pilot, or an aircraft survivor. Match the following questions with their correct answers. The correct order is
given at the end of the article.
Questions:
1. When are two engines better than one?
2. Why have two engines?
3. When is one engine better than two?
Answers:
a. When you crash.
b. So you can pick the spot for an emergency landing.
c. When one quits.
d. I don't know/I don't care.
Score based on the number of correct matches:
0 = passenger; 1 = student pilot; 2 = pilot; 3 = survivor.
The questions are variations of the single engine versus the light-twin-engine aircraft controversy pilots have
argued about since Orville Wright made his first flight in a single-engine, twin-prop aircraft. Each question
contains an important safety message for pilots of both single and light-twin-engine airplanes.
Although two engines provide a twin-engine aircraft a degree of safety through redundancy, that safety factor
can be offset by the pilot's lack of knowledge about light twin operating characteristics. Misconceptions about
"two are better than one" have caused many pilots grief. The reason is simple. Most light twins (for the
purpose of this article, those under 6,000 pounds gross weight and/or with a stall speed of 61 knots or less)
lose about 80 percent or more of their power when an engine fails, rather than the 50 percent one would
expect. That 80 percent or more power loss is why, under certain conditions, a light twin may only have
enough power after an engine failure for the pilot to pick a spot for an emergency landing. The aircraft may
not have enough power to hold altitude or fly safely on only one engine.
The problem is some twin pilots may decide to risk continued flight when the safest decision may be a
controlled emergency landing in a place of their choosing rather than risk an out of control crash. Singleengine pilots do not have the same type of problem. Their decision process is simple. They lose an engine;
they land!
Since an engine failure can ruin any pilot's day, the following is a review of some practical takeoff safety tips
for those pilots who may not have flown much during the winter. Maybe some of the ideas will help some
pilot prevent an engine-out emergency or at least minimize the risks of one. The survival key for both single
and light-twin-engine pilots is their flight planning before the engine starts, not after it stops.
71
As in any article discussing flying ideas and safety tips, the pilot operating manual is the authoritative guide
for the safe operation of a specific model of aircraft.
According to the latest available National Transportation Safety Board (NTSB) general aviation safety report,
Annual Review of Aircraft Accident Data for General Aviation Calendar Year 1987, the two most dangerous
first phases of flight during the period 1982 to 1987 were takeoff and landing. Landing was the most
dangerous accounting for about 25 percent of the accidents, and takeoff was second at about 20 percent. This
article will focus on takeoff techniques with special emphasis on twin-engine operations, since FAA Aviation
News recently published a story on landings titled "The Stabilized Landing Approach." (May-June 1990).
The first flight planning step for any flight is a review of the aircraft's performance data. The data provide
takeoff, en route performance, and landing information needed by the pilot in deciding if the flight can be
flown safely. When reviewing and using the performance information, each pilot should use very conservative
estimates for the takeoff distance and climb performances listed in the operating manual. The average pilot and
your basic used aircraft may not be able to match the handbook's performance information.
After reviewing the performance data and computing weight and balance information, each pilot must decide
if it is safe to takeoff, fly en route, and land at the destination airport after considering such environmental
factors as density altitude, wind direction, obstacles, and runway conditions such as length, slope, and type of
surface at both the departure and destination airports. The information will also help satisfy the requirements
of FAR 91.103, Preflight action, which states in part, "Each pilot in command shall, before beginning a flight,
become familiar with all available information concerning that flight." The FAR then lists specific aircraft
performance, airport, and runway requirements.
In addition to the normal flight planning requirements, a twin pilot must also determine if a safe flight can still
be made after losing an engine. In many cases after losing an engine, a light-twin-engine aircraft cannot, or
should not, continue the flight because of the loss of power and such adverse environmental conditions as high
density altitude, high terrain, or IFR minimum enroute altitude requirements that can often exceed the aircraft's
single engine capabilities.
As part of each preflight planning session every pilot should also determine the minimum runway length
needed for takeoff. In some cases, such as high density altitude, the minimum length needed may almost equal
or exceed field length. A safe pilot may decide this is an unacceptable risk. If the runway length is adequate,
the horizontal distance needed to climb to a safe maneuvering altitude, not just the distance to clear the
standard FAA 50-foot tree at the end of the runway, should also be calculated. Under some conditions, such as
high density altitude or airport elevation, some aircraft cannot climb fast enough or high enough to avoid some
of the obstacles near some airports around the country.
Because density altitude is one of the most important factors in determining an aircraft's performance and
ability to fly, it should be calculated before each flight to ensure adequate aircraft performance. High density
altitude can reduce an aircraft's capability below acceptable safe limits. It can also destroy what little singleengine capability a twin aircraft may have. But how many pilots routinely compute density altitude (DA) or
even remember what information is needed to compute it? (DA is pressure altitude corrected for non-standard
temperature using either a flight computer or chart. Pressure altitude is the altitude read on an altimeter when
29.92" is set in the altimeter setting [Kollsman) window.)
After computing density altitude and runway takeoff distance, another important flight planning item each
pilot should (as some operations require) compute is the aircraft's accelerate-stop (A/S) distance. A simple
definition of the term is that distance needed to accelerate an aircraft to rotation speed, for the aircraft to lose
power at that moment, and then for the pilot to be able to stop the aircraft on the remaining length of runway
based upon airport conditions and aircraft load. The A/S decision point is what separates single-engine pilots
from multiengine pilots. UP to A/S, each type of aircraft can stop on the runway. After A/S and up to a certain
72
altitude a single-engine aircraft is off the runway and into something, be it grass, fences, trees, or houses.
However, a twin pilot may be able to continue the takeoff and return for a safe landing. The key word is may.
For, like their single-engine counterparts, sometimes the safest decision twin-engine pilots can make is to
execute a controlled, survivable landing off the runway in a place of their choosing rather than risk trying to go
around in an aircraft that can not safely fly. The only way to know if your aircraft can safely takeoff with only
one engine operating is by understanding your flight manual and your own operating techniques and aircraft.
Some flight manuals provide detailed performance information that can be used to compute continued takeoff
capabilities with only one engine operating. Just be sure you have read and understand all of the small print
that explains the specific conditions that apply. If your manual does not list the information, maybe your
aircraft is not capable of continuing a takeoff with only one engine operating.
The A/S point is arguably the most critical decision point in the twin pilot's GO/NO-GO decision process. The
number of decisions a twin pilot has to make at the A/S and later during the takeoff procedure, such as making
sure Vmca, minimum controllable airspeed, plus a suggested safety factor of at least five knots or the
manufacturer's recommended speed is reached before rotation, knowing Vx and Vy for both single engine and
normal two-engine operations, and being able to control and fly the aircraft with only one engine operating are
what make flying twin-engine aircraft so complex.
Understanding and calculating A/S distances are not enough. Pilots should prepare themselves for possible
takeoff emergencies by reviewing their aircraft's emergency procedures. One good review technique is the
"what if" scenario. Pilots can prepare for any possibility by asking such "what if" questions as, "What if I lose
an engine" and then reviewing the correct procedure and options. Valuable time can be saved during an
emergency if the pilot has memorized the important emergency checklist steps as part of the initial aircraft
checkout. Once the emergency situation is under control, the pilot can then review the complete checklist to
make sure every item is done.
After reviewing all the flight planning steps and going out to the aircraft, the best way for any pilot to avoid or
minimize an engine problem on takeoff is a careful preflight and ground check using a checklist.
And the ground check does not stop with only an engine run-up. Every pilot should check to see if their
aircraft is developing full power early in the takeoff roll. By detecting a power problem early in the takeoff
roll, the pilot can abort the takeoff before passing the critical A/S point. The power check is done in two easy
steps. First, the pilot checks the aircraft's instruments for proper indications. Obviously this means the pilot
must know the aircraft's normal indications. Then the pilot cross-checks the instrument readings against an
"outside" reference. The check is made by comparing how much time or distance the aircraft normally needs
to accelerate to rotation speed to the current takeoff roll. If after the normal amount of elapsed time or distance
is used (distance can be measured by runway distance markers, a tree, brush, or some other point along the
runway) and the required airspeed is not obtained, the pilot should abort the takeoff and find out why. The
time to abort a takeoff is before the aircraft runs out of runway, not after it runs off the runway or into the
trees. The importance of aborting a takeoff when something is not right cannot be over emphasized. Lives
have been lost when takeoffs were not aborted.
A well publicized case of an aircraft not producing enough power to takeoff and fly was the Air Florida B-737
crash at Washington National Airport on January 13, 1982. After liftoff, the aircraft hit a bridge near the
airport and crashed into the Potomac River. Seventy passengers and four people on the bridge were killed in
the accident. The National Transportation Safety Board's report listed as one of the probable causes of the
accident the "... captain's failure to reject the takeoff during the early stage when his attention was called to
anomalous engine instrument readings." (Editor's note: Snow and ice were major factors in the accident.)
As the example shows, not only is it important to be able to determine if an aircraft is developing enough
power to take off and fly, it is equally important to know how much distance is needed to stop it safely. This is
73
why an aircraft's accelerate-stop distance is so important. This distance is what separates the single-engine
pilot's limited choices from the twin-engine pilot's options.
A single-engine pilot has few choices after passing the A/S point and having an engine failure. In most cases
the only choice is selecting what not to hit. This is where prior planning is important. A safe pilot, either from
being familiar with the local area, or having reviewed the airport environment before landing, should know the
best emergency landing spots straight ahead (making only slight turns to avoid obstacles) off the end of the
active runway, considering such things as, power lines, obstacles, trees, open areas, houses, fences, roads, and
the location of high population sites, such as schools, near the airport. The safe pilot will then have a plan
ready in the event of any type of emergency.
Like their single-engine counterparts, twin-engine pilots can also make a controlled emergency landing
straight ahead. Unlike their single-engine counterparts, twin-engine pilots may be able to continue their takeoff
on one engine and return for a safe landing. The key word is may.
The problem is most light general aviation twins are not required to hold or gain altitude with only one engine
operating. And that one operating engine may not be producing even the limited performance listed in the
aircraft's operating manual since engine performance decreases over time. (This is the basis for the saying
about being able to pick the spot where you want to crash,) Because of a twin's limited performance with only
one engine operating, its pilot must also use the correct single-engine techniques to fly the aircraft to have any
chance at all for a safe flight. Anything less than perfect technique can result in loss of altitude, control, or
both.
No matter how well both twin- and single-engine pilots do their flight planning and preflight their well
maintained aircraft, accidents will continue to occur during takeoff. Engines will fail. Pilots will lose control.
Accidents will happen. To reduce those risks both during takeoff and later phases of flight, pilots must
understand their operating environment; their aircraft's performance and operating systems; and their own
flight skills and abilities when deciding on a safe or survivable course of action when confronted with an
emergency. In some cases, a wise pilot may decide to either delay the flight, reduce the aircraft's load, or
modify the route of flight to avoid or minimize the risks of a takeoff or en route engine out emergency, even if
the aircraft does have two engines. Because they know there may be times when even two engines are not
enough insurance for a safe flight.
But, whether you fly a single, or twin-engine aircraft, hopefully, this article has provided you with some
interesting safety ideas to think about. Regardless of the number of engines on your aircraft, the best insurance
policy you can buy for a safe 1991 flying season is a thorough flight review with' your local certificated flight
instructor (CFI). A flight review is especially important if you have not flown recently, or if you are not
current in type. (The CFI must also be current in the aircraft used for the checkout.) In addition to ensuring a
safer pilot, the checkout could also meet the pilot's requirement for a biennial flight review and/or the flight
portion of the pilot's next set of "Wings." ("Wings" is the FAA's Accident Prevention Program's Pilot
Proficiency Award Program.) One of the things you may want to discuss with the instructor is how to calculate
your own accelerate/stop distance. If you have access to a long runway, with your aircraft at gross weight and
using your normal takeoff technique, accelerate to rotation speed and then abort the takeoff and stop. The total
distance from your start point to where you stopped is your rough A/S distance. To add an element of surprise
to the test, have the instructor pull the power at rotation speed and note the distance. The distance should
increase by several hundred feet because of your normal reaction delay. Once you have an estimate of your
personal A/S distance, always add some distance for the unknown. Remember that rolling takeoffs add
distance to A/S distances. Always leave yourself an out.
If you are flying a twin, after you have determined your own A/S distance, take advantage of the instructor's
presence by testing you and your aircraft's ability to execute a single-engine go-around. Simulate a singleengine go-around at a safe altitude and see if your aircraft and skill will allow a successful go-around. Some
aircraft are not capable of making a safe single-engine go-around. One FAA safety pamphlet says a single-
74
engine go-around may be impossible unless you have several hundred feet of extra altitude above the terrain
and an airspeed above Vyse. The situation is particularly critical it you lose the engine during a normal goaround.
The moral of the story? Listening to a lot of hangar flying about light twins is not what sharpens your edge in
flying them. The only way to minimize the risks in any kind of flying is to learn, learn some more, and learn
again. Flying multis is fun and challenging, but never, ever take that extra engine for granted.
And it does feel so good to see these words on your certificate: Airplane-Multiengine Land.
The following sources provided ideas and information for this article: Mr. George Lutz of Springfield, VA; the
FAA's Accident Prevention Program's pamphlets titled, "Planning Your Takeoff" and "Flying Light Twins
Safely;" the FAA Flight Training Handbook; and the NTSB Aircraft Accident Report NTSB-AAR-82-8.
Correct quiz answers: 1c, 2b, 3a.
75
Commentary - Insights
Youth's optimism is incredible. Someone else said it best: "Young men make the best fighter pilots because
they're too stupid to realize they can kill themselves."
I was looking at an old logbook when I came across my first encounter with multi-engine airplanes. Flight
training - there was no ground training - and the checkride took all of 6 hours, 40 minutes in a Piper Twin
Comanche. Two months later, with no additional multi-engine time, I logged a 1-hour checkout in a six-seat
Aztec so I could fly my parents, my brother, and our two girlfriends to Las Vegas.
Zoom, zoom, zoom - how cavalier, exciting, lucky, and downright stupid. Looking back on those times makes
my knees weak. Lots of pilots were killed in Twin Comanches during that era, and I suspect that their training
was about as thorough as mine. In hindsight, the Twin Comanche was and is a great airplane, providing you
were taught the truth about multi-engine flying. I wasn't.
Today, we spend far more time with our multi-engine students, and we certainly spend considerable time in
the classroom discussing multi-engine flight characteristics, systems, and operating procedures. Even with this
effort, I still encounter pilots who do not have a practical understanding of the airspeed indicator's blue-line
and red-line reference speeds. They're in the same boat that I was with the Twin Comanche.
Blue Line
The blue line on a multi-engine airplane's airspeed indicator is a performance speed, pure and simple. It
represents VYSE, the single-engine best rate of climb speed. If the airplane will not climb at blue line, and
many will not with one engine shut down, continued use of blue line will minimize the ensuing descent rate.
Performance speeds, published in the pilot's operating handbooks (POH) for all airplanes, are used for various
types of maximum-performance climbs. These speeds have absolutely no relation to descent performance.
Why then, do some multi-engine pilots believe that blue line is a final approach speed when performing a
single-engine (one engine inoperative) approach and landing. This is a gross misconception. Always use the
normal final approach speed recommended by the POH (a speed below blue line) when in landing
configuration and on final approach. To fly approaches too fast results in floating - the excess airspeed must be
dissipated - and long landings.
Many pilots who fly a number of multi-engine airplanes argue that blue-line thinking is acceptable for singleengine approaches because it's safe and it eliminates memorizing excess numbers. That is true, providing they
always operate on long runways, but most of these pilots are moving up the aviation ladder. When they
transition to jets, limited runways become a common occurrence, and the pilot who has not learned to use the
proper approach speeds is in for a rude awakening.
It gets back to basic habit patterns. Establish the correct habits early in your flying career so that future
evaluators will recognize your ability to perform correctly, a prerequisite for the better-paying jobs. Assume
that every runway is of limited length, use the correct speed for every normal and single-engine approach, and
land on the numbers. Practice makes perfect.
The go-around is another point used by advocates of blue-line approaches. They feel the blue line keeps them
in better position for a single-engine go-around, a maneuver that mandates using the blue-line airspeed. That
concern is unfounded.
At a safe altitude, set up a simulated single-engine approach (one engine at zero thrust) with gear and full flaps
extended. On short final, go around. Select full power and the appropriate amount of rudder for directional
control, retract the flaps from FULL to APPROACH or as the POH recommends, and glance at the airspeed
indicator. If you maintained the previous approach attitude up to this point, the airplane is already at blue line,
76
maybe faster. Now establish the blue-line climb attitude, and upon confirming a positive rate of climb, retract
the gear, the remaining flaps at the appropriate time (see POH), and complete the appropriate clean-up items.
Many times you may find that the combination of density altitude and your airplane's performance will net you
surprisingly poor performance. Remember this if you're ever faced with a potential single-engine go-around.
Make sure to announce your priority handling and fly your approach to avoid the single-engine go-around.
This acceleration technique is my reason for making the previous statement that climb performance speeds
don't apply to descents. If the pitch attitude is in the normal, nose-down approach attitude, the airplane will
quickly accelerate when power is applied to the operating engine and the last increment of flaps is retracted.
A word of caution applies to single-engine go-arounds in light twins. If an engine has been shut down for real,
not just simulated for training purposes, declare an emergency before accepting an actual single-engine goaround in a heavy airplane.
You're the final authority for the safe operation of the airplane, and single-engine go-around performance can
be a questionable factor. Use emergency authority to avoid compromising safety, and if necessary, land on a
clear portion of the runway, or even a clear taxiway. Ensure that you check your performance charts, which
may show that a single-engine climb is impossible in the current conditions. Go, if possible, for a long,
controlled runway.
Red Line
The red line at the slow-speed end of a multi-engine airplane's airspeed indicator is a control speed. It
represents VMC, the minimum speed for maintaining directional control when an engine suddenly fails under
the most adverse conditions.
In addition, VMC represents a control application speed. If flying above red line, conventional engine failure
procedures are used - control the airplane, increase power, identify, verify, feather, and refer to the checklist.
Below red line, or when near red line and the airplane starts behaving strangely, immediately reduce the power
if an engine fails and establish a nose-low, power-off, gliding attitude. If altitude permits, regain blue line,
slowly add power to the good engine, and initiate a single-engine climb.
When do we fly near or below red line? Only during training flights when at or above 3,000 feet above ground
level (AGL). Power-on and power-off stalls (departure and approach-to-landing stalls) are once again required
for multi-engine certification in the new commercial pilot Practical Test Standards (PTS). The FAA has
reinstituted the stall series that was taught for years, and it wisely discarded constant-altitude, imminent stalls,
a maneuver that did nothing for students' stall/spin awareness, insights, or confidence. We're back teaching
proper multi-engine skills, and that means flying at speeds well below red line for training purposes only.
Through the late 1960s, engine failures were initiated during all phases of flight. Today's instructors do not fail
an engine below the minimum safe single-engine speed, VSSE, an unmarked minimum speed that is denoted in
most POHs.
All of these changes were prompted by the Twin Comanche. If an engine was intentionally failed at too slow a
speed, or if the engine-inoperative loss of directional control demonstration (VMC demonstration) was
performed at an altitude where VMC was below stall speed, the stalled condition and the thrust differential
would cause the airplane to violently roll and pitch. All twins will do this; the Twin Comanche could enter an
uncontrollable flat spin.
While stall speed remains relatively constant below 10,000 feet, normally-aspirated engines' power decreases
with altitude. With less power available at altitude, the amount of assymetric thrust is also reduced. This, in
turn, lowers VMC to below stall speed if flying high enough.
77
If pilots immediately chopped power when the stall warning horn activated, the pre-stall buffet occurred, or the
actual stall and initial roll occurred, recovery was easy. At idle power, a stalled multi-engine airplane is no
different than a stalled single-engine airplane. Reduce the angle of attack, and in this situation at 3,000 AGL or
better, make a power-off recovery.
After the glide is established, continue to maintain that nose-low descent attitude, advance both throttles, use
rudder to maintain directional control, and accelerate to blue line. Now establish the blue-line climb attitude
and complete your normal engine failure procedures.
Never forget this critical red-line rule: When flying near or below red line, and either engine hiccups or the
airplane starts an unsolicited roll, immediately chop the power and establish a glide. Red line is nonexistent in
a multi-engine airplane with idled engines, and spinning is impossible if the airplane is not stalled. Multiengine airplanes are not certified for spins.
Even though multi-engine flying is expensive, good training must be your first consideration, money your last.
Protect your life and do it right.
By Ralph L. Butcher
78
Recurrent Review - Give Me A Brake?
It was like one of those bad dreams -- the ones where no matter how hard you run, your legs just won't move
fast enough. The whole world is in slow motion, you can see everything happening, but you just can't react to
it. It was an old Cessna 310. I was in the left seat, and my student, working on his multi-engine instructor
ticket, was taxiing from the right.
"Come on, Andy, keep it on the centerline." Slowly the aircraft edged left to the yellow centerline on the
gently down-sloping taxiway. Then, just as it had come to centerline, it drifted to the right again. I didn't know
why he was having such a hard time. He was a good student, and generally a perfectionist, yet this was sloppy
work.
We drifted farther right; I decided it was time to get on the brakes and help. To my amazement, nothing
happened. "Pump the brakes, Andy!" We pumped to no avail; 4,000 pounds of airplane was going off the right
side of the taxiway.
For an instant I thought about increasing the power on the right engine to move us left, but we were already
picking up speed with the slope, and the end of the taxiway was approaching. The last thing we needed was
additional speed. The right tire was now in the grass; the added drag pulled us farther to the right. I pulled the
mixtures to idle -- the least I could do was prevent engine damage.
It was instrument weather that morning, and there wasn't anyone in the run-up area or at the hold line. Luckily,
there wasn't anyone on short final, either. I hit the brakes as we came to the taxiway's end. Only the right one
caught, of course, and we turned abruptly toward the active run-way. I figured we'd swing around and hit the
taxiway lights or the identification sign. In my peripheral vision I caught the motion of the left propeller.
Although the mixture was in idle-cutoff, the prop was still turning at about 500 rpm. In desperation, I hit the
bar that kills the mag switches in hopes that the prop would stop. Even at our slow speed, it was amazing how
much momentum we had. We crossed the hold-short line in a slow arc and headed off the taxiway stub. Then,
as if a giant hand reached down to help, the propeller stopped, and so did the old 310. Another 5 feet and the
left propeller would have hit a taxiway light.
"Ah, twin Cessna, do you need assistance?"
"Yes, sir, we've had a little problem here. Can you send a tug, please?"
We'd been lucky that morning. Had there been an aircraft in front of us, we would have either hit it or, with
our right brake, tuned into the ditch between the taxiway and runway. If an aircraft had been at the hold line,
no doubt we would have slammed into it, causing extensive damage. As it was, no damage was done.
Taxiing isn't something pilots practice, and most pilots don't treat it with the respect it deserves. But it's
something pilots should think about every time they get in an airplane. Taxiing an aircraft requires as much
diligence, planning, and awareness as any other phase of operation, especially in the event of an emergency or
in adverse conditions. Slick surfaces, sloping taxi-ways, prop or jet blast, wake turbulence, and strong winds
can all present unmanageable hazards; pilots should review taxi procedures periodically.
When preparing to taxi, the first thing I do is evaluate the winds. I also set the directional gyro and, if it has
one, I set the heading bug to the wind direction so I can quickly see from which direction the relative wind is
coming. This is very helpful in managing the aileron position during the taxi.
As the Practical Test Standards suggest, it's an exceptionally good idea to test the brakes prior to moving more
than an aircraft length. If there are two pilots, both should independently test each brake to ensure that all
79
systems are working. Of course, the brake check on our Cessna 310 revealed no problems, so remember that
problems can arise at any time, which calls for constant pilot diligence.
The need to taxi slowly cannot be overstated. I once watched an aircraft careen into a parked plane when it lost
traction on a snow-covered ramp. Until you've been in the situation, you don't realize the momentum of even a
slowly moving aircraft, and the meat cutter up front can cause a lot of damage to anything it hits. Remember
that on a bumpy taxiway, props with low clearance have been known to strike the ground, and extra speed only
worsens the prospects of a prop strike.
As an instructor, I believe it's important to present pilots, regardless of experience, with directional control
problems when taxiing. By placing gentle pressure on a brake with equal pressure on the opposite rudder, the
instructor creates a turning moment without any revealing rudder pedal movement. Instructors should watch
for misuse of the ailerons (steering), and proper reaction with throttle and brakes.
A variation of this scenario is to indicate that an aircraft is exiting an intersecting taxiway and that only one
brake works. This scenario creates an object lesson in momentum. Pilots quickly learn that the situation is
much more difficult to handle than expected, and usually they slam into the phantom aircraft.
A student taught me a valuable lesson on operating with one brake. I thought our Cessna 152 was going just a
bit too fast, so I said, "OK, there's a Citation coming out of Alpha-15, and only your left brake works."
Although an inexperienced pilot, this student was an experienced maintenance technician who had taxied all
types of aircraft. He closed the throttle, kicked right rudder until the nose wheel cocked in that direction, and
then applied steady pressure on the left brake. To my amazement, we came to a relatively controlled stop just
short of Alpha-15. The phantom Citation was undamaged.
The key to dealing with failed brakes comes in the surprise factor. If you know you have a failed brake and
have a moment to plan, you're better off than if it comes as a surprise. With this in mind, it's a good idea to
retest the brakes well before you approach an area or situation where they might be needed. If you find the
brakes don't work, you can shut down the engine and find the best available escape route.
Another good time for a brake check is right after touchdown. When practicing short field landings, pilots
often hunker down on the brakes as soon as the wheels touch. Imagine what would happen if one brake didn't
work -- the aircraft would careen off the runway at near flying speed. Since it would be better to go off the end
of the runway at slow speed rather than off the side at high speed, a more reasonable practice might be to test
the brakes before applying full braking power.
Pilots are generally taught to taxi with the nose wheel on the centerline. While this is usually a good idea,
particularly if you like to have wingtip clearance from stationary objects, there are times when being off
center-line is appropriate.
One good example is during winter, when slick, snow-packed, or icy conditions exist. Then it's better to keep
the main wheels on dry pavement, as long as there's adequate obstruction clearance. Be extremely cautious of
snow ridges or ice chunks on the taxiway. Even a slight amount of drag on one wheel can turn the aircraft
unexpectedly, and in slick conditions, the brakes often don't have much effect.
Especially in winter, when icy taxi-ways and run-up pads prevail, pilots need to maintain their awareness of
prop and jet blast, and winds that have been known to literally blow an aircraft off the runway. During the runup, try to get at least one wheel on dry pavement so the high power setting won't cause the aircraft to slide. If
you have a passenger or another pilot, have them watch outside while you do the run-up to ensure you don't
start moving.
80
Aileron and elevator position during rollout and while taxiing in strong winds is critical to prevent damage and
keep the aircraft right side up. I remember watching a beautiful old Rockwell 60 taxiing in a 40-knot tailwind.
It apparently wasn't registering with the pilot because he was struggling to pull the yoke back to keep his nose
up. That works well in the air, but when taxiing with a tailwind, the controls operate in reverse, and forward
pressure on the yoke is required to prevent the tail from lifting.
The harder the wind blew, the more the pilot pulled the yoke back. We watched in horror as weight lifted from
the main gear legs and the nose sank closer to the tarmac. Suddenly there was an audible ZZZIIPPPP and a
shower of sparks as the three-bladed constant-speed prop hit the ground. The pilot probably thought that after
landing in the strong winds he was home free, but his lack of awareness during taxi was the real problem. I
don't know the extent of the damage, but I'm certain it was costly. (See Flight Training Handbook, AC 6121A, pp. 51-56, "Taxiing.")
We've all heard the old adage, "Don't stop flying the airplane until it's tied down." Take heed, and don't let
your flight begin or end in disaster. As long as the engine is running, we need to keep our minds running,
anticipate problems, and stay mentally way ahead of the airplane.
Bob Rossier holds a single and multi-engine land ATP certificate, commercial single-engine seaplane
certificate, and instrument and multi-engine instructor certificates. He's an active flight instructor and an FAA
accident prevention counselor.
By Robert N. Rossier
81
Financial Flight Plan - Tax-Deductible Flying
How would you like to have a 15 percent, a 35 percent, or even a 50 percent discount on nearly everything you
pay for in your aviation training? Sound farfetched? In the right situation, there are tax breaks Uncle Sam is
giving many eligible pilots, including students, under federal tax law.
You are eligible if your flight training is work-related. The IRS rules say you can deduct work-related
education costs as ordinary and necessary business expenses if they serve a business purpose of your current
work and meet certain work, profession, or job requirements. It is important that the training must not qualify
you for a new job or occupation.
If you can meet these basic requirements, which will be covered in detail, then your flight training expenses
are probably tax-deductible as a miscellaneous educational expense deduction on schedule A of your 1040 tax
return, or if you are self-employed, schedule C or partnership Form 1065.
If you are eligible, what expenses can you deduct? Practically any expense related to your aviation training.
Here is a partial list: aircraft rental, instructor fees, simulator time, charts, subscriptions to magazines (like
Flight Training), flight equipment, such as headsets and instrument training hoods, test fees, medical exams,
aviation books, ground school, software/ video training courses, and auto mileage to/from the airport.
If you are training in your own plane, you can add these aircraft expenses to the list: maintenance, insurance,
hangar/ tiedown, depreciation.
How Much Is Deductible?
What percentage of these costs can be deducted depends on your specific situation. If you don't fly 100 percent
for business, how do you determine how much of your flight training costs could be deductible?
A commonly accepted method is to determine the percentage of business flying you did relative to your total
flying, not including flight training. Then pro-rate your flight training expenses by that percentage. If you flew
100 hours last year, not including any flight training, and 80 hours of it was for business travel, then 80 percent
(80 divided by 100) of your flight training might be deductible.
You don't have to work in aviation to satisfy the requirement that your flying is work-related. But your flying
should be shown to provide distinct advantages to your business, such as greater travel efficiencies, flexibility,
access to remote sites, carriage of company materials, or even expense savings over the airlines. As an
employee, you may be required to travel on company business to visit customers, company sites, conventions,
and meetings while you fulfill your sales, service technician, or management duties.
Some companies, which recognize the benefits general aviation gives their businesses, make having a pilot's
certificate a condition of employment. If you are not a pilot when hired, you are expected to start flight
training soon after you start the job with, for example, the aviation oil company that requires salespersons to
make sales calls in the company Beech Bonanzas, the aviation technical manual publisher that requires all
salespeople to have a private pilot certificate, or the midwestern truck wash equipment manufacturing
company that requires its company representatives to be able to fly to better cover their sales territories.
While these jobs are admittedly not easy to find, you can, as many have, sell your company on the benefits of
general aviation. How about a schoolteacher who is employed teaching aerospace education? How about an
aviation instructor in a high school or community college teaching ground school classes? What about a
professional pilot already involved with aviation as a career? All these employees, depending on their
circumstances and situations, are probably eligible to write off significant amounts of their flight training if
they can show a work relationship.
82
And if you're self-employed, you can show that travel is required in the normal course of your business, and
that use of an airplane was "helpful," then you are probably eligible to deduct significant amounts of your
flight training, too. Your flight training tax deductions would be particularly strengthened if, soon after or even
before you completed your training, you bought an aircraft to use in your business. Of course, the airplane or
helicopter itself would be tax-deductible proportional to its business usage.
What Is Deductible?
Certain types of flight training are ordinarily accepted as tax deductible with little question, while other types
would almost never be approved. Periodic training required by FARs or for enhanced safety, such as an
instrument rating, are generally easier to justify for tax deductions than initial pilot certificates. Training for
initial professional aviation certificates - commercial, certificated flight instructor (CFI), or airline transport
pilot (ATP) - are more difficult to deduct in most cases because they can qualify the individual for a new
occupation.
Here are general guidelines concerning some aviation training broken down into four levels of tax
deductibility:
I. Generally Deductible: Training required if you already use aviation in a business or job-related activity  Periodic Refresher/Recurrency Training
 Flight Instructor Certificate Renewal
 Flight Reviews
 Instrument Competency Checks
II. Probably Deductible: Training needed if it's anticipated you'll soon be engaged in a business or job related
aviation activity that would benefit from it  Aircraft Type Ratings
 Instrument Rating
 Multi-Engine Rating
 Seaplane Rating
 Instrument Instructor Rating
 Multi-Engine Instructor Rating
 Ground Instructor Rating
 Helicopter Rating
III. Possibly Deductible: Training that, under certain circumstances, may be considered helpful in performing
your required work duties  Private Pilot Certificate
 Glider/Balloon Rating
 ATP Certificate
IV. Unlikely Deductible: Training that qualifies you for a new occupation would not be approved as a taxdeductible educational expense  Commercial Pilot Certificate
 Flight Instructor Certificate
 Initial Ground Instructor Certificate
Record Keeping
Another requirement you must meet for educational deductions is adequate records. The IRS does not require
you to keep records in any particular form or by any special method. It only says you must have "adequate
records and sufficient evidence" that, in combination, can prove each element of an expenditure, to include
amount, time, place, and business purpose.
83
Your substantiation should include receipts, canceled checks, pilot logbooks, and course completion
certificates. It's also important to realize that you'll not only have to prove that you incurred the education
(flight training) expenses, but you'll have to show that the training has a business relationship with your job,
business, or profession.
Retain copies of relevant FAR currency requirements and all employer statements or policies concerning the
flight training and its relationship to your job or business duties. You must collect enough evidence and other
information to show that your training complies with either of the first two conditions outlined below and does
not comply with either of the last two conditions.
To be deductible, two tax conditions must be met, and two conditions must not be met. Your flight training
expenses are deductible if the training: (1) Maintains or improves your present work, professional, or job
skills; or (2) allows you to meet new requirements of your employer or the law, to keep your present job or
level of pay. But it does not: (3) Meet the minimum educational requirements for your present job; or (4)
qualify you for a new trade or business.
To understand how these "qualifications" apply to flight training situations, let's examine some typical
examples and their probable tax treatment based on the facts presented. Keep in mind that most situations are
viewed in context to surrounding circumstances, and tax laws are subject to varying legal interpretations.
Good, complete records are assumed and a must.
Example One: An aviation instructor with a ground instructor certificate is actively teaching aviation at a flight
school, a community college, or freelance. Would he be able to deduct the costs of obtaining a flight instructor
certificate?
Probably. Obtaining a CFI improves his skills as an aviation instructor, allowing him to advance within his
profession, which complies with condition 1 above. Since he already meets (just barely) the minimum
education requirements of an aviation instructor, having a CFI gives him the ability to provide a broader range
of aviation instruction, which clears conditions 3 and 4. He would be in a stronger tax position, however, if he
already had his CFI and was adding to it, such as an instrument instructor rating.
Example Two: A commercial pilot flying charter for a fixed-base operator (FBO) completes her ATP training
in a Cessna Citation jet. Would her ATP training expenses be tax-deductible?
Yes. She's already a professional pilot and qualified in the business of being a pilot-in-command of a
commercial aircraft. Her ATP training improves her skills required to carry out the duties of pilot. If she
completed her CFI training instead, would that be tax-deductible?
No. Her CFI ticket qualifies her for the occupation of aviation instructor, so she's tripped up by condition 4.
How about if she added her multi-engine and seaplane ratings instead?
Yes. That would be tax-deductible education, particularly if she would likely be doing some charter flying that
required that training.
Example Three: The pilot is the sole proprietor in the business of rebuilding auto windshield wiper motors. To
conduct his business, he's required to travel extensively and maintain close association with vendors, suppliers,
and attend industry meetings. So he bought a Bonanza. During substantial parts of the year, weather made
instrument flying required, so he completed his instrument rating. Is his training deductible?
Yes. The instrument rating was essential for the safe and efficient use of the aircraft. Requirements of
conditions 1, 3, and 4 are met. Knowledge of flying was one of the skills required by him in his business, and
84
since instrument training improved those skills, all of his instrument training expenses were deductible (per
Income Tax Reg 1.162-5(a)(1)).
Example Four: A handyman, real-estate investor buys a large, run-down commercial property. He personally
handles all property management while commencing the long process of refurbishment. Frequent, long, and
tiring road trips between his home and the distant property convince him to learn to fly and buy a Cessna 150
for that travel. Is his private pilot training deductible?
Yes. One of his job's requirements is to provide his own transportation to the work site. In this situation, using
an airplane in his business was not only "helpful," it greatly improved his ability to do his work. Because the
FARs required him to earn a private pilot certificate, conditions 1-4 are satisfied. If he gets his instrument
rating, is that training deductible?
Yes. While this training enhances his safety and reliability, which are good business reasons, it also meets the
requirements of conditions 1, 3, and 4, which is the only thing the IRS is interested in.
Example Five: A former Air Force pilot is hired by an airline with the stipulation that she obtain her flight
engineer certificate. Is this training tax- deductible?
No. She is shot down by conditions 3 and 4.
Example Six: A building supply sales manager occasionally rents a plane to visit customers. He's reimbursed
by his employer for those business trips. Before winter arrives, he decides to complete his flight review and an
instrument competency check to be sure he's safe and sharp. Is this recurrency/refresher training taxdeductible?
Yes, although not as an educational expense. Subject to the 2 percent limitation, this is an unreimbursed
employee business expense (Tax Form 2106). The deduction is typically proportionate to the amount of total
business flying done during the year.
All pilots, including students, who are familiar with the tax laws, keep good records, and adjust their aviation
activities as necessary, can write off a substantial portion of their flying expenses, including flight training,
from their state and federal taxes. But before you fill out your tax forms, seek the advice of a tax professional
who's well-versed in aviation.
Jay Knepp, CPA, is the author of Pilot's TaxLog and an active pilot. Thomas Kiernan, CFII/MEI, is the author
of the AVTAX ADVANTAGE, a tax software program for aircraft owners and pilots.
Note: This article is of a general nature and should not be acted upon without consulting with a tax
professional who is familiar with aviation.
By Thomas Kiernan
85
Learning Experiences - Engine Failures
The single-engine Beech 23 Sundowner had just departed Runway 36 at Jeffersonville, Ind., and was on the
initial climb out when the engine lost power, but not quite. The aircraft turned left at low altitude and seemed
to be maneuvering to Runway 14. While lining up with the runway, the aircraft entered a steep left bank, then
abruptly rolled right and crashed. All four persons in the aircraft were killed.
A post-accident investigation of the aircraft found that one magneto was loose and one cylinder had a
substantial crack and exhaust valve leak. Investigators determined that the crash was caused by an inadvertent
stall while the pilot attempted to maneuver the aircraft.
Although modern aircraft engines are extremely reliable, engine failures still account for roughly 22 percent of
all general aviation accidents. Approximately half of these are the result of non-mechanical problems, such as
fuel starvation and carburetor icing, and are therefore easily preventable.
But statistics are of precious little comfort when the welcome roar of the engine is suddenly replaced by stark
silence. It's an absence of sound that will make the hair stand up on the back of your neck and twist your
stomach into a knot. And, as the preceding accident report shows, even a partial power loss, the cause of
roughly 4 percent of all general aviation accidents, can be a deadly challenge.
Failure Avoidance
The best way to deal with a powerplant problem is to avoid it entirely. This can, to some extent, be
accomplished through good maintenance, preflight procedures, careful planning, and the use of checklists. But
once a problem develops, the best course of action will depend on several factors: the type of aircraft (single or
multi-engine), altitude, the symptoms of the engine problems, and the conditions under which the problem
occurs.
There is a big difference between an engine failure in a single and in a twin. Unless the single engine is
restarted, a forced landing is imminent. In a twin, the pilot must make some important decisions, such as
whether to shut down or attempt to restart the failed engine, and may ultimately have more options than the
pilot of the single. In either type of aircraft, the eventual outcome of the situation will depend largely on the
pilot's skill and judgment. In all cases, such an event demands immediate attention.
Possibly the most important consideration in dealing with an engine problem is the altitude at which it occurs.
If an engine failure occurs at low altitude, such as immediately after takeoff or on approach for landing, there
may be little time for troubleshooting or the completion of checklists. In these situations, the pilot must focus
on flying the aircraft and maintaining control until the aircraft comes to rest. The pilot of the Sundowner found
himself in just that situation.
Altitude Bank
The more altitude you have when all goes quiet, the more reflective you can be about the situation and the
more you can do to avert the possibility of a forced landing. If a forced landing must be made, more altitude
may mean more choices in terms of your landing site. Unfortunately, in the following accident, the pilot was
unable to troubleshoot an easily remedied problem.
The newly certificated private pilot was taking a friend for a pleasure flight in a rented Cessna 172 near
Sanford, N.C. After about an hour, the pilot returned to the airport. While turning onto the base leg, he
misjudged the descent and added power to compensate. The engine did not respond to the increased throttle
setting, and the pilot was unable to make it to the runway. The pilot made a forced landing in a plowed field,
where the aircraft nosed over and was substantially damaged.
The engine was inspected and run in a post-accident investigation. It operated normally. The cause of the
accident was determined to be carburetor ice, which formed because the pilot didn't use carburetor heat during
86
descent and at reduced power settings in the traffic pattern. The carburetor heat was still in the "cold" position
at the time of the crash.
Inadequate training in the use of carburetor heat, and in the problems of carburetor ice, was determined to be a
contributing factor to the accident. Perhaps the use of a checklist would have averted this minor disaster, but in
an emergency situation, even checklists can cause problems for the pilot.
Checklists are an essential safety item for any aircraft, and should be used religiously. In effect, they are "do
lists." However, some checklists for dealing with an engine failure can leave a lot to be desired, at least in
terms of the sequence of actions specified. Following some, you'll be ricocheting around the cockpit like a
stray bullet, with little chance of hitting your target.
Quick Study
A quick study of the causes of an engine failure can, however, be useful in developing a coherent plan of
action. Combined with a little bit of know-how, we can establish a sensible, rapid-fire approach to dealing with
an engine problem. By developing such a plan and anticipating engine problems, we're much better prepared to
successfully deal with an emergency.
The most common reason for an engine failure is lack of fuel - either due to mismanagement or starvation.
With this in mind, one of the first actions to be taken in the event of an engine failure is to turn on the boost
pump, if the aircraft is so equipped, and switch to another fuel tank if there is one. Once these actions are
completed, it may still take 30 seconds or more for the engine to restart - seconds that may seem interminable.
Another likely problem, as illustrated by the preceding accident, is carburetor or induction system icing.
Again, the solution is simple: Apply carburetor heat or alternate induction air. An improperly adjusted mixture,
particularly following a descent, is easily remedied by adjusting (in this case enriching) the mixture. An
unsecured primer control can also precipitate a rough-running engine by allowing raw fuel to flow to the
engine intake, so check to make sure it is in-and-locked.
Finally, magneto problems are also on the list of potential suspects in an engine failure. Remember that a
misfiring magneto can decrease power, so if both magnetos are ON, try turning them off one at a time to see if
engine power and smoothness improves. (Don't leave the ground if the mag check isn't within checklist
tolerances.)
Going With the Flow
Troubleshooting an engine problem and attempting a restart sounds like a lot of work, and you might think it
would take a long time and present a major distraction to the primary business of flying the airplane. The truth
is, all these actions can be accomplished in much less time than it takes to read about them.
To complete the task quickly and efficiently, airline and other professional pilots use a flow pattern, a logical
series of actions to accomplish a given task or complete a checklist. Instead of bouncing around the cockpit
like a ping-pong ball, following the flow takes you through the procedure in an orderly fashion, minimizing
the possibility of missing an important item.
The flow pattern can be done quickly from memory, and then rechecked by following the appropriate checklist
if time and altitude permits. Although flow patterns are generally used in more sophisticated aircraft, the
concept applies equally well to relatively simple piston singles.
For example, a restart flow for a Cessna 172 might start on the floor between the seats by checking the fuel
selector valve. From there, move upward and check the mixture. Then move to the left, checking throttle,
carburetor heat, magnetos, and engine primer, all in sequence. Following this pattern, the restart procedure can
be accomplished in just a couple of seconds. With a little practice, you can almost do it in your sleep.
87
Essential Time
Particularly at low altitude, the key to success is reacting immediately to the problem, rather than becoming
reflective about it. As the following accident report points out, if you wait too long before dealing with the
problem, it may be too late to resolve it successfully.
An instructor was giving an instrument-rated private pilot a checkout in a Cessna Turbo 210 in Upland, Calif.
They had just returned from a training session and were in the traffic pattern when the engine suddenly quit.
The aircraft lost about 300 feet before the instructor finally took control. By that time, they could barely reach
the runway. The aircraft touched down in a nose-and-left-wing-low attitude. The nose gear collapsed and the
aircraft crashed into a parked aircraft. A third person riding in the 210 was seriously injured in the accident.
The investigation of this accident revealed that the fuel selector was set to the left tank, which was empty. The
right tank had roughly 20 gallons of fuel remaining. Again, use of the Before Landing checklist should prevent
such a problem. But once the problem develops, a quick response to the symptoms or the use of a restart flow
might restore engine power, or at least avoid a botched landing.
Not all engine failures are characterized by an abrupt silencing of the engine, and an observant pilot may be
able to spot a developing problem in time to make a precautionary landing. For example, sometimes a power
failure is preceded by an increase in oil temperature combined with a corresponding decrease in oil pressure.
Oil spraying on the windshield is another sure sign of a serious mechanical problem in the making. But other
problems may occur more quickly, or demand an immediate off-field landing. Smoke and flames emanating
from the engine cowling are indications of a fire, and most likely will necessitate shutting down the engine. A
severe vibration may signal a mechanical problem, such as a prop failure, also requiring an immediate
shutdown of the engine.
If these types of problems develop, all the checklists, procedures, and good intentions in the world won't make
the engine restart. When that happens, the pilot's only option may be an immediate landing. In the next
Recurrent Training, we'll examine forced landing accidents, and look at the factors involved in making a
successful emergency landing.
Bob Rossier holds a single and multi-engine land ATP certificate, commercial single-engine seaplane
certificate, and instrument and multi-engine instructor certificates. He's an active flight instructor and an FAA
accident prevention counselor.
By Robert N. Rossier
88
Form and Function - Adjustable Screws
Fixed-pitch propellers have a problem: They offer optimum performance at just one airframe/ airspeed/engine
power setting. All other combinations are a compromise. A fixed-pitch prop that gives a good rate of climb
provides less-than the optimum cruise speed. A prop that gives good cruise speed has less-than-stellar climb
performance.
To make optimum use of an engine's power during all phases of flight, a propeller's pitch needs to change. The
first variable pitch props were adjustable only on the ground. Once the adjustment is made, the prop then
operated as a fixed-pitch prop in flight. Used on many radial-engine aircraft such as the Stearman biplane, the
"ground-adjust-able" prop gives a good match between the prop and the most preferred flight condition, high
cruise speed or good climb performance.
The next evolutionary variable-pitch step was the two-position prop. Controlled from the cockpit, the prop
could be set at either full-low or full-high pitch in flight; no intermediate positions were possible. Twoposition props have counterweights that move the blades to high pitch while oil pressure moves the prop to
low pitch. Low pitch is selected for takeoff and climb, then changed to high pitch for cruise. The first practical
cockpit-controllable props were probably the Beech Roby props. Controlled either electrically or
mechanically, they could be set at any pitch position.
Today's constant-speed props are really a combination of a two-position variable-pitch prop and a propeller
governor that varies the propeller blade angle in flight to maintain a constant engine/prop rpm. The prop is
continuously variable from full-low to full-high pitch positions. The governor has a built-in constant speed
feature that regulates the oil pressure sent to the prop head by the governor. This oil pressure determines the
pitch of the propeller blades.
The advantage of the constant-speed prop is that it adjusts to maintain a nearly ideal prop angle of attack
throughout the aircraft's speed and power range, thus optimizing aircraft performance. There is a substantial
price to be paid for this performance optimization, however, in increased cost, maintenance, and weight.
Governing Two Twists
The in-flight operation of variable-pitch props depends, in part, on aerodynamic twisting force and centrifugal
twisting force. The props are designed so that the blades' aerodynamic center of pressure (which creates the
aerodynamic twisting force) is located ahead of the prop's pivot point (the prop hub). This force drives the
blades to high pitch. As the prop spins, centrifugal twisting force drives the blades to low pitch. The
centrifugal twisting force typically overcomes the aerodynamic twisting force, so the prop tends to go to low
pitch.
Two different constant-speed props are generally found on today's general aviation aircraft. McCauley props,
seen primarily on Cessna and Beech aircraft, use oil pressure to move the prop blades to high pitch and a
spring and centrifugal twisting force to move the blades to low pitch. Pipers most often use Hartzell props, of
which there are two types - steel hub and Compact. Oil pressure sets high pitch in Compact props while
centrifugal twisting force drives the blades to low pitch. Steel hubs use oil pressure to set low pitch and
counterweights to select high pitch.
A constant-speed prop operates in one of four conditions: fixed pitch (blades resting against the low-pitch
stops at rpm settings below where the prop governor can control the prop), on-speed, over-speed, or underspeed.
When on-speed, the prop is absorbing engine power at the exact rpm selected by the pilot. When under-speed,
the prop has too much pitch for the power being produced and the rpm is lower than that selected by the pilot.
(Under-speed can be compared to a car going up a hill - it slows down if additional power is not applied.) If in
the over-speed condition, the prop has insufficient pitch to absorb the engine power being produced and the
89
rpm goes above that selected by the pilot (like a car speeding as it goes down a hill).
The prop governor, produces the real magic in constant-speed props. It decides which of the three conditions
(the governor has no effect in the fixed-pitch condition) the prop is operating in and takes the appropriate
action. If the prop is in either the over-speed or under-speed condition, the governor automatically changes the
blade angle to provide more or less drag on the engine to maintain the rpm at the level selected by the pilot.
The prop governor uses a spring-and-flyweight mechanism to create this magic. Spring pressure is countered
by pressure generated by the flyweights, which rotate on a shaft geared directly to the engine. As the
flyweights' rpm increases, it takes a corresponding increase in spring pressure to balance the system.
When pilots adjust a constant-speed prop, they are increasing or decreasing the tension on this "speeder
spring." If spring pressure is greater than the flyweight force, the engine is turning too slowly and the underspeed condition exists. The governor then directs oil pressure to decrease prop blade angle and allow the
engine rpm to increase until the spring pressure and the flyweight force are equal at a new higher rpm.
If spring pressure is less than the flyweight force, the engine is turning too fast and is in the over-speed
condition. The governor then directs oil pressure to increase prop blade angle and reduce engine rpm until the
spring pressure and the flyweight force are equal at a new lower rpm.
Multi-Engine Magic
Props on multi-engine aircraft must be capable of feathering in the event of an engine failure. The feathering
feature drives the blades to a nearly 90-degree angle (blade chord nearly parallel to the slipstream) to eliminate
the significant drag created by a windmilling prop.
Most props feather the blades by using either a spring or air pressure inside the prop hub. If the engine fails,
there is no oil pressure for the prop governor to regulate. Since the blades feather virtually by themselves, there
are spring-loaded stop pins in the prop hubs of most aircraft to prevent the blades from feathering during
normal engine shutdown. Props must be feathered before a certain engine rpm, or these stop pins will engage
and prevent the prop from fully feathering.
Many multi-engine airplanes, especially those used for training that includes feathering a prop, employ an oil
accumulator to unfeather the prop after an engine shutdown. Repeatedly restarting an engine with a feathered
prop is hard on the engine and will shorten its service life significantly. An accumulator has an oil charge on
one side of a bladder and an air charge on the other. It gives pilots one shot of oil pressure to unfeather the
prop.
Some general aviation aircraft, such as turboprops and some seaplanes, use props that can reverse their pitch to
provide for negative (forward) thrust, which helps slow the aircraft after landing.
Constant-Speed Preflight
Carefully inspecting the prop during the preflight is important because props operate at very high forces, and a
slight defect may eventually lead to a catastrophic failure. Props experience two types of harmonic vibrations one caused by aerodynamic forces and the other caused by engine power pulsations.
These harmonic forces are concentrated in the last 12 inches or so of the prop blades, with the center of the
harmonic forces being approximately 6 inches in from each tip. Unfortunately, this area is where all the
damage from stones and runway debris occurs. Even a slight nick in the prop's leading edge can develop into a
crack that can lead to complete failure of the prop blade. The resulting imbalance could easily render the
aircraft uncontrollable in flight.
Also look for oil or grease leaks, loose blades or prop hardware, and proper safetying of all nuts and fittings
90
during your preflight. Be sure to inspect the prop spinner. Losing a spinner in flight is an experience better
avoided. Ensure that the spinner is tight, that there are no cracks, especially around the mounting screws, and
that there are no loose or missing screws. Do not assume that when you approach an aircraft with the spinner
missing, it is legal to fly. Most aircraft are not legal to fly with the prop spinner removed.
Constant-speed propellers make the most efficient use of engine power and provide optimum performance
during all phases of flight. If pilots take care of their props, the props will give them reliable, safe service.
By C. Hall "Skip" Jones
91
Recurrent Training - Cockpit Organization
Most pilots are aware of the fundamentals of planning a flight -- weather, weight and balance, fuel burn,
checkpoints -- but one often over-looked aspect of any flight is cockpit organization.
The Practical Test Standards (PTS) for all pilot certificates and ratings list cockpit organization as one of the
test areas. In airline operations, this subject has developed into a broad and comprehensive concept of cockpit
resource management -- CRM.
Even though CRM is generally applied in a two- or three-person cock-pit, the basic principles apply equally to
general aviation and single-pilot operations.
The major emphasis of cockpit organization, and of CRM, is being able to effectively use all available
resources to deal with routine and emergency situations. Obviously this would include making sure the
required charts or approach plates are not stowed in an unreachable location, and having the flight plan,
plotter, E6-B, pencils, and flashlight at hand and readily available. Although these items meet the requirement
and intent of cockpit organization as defined in the PTS, to really be proficient, we need to go another step -- a
step back.
Before we can properly organize our cockpit, we need to identify all the tools, information, and other resources
available to us. One of the most important resources we can arm ourselves with is time. In an emergency,
additional time will allow us to explore all options in resolving the emergency in the safest possible manner.
Pilots must be aware that time comes in several forms that we must identify and properly manage.
Our altitude above the ground is time. The higher we are, the more time we'll have to resolve problems. When
planning departures and arrivals, we must realize that at low altitudes we'll have little time to solve the
problem of a failed engine.
To make matters worse, flying at low speeds and at low altitudes increases our workload. This makes it even
more difficult to deal with an emergency. We must therefore plan for such possibilities before they arise by
having predetermined courses of action to follow should they occur. Since time isn't available at low altitude,
we must take time on the ground to develop the emergency action plans we'll follow on departure.
At cruising altitude we're in a position to take more time in troubleshooting problems before committing to an
off-field landing. Our workload is relatively low during cruise, and we can manage this resource to keep
ourselves way ahead of the airplane. It's a good time to gather weather information, check the status of our
aircraft and flight, review procedures or approach plates, and prepare for our arrival.
The usable fuel we have is another measure of time. Should we have a problem with our landing gear, for
example, extra fuel in the tanks will give us time to exhaust all possible means of gear extension before
committing to a gear-up landing. It may even give us the option of diverting to a more optimal location for a
gear-up landing (one with an on-site emergency crew). Extra fuel provides the opportunity to divert for other
rea-sons, such as low ceilings, poor visibility, strong or gusty winds, or poor runway conditions, such as snow
or potholes. (But we should know about this before takeoff.)
Time can also be measured by the capacity of our aircraft battery. Knowing its amp-hour rating will let us
make rational decisions regarding electrical load shedding in the event of an alternator failure.
If we have a 30-amp-hour battery, it will (if brand-new) support a 30-amp electrical load for one hour.
Conversely, it will support a 15-amp load for two hours or a 60-amp load for 30 minutes. We should review
the electrical system description in the pilot operating handbook (POH) and have an idea of the power
requirements of the various components.
92
Remember that anything which generates heat (landing lights, pitot heat) or mechanical motion (landing gear
and flap motors) uses a lot of power. Radio receivers use very little power and transmitters use a great deal
more. If the POH doesn't specify the electrical load for each item, look at the amperage rating of the breakers
or fuses that protect the equipment. If the POH doesn't pro-vide enough information, a knowledgeable
maintenance technician can usually help.
Finally, when planning cross-country flights, giving ourselves extra time in our overall travel schedule can
reduce "get-there-itis" and other psychological factors that might drive us to fly into bad weather or other
situations which would be better avoided.
The CRM concepts developed by the airlines make extensive use of all the crewmembers. General aviation
pilots often fly alone. Although we may not have another pilot on board, we can get valuable information and
assistance from people on the ground -- radar controllers, weather briefers, maintenance technicians, and other
pilots.
We should take the time to recheck weather along our route and at our destination and alternates. An early
diversion is sometimes the best plan if conditions are deteriorating. When flying VFR (visual flight rules), we
can still make use of the services provided by air route traffic control centers (ARTCC -- Center). By
requesting VFR radar advisories (flight follow-ing), we'll have an extra set of "eyes" to point out traffic.
In an emergency, controllers can help tremendously to reduce our work-load. More than a few times pilots
with mechanical or other problems have received assistance sorting out their difficulties from mechanics or
pilots both in the air and on the ground.
Radio frequencies for Flight Watch, approach, center, flight following, Flight Service Stations, and control
towers should be determined and recorded on a navigation log as part of the preflight planning process. In the
event of a problem, don't be bashful about asking for help.
If we're carrying non-pilot passengers, they, too, can be of great value. There's no reason why non-pilots can't
help with tuning radios, reading checklists, finding information in the POH or other publications, and watching
for traffic. This may add to our passenger's enjoyment of the flight and contribute to keep mutual safety.
Cockpit organization may sound like a simple matter of putting items in their proper place, but the concept is
really much broader and all-encompassing. If we take the time to identify all our resources and learn to
manage them wisely, we can enjoy a safer and more enjoyable flying experience.
Bob Rossier holds a single and multi-engine land ATP certificate, com-mercial single-engine seaplane certificate, and instrument and multi-engine instructor certificates. He's an active flight instructor and FAA accident
pre-vention counselor.
By Robert N. Rossier
93
Trial By Fire - Some lessons are better learned on the ground
Most pilots would agree that an engine failure is a major distraction. But if an engine quits, it's still possible to
keep flying the aircraft and maintain control. Almost all pilots would agree that an in-flight fire would be a
nightmare. After all, once you catch fire, it's really tough to concentrate on flying the airplane. Smoke can
make it impossible to see, or even breathe, and the intense heat from a fire can quickly destroy the physical
integrity of the airframe.
Personally, I'll take an engine failure over a fire any time, any place. Although training for this type of
emergency is required for any pilot certificate, many pilots don't pay much attention to the day-to-day potential
for fire. Considering the consequences, the subject deserves periodic contemplation and a thorough review of
proper emergency procedures. A short review from the accident files helps to illuminate some of the important
points.
CASE STUDIES
The Cessna 150 had just departed from the Groton (Conn.) Municipal Airport on a pleasure flight. Shortly
after departure the pilot noted white smoke, indicative of an electrical fire, in the cockpit. He turned off the
master switch and returned for an immediate landing. Investigation determined that the starter had not
disengaged after starting. The starter, turning at high speed during takeoff and climb, was operating like a
generator. The excessive current overloaded the electrical system, resulting in an electrical fire. This aircraft
was not equipped with an overvoltage warning light.
Fire requires three elements: fuel, air, and heat. Put these three in the proper juxtaposition - into a "fire
triangle" - and a fire will ensue. Remove one from the picture, and the fire will soon die. In this case, the
insulation on the wiring was the fuel, the excessive current generated the heat, and the air, the oxidizer, was
already there (as it always is). Fortunately, the pilot recognized the problem and took immediate action.
There are two basic types of in-flight fires: electrical and fuel/engine fires. Electrical fires are generally
distinguished by the appearance of a white smoke caused by the smoldering and burning of the plastic
insulation on the wires. They also have a distinctive odor. Fuel and engine fires can be potentially more
dangerous and can also be more difficult to detect and identify, as the following case suggests.
The pilot and instructor departed from Jefferson County Airport, Broomfield, Colo., just around dusk on a
routine training flight in a Piper Turbo Arrow (PA-28R-201T). Approximately 5 minutes into the flight, the
instructor noticed a low fuel pressure indication, followed by surging of the engine. He determined that the
engine ran best on the "low boost" setting.
While returning to Jefferson County Airport for an emergency landing, the cockpit began to fill with the thick,
white smoke that's indicative of an electrical fire. They killed the master switch and discharged the fire
extinguisher. The engine quit on final approach and the instructor glided the aircraft to a safe landing on the
runway.
After the duo escaped safely and the fire was extinguished, an investigation determined that the fuel line to the
distribution spider had separated at a fitting, allowing fuel to spray into the engine compartment. The fuel was
ignited by the heat from the turbocharger, and air blasting into the cowling intensified the fire.
In this case we learn that things are not always as they seem. It's interesting to note the indications of trouble,
the pilot's actions, and the true cause of the problem. The instructor followed the checklist and activated the
auxiliary fuel pump at the indication of low fuel pressure and engine roughness.
This did two things, one of which the pilot didn't expect. While the aux pump pushed enough fuel through the
separated connection to keep the engine running (usually a primary consideration of the pilot of a single-
94
engine aircraft), it also sprayed fuel into the engine compartment, which resulted in a fire.
The white smoke in the cockpit was not from an electrical fire, but emanated from the burning defroster hoses
located near the turbocharger, just ahead of the fire wall under the cowling. While shutting off the master in
response to an electrical fire is the correct action, in this case it caused a couple of things the pilot wasn't
expecting.
Shutting off the electrical power also killed the auxiliary fuel pump, which stopped fuel flow to the fire under
the cowling, causing it to be extinguished by the time they landed. But without the extra fuel pressure from the
aux pump, the engine wasn't getting enough gas - thus the engine failure on short final.
Because it's not always possible to determine the precise cause of a problem, the best you can do is follow the
proper procedures and checklists, and keep your priorities straight at all times. One of these priorities is getting
the aircraft quickly back to the ground, as this next example illustrates.
The pilot and passenger departed from El Paso, Texas, on a night check delivery run in a Twin Commander.
Shortly thereafter, the pilot noted erratic fuel pressure readings, followed by an excessive fuel flow. Flames
emerged from the right engine, which the pilot promptly secured.
The pilot saw the runway lights of a private airstrip during his emergency descent. He landed there safely, and
he and his passenger extinguished the fire, after which the right wing separated from the engine nacelle. An
incident investigation determined that the fuel system failure and subsequent engine fire were caused by
improper maintenance.
The lesson of this example is the importance of getting the aircraft on the ground quickly. Obviously the fire
caused rapid structural weakening of the wing. Had the wing separated in flight, it would no doubt have been a
fatal accident. If you have an engine fire, get the aircraft on the ground IMMEDIATELY.
DEALING WITH A FIRE
While both electrical and engine fires are bad, you deal with them differently. With an electrical fire, the first
action the checklist calls for is turning off the master switch. This removes the "ignition" or "heat" arm of the
fire triangle. But beware! Even though you've cut off the source of heat, the wiring and components are still
hot and can continue to smolder for some time.
Electrical fires generally occur behind the instrument panel, where there is the greatest accumulation of wires.
Therefore, the next step is generally closing cabin vents to reduce the amount of air that can feed the fire.
While this may seem contrary - you may wish to clear the air and breathe - remember that a raging fire, fed by
an oxygen-rich flow of fresh air, will shortly incapacitate you. What you need to do is isolate the cabin so that
the fire extinguisher, if you have one and intend to use it, will be more effective. Once the fire is out, it's OK to
ventilate the cabin. It should go without saying that a precautionary landing should be made.
Dealing with in-flight engine fires can be infinitely more exciting than electrical fires. Consider this: With
evidence of an engine fire - black smoke or flames billowing from the cowling or bubbling paint on the
cowling - most checklists say to shut down the engine (even if you only have one engine).
The primary reason for this is to stop fuel flow to the fire, which will, one hopes, extinguish it. This action
does guarantee a forced landing. Some checklists and amplified procedures sections of aircraft manuals also
suggest diving the aircraft at relatively high speed to effectively blow out the fire.
While these suggested actions - kill the engine and dive for the ground - sound contrary to self-preservation,
remember your priorities; Extinguish the fire and land quickly. This is your only hope for survival. Shut her
down and head for the ground.
95
When it comes to extinguishing a fire, it's important to have the right tool for the job. Although not required by
regulation, for non-revenue flights it's a good idea to carry a fire extinguisher with you on each flight.
Much has been written about selecting an aircraft fire-extinguishing agent. The general consensus is that Halon
is best because it doesn't cause instant instrument conditions in the cockpit after it's been discharged. Halon is
also kinder to delicate instruments and electronics, and, in the concentrations and exposures necessary to fight
a cockpit fire, it doesn't incapacitate the people in the cockpit.
This isn't to say that the other extinguishers (carbon dioxide and dry chemical) are not valuable. Considering
the greater incidence of fires on the ground, such as during engine start and after a forced landing, these other
extinguishers are certainly worth having around. But if you're choosing one to carry in your flight bag, Halon
is the way to go.
PREVENTION
It would be nice to be able to prevent all fires. While this may be possible in theory, in practice it's impossible.
But a thorough knowledge of your aircraft's systems, combined with a careful preflight and operational
awareness, can help.
Look for fuel stains, leaking gascolators and fuel lines, loose oil dipsticks, and oil leaks during your preflight
inspection. Bird nests and oily rags in the cowling are also excellent sources of fires. Beware of any fuel odors,
either in the cockpit, engine compartment, or near the fuel tanks. If you find something that's not quite right,
get it checked out before flying.
When starting the engine, especially during cold weather, be sure to follow recommended procedures to avoid
over-priming and other conditions conducive to fires.
Inflight, pay attention to engine and electrical system instruments. High temperatures can mean something is
amiss. Excessive fuel flow or erratic fuel pressure can be the first signs of a fuel leak. And watch the ammeter
and over-voltage lights. If a circuit breaker pops, exercise extreme caution. Reset it once. If it pops again,
leave it, or you'll defeat its purpose.
There's probably nothing worse than in-flight fires. Although pilots might not be able to avoid them, a little
extra attention can help prevent them. And thorough training and practice of emergency skills and procedures
might make the difference between disaster and success if the situation actually arises.
Bob Rossier holds a single and multi-engine land ATP certificate, commercial single-engine seaplane
certificate, and instrument and multi-engine instructor certificates. He's an active flight instructor and an FAA
accident prevention counselor.
By Robert N. Rossier
96
Flying Smart - Letdown Chart
As a student working the cross-country problems of aircraft performance, I had
questions. It was clear that most pilot operating handbooks (POHs) had time-anddistance-to-climb and range-and-endurance charts, but planning the descent from
cruise really puzzled me.
As a student, getting down from 4,000 feet above ground level (AGL) usually wasn't
a problem. It was a problem when I started flying airplanes with increased
performance. Now, as a multi-engine instructor flying heavier airplanes higher, when
to start down is a question my students regularly ask.
In consideration of passenger comfort and engine shock cooling, I recommend a standard descent rate of 500
feet per minute (fpm). Determining when to start the descent results in some airborne number crunching of
altitude, ground speed, and distance. To avoid distracting in-flight mathematics, I devised a letdown data chart
that's quick and easy to use.
The chart is based on a 500-fpm descent rate. To use it, find the altitude you need to lose in the left-hand
column. Then find your ground speed in the top row. Where the two intersect is the distance from your
destination at which you should start your cruise descent.
If you need to lose 6,000 feet and your ground speed is 110 knots, you'd start your cruise descent 22 miles out.
To extend the chart beyond the speed and altitude shown here, the formula is [altitude to lose] times [ground
speed] divided by [30,000 (60 seconds time 500 fpm)].
Remember, when descending under visual flight rules, you should be at traffic pattern altitude when you reach
the airport. Under instrument flight rules, your destination is the appropriate initial approach fix and altitude.
GS
By William Salvaggio
Start Down Distance Chart
90 100 110 120 130 140 150 160 170 180 190
ALT
3000
9
10
11
12
13
14
15
16
17
18
19
4000
12
13
15
16
17
19
20
21
23
24
25
5000
15
17
18
20
22
23
25
27
28
30
32
6000
18
20
22
24
26
28
30
32
34
36
38
7000
21
23
26
28
30
33
35
37
40
42
44
8000
24
27
28
32
35
37
40
43
45
48
51
9000
27
30
33
36
39
42
45
48
51
54
57
10,000
30
33
37
40
43
47
50
53
57
60
63
11,000
33
37
40
44
48
51
55
59
62
66
70
12,000
36
40
44
48
52
56
60
64
68
72
76
13,000
39
43
48
52
56
61
65
69
74
78
82
14,000
42
47
51
56
61
65
70
75
79
84
89
15,000
45
50
55
60
65
70
75
80
85
90
95
97
Recurrent Training - Ice, Snow and Frost
It was a calm day in early December, 9,000 scattered and visibility 10, when the pilot and two passengers
departed from Fort Collins, Colo., in a Grumman AA-5B Tiger. According to the pilot, the aircraft used more
than twice the normal runway for takeoff.
Soon after takeoff, the stall warning horn sounded continuously and the pilot could no longer maintain altitude.
The aircraft struck a road sign .5 miles from the runway as the pilot attempted a forced landing on a highway
median. The Grumman finally came to rest on a highway exit.
The accident investigator noted that the entire surface of the wings and horizontal stabilizer were covered with
rough ice. According to the National Transportation Safety Board (NTSB) report, the 1,100-hour pilot said the
ice on the surface of the airfoils had no bearing on the accident. For most pilots, the sight of ice on the wings
sends shivers down their spines. Somehow, this unfortunate pilot had missed the cue.
With the onset of winter, pilots are reminded of the need to clean the wings and control surfaces of any
accumulations of ice and snow because they can dramatically alter the airfoil and affect the ability to develop
lift. Even something as seemingly innocuous as frost will spoil aerodynamic lift as sure as a thick coating of
rough ice. Particularly on cold evenings, frost can form quickly, and disaster can strike suddenly.
It was a clear night when the pilot of a Mooney M20C and his three passengers prepared for departure from St.
Marys, Pa. The pilot wanted to have the aircraft deiced, but the driver of the fuel truck told him the airport had
no deicing fluid. Using credit cards and paper towels, the pilot and passengers tried to remove the frost.
According to one witness, the frost reformed on the wings as quickly as they scraped it off.
The pilot attempted to take off just after 9 p.m. A witness said the takeoff roll was very long. Shortly after
takeoff, the aircraft entered a steep bank and descent. It crashed into the trees near the airport and burst into
flames. All aboard were killed.
FLIGHT CONTROL PROBLEMS
Ice, snow, and frost don't just affect the ability of airfoils to generate lift. The additional weight can unbalance
control surfaces, which leads to a dangerous aerodynamic condition called flutter. Such was probably the case
in the following accident.
A lone pilot on a personal flight to Columbia, Tenn., took off from Nashville in his Cessna 206 at
approximately 4:20 p.m. on a February afternoon. According to a line worker, the pilot took off with a halfinch of solid ice on the top surfaces of the wings.
The pilot experienced a severe vibration that shook the entire aircraft soon after departure. He reduced power
and the vibration subsided. Then he noticed an aileron control problem and saw that the left wing tip was
moving up and down. Fearing imminent disaster, he made an emergency landing in a nearby field.
An investigation of the aircraft found that both ailerons had traveled beyond their limits and were bent, and the
left wing main structure was fractured. Fortunately, it had held together long enough to get the pilot safely on
the ground.
Although there are no specific regulations in Federal Aviation Regulation (FAR) Part 91 regarding aircraft
operation with ice, snow, or frost on the aircraft, FAR Part 135, which regulates air taxi and commercial
operators, does provide specific guidance that pilots operating under Part 91 should consider.
FAR 135.227, Icing Conditions: Operating Limitations, says pilots are not allowed to take off with frost, snow,
or ice on any propeller, windshield, powerplant installation, or adhering to an airspeed, altimeter, rate of climb,
98
or flight attitude system. This regulation also prohibits takeoffs with snow or ice on the wings, stabilizers, or
control surfaces. It further states that any frost adhering to the wings, stabilizers, or control surfaces must be
polished smooth. The above accident reports seem to emphasize the wisdom of this regulation.
Cold weather can cause the formation of ice on other aircraft surfaces as well. Water and slush can freeze on
brakes and landing gear, and ice crystals can form in the fuel. In the following accident, ice formation inside
the aircraft led to a severe control problem.
The pilot of a Lake amphibian departed Avon, N.Y., on a clear day in late March. During the preflight, he
noted that the elevator would not move, but it seemed to function normally after the pilot applied some
external heat. Somewhere enroute to Swanton, Vt., the pilot found that he was again unable to move the
elevator. Fortunately, the elevator trim control was functional, and he was able to control the aircraft.
On final approach, the aircraft caught a gust of wind and the nose pitched down. The pilot was unable to regain
control and the Lake crashed short of the runway. When the investigator examined the wreckage, he found that
solid ice had formed in the hull, encasing the elevator control push-pull rod, making it immovable. The aircraft
was destroyed in the crash, and the pilot was seriously injured.
This type of problem is not as uncommon as you might think. The pilot of the Lake amphibian probably
figured that after the heating during preflight, the control problem was solved. But remember that unless all the
water and moisture is removed in the process, the problem can recur as soon as the aircraft is operated again in
freezing temperatures.
ENROUTE ICING PROBLEMS
Ice, snow, and frost are not just a problem to be considered during preflight inspections. Pilots are required to
operate aircraft only in the conditions for which the aircraft is certificated. And even if an aircraft is approved
for flight in known icing conditions, it's generally a good idea to avoid such situations.
There are several excellent reasons to avoid flight in icing conditions. Ice can form on the pitot tube and static
vent, rendering the airspeed indicator, altimeter, and vertical speed indicator (VSI) inoperative. It can build up
on antennas, distort radio signals, and result in loss of navigational and communication capabilities.
When ice accumulates on the wings, it alters the shape of the airfoil, reduces the amount of lift produced, and
increases the stall speed. Combine this with the increased weight of the aircraft and the reduced efficiency of
an ice-covered propeller, and an aircraft can quickly become a block of ice hurtling toward the ground.
Even when operating aircraft equipped with deice or anti-ice equipment, pilots must understand the limitations
of the equipment. Most systems only remove ice from specific, critical locations, such as the leading edges of
the wings, windshield, and propellers. That leaves plenty of airframe and appendages, including the vertical
and horizontal stabilizers, upon which ice can form. Although deice boots may remove ice from the leading
edges, ice can still accumulate on other portions of the wing. This can be a problem, particularly during
departure and approach phases of flight, when the aircraft is operating at a low airspeed and a high angle of
attack.
Take, for example, the Cessna 310 making an ASR (airport surveillance radar) instrument approach into
Lubbock, Texas, one foggy December afternoon. The ceiling was partially obscured, 400 feet broken, and the
pilot was flying from the right seat. His passenger, a rated private pilot, was in the left seat.
The twin-engine Cessna began accumulating ice during the approach, and the pilot activated the deicing
equipment several times, removing ice from the wing leading edges and props. The aircraft broke out of the
clouds at 400 feet and, due to the heavy ice accumulation, continued a high rate of descent.
As is typical with many deicing systems, only the left side of the windshield had a window heater, so the
99
pilot's visibility through the right windshield was restricted during the final approach. The pilot made a hard
landing, lost directional control, and crashed into a concrete wall. Fortunately, neither the pilot nor the
passenger were injured.
According to the Airman's Information Manual, the most severe in-flight structural icing conditions occur
when it's 0?C and colder. Although it can occur in clear skies, icing is most prevalent in conditions of visible
moisture, such as in clouds.
A thorough evaluation of cloud bases and tops along with temperatures aloft can be an important preflight
consideration. But remember that multiple icing levels are possible, and even if you can safely fly above icing
conditions, you may be required to make an approach through them. The consequences of even a short
exposure to icing conditions can be disastrous, to say nothing of what could accumulate during a lengthy hold
or a missed approach procedure.
All clouds at subfreezing temperatures have the potential for ice formation, but the type of ice formed depends
on several factors, including water droplet size and distribution, and the aerodynamic effects of the aircraft.
There are no hard-and-fast rules that determine whether ice will or will not form in specific conditions.
Ice comes basically in three varieties: rime ice, clear ice, and a mixture of the two. Rime ice is brittle and frostlike. It usually forms in conditions where the droplet sizes are small, such as in stratus clouds and light drizzle.
Air is trapped within the ice as it forms, giving it a white or milky appearance. It primarily accumulates on
wing leading edges and the front of anything projecting into the airstream, such as landing gear, antennas, and
horizontal and vertical stabilizers. Its rough shape is particularly effective in reducing aerodynamic efficiency,
but due to its brittle nature, it is more easily removed than clear ice.
Clear ice forms when water droplets spread out on the surface before freezing. The result is a clear, hard ice
that adheres to all areas of the airframe and is very difficult to remove. It generally forms in rain and
cumuliform clouds, and it can accumulate quite rapidly.
If icing conditions are encountered in flight, take action immediately. A 180-degree turn, climb, descent, or
some combination of these maneuvers is recommended. If you're flying under instrument flight rules (IFR),
don't let ATC push you into continuing on or waiting before taking evasive action. If necessary, declare an
emergency and do what you must to get out of the ice. Icing can build tremendously fast, disabling aircraft in
minutes, or in some cases, just seconds.
COMPOUNDING THE ERRORS
The pilot of a Piper Saratoga took off IFR with two passengers from Lima, Ohio, one dark night in February.
Visibility was 4 miles in fog, the ceiling was 800 feet broken, and a heavy wet snow was falling. The pilot said
he cleared the snow off the wings, but not off the top of the T-tail.
Slush from the runway was thrown up and over the aircraft during the takeoff roll, but he continued and
climbed to 1,100 feet mean sea level (MSL). At this point, the airspeed decayed to about 60 knots and the
landing gear automatically extended. The pilot maintained control of the aircraft by instrument references and
crashed in a nearby field. Miraculously, nobody was injured.
Winter flying poses a number of hazards to pilots, and the problems of ice, snow, and frost are just the tip of
the proverbial iceberg. But with proper training, knowledge, and judgment, pilots can avoid the perils and
pitfalls and effectively deal with the demons of winter.
Bob Rossier holds a single and multi-engine land ATP certificate, commercial single-engine seaplane
certificate, and instrument and multi-engine instructor certificates. He's an active flight instructor and an FAA
accident prevention counselor.
100
For more information
For more information on the subject of icing and operations in cold environments, refer to the following:
Advisory Circular 91-51
Airplane De-Ice and Anti-Ice Systems
Advisory Circular 91-13C
Cold Weather
Operation of Aircraft
Advisory Circular AC 00-6A
Aviation Weather, Chapter 10: Icing
Accident Prevention Pamphlet FAA P 8740-24
Tips on Winter Flying
By Robert N. Rossier
101
Form And Function - Hidden Wheels
Increased speed has always been a goal of aircraft development. One of the impediments to achieving this goal
has been the parasite drag created by nonretractable landing gear. The solution is to retract the gear to hide the
wheels from the slipstream once they have served their purpose.
There are several significant advantages to retractable landing gear: It reduces parasite drag and allows increased speed without increasing engine power. Retractable gear also improves aircraft performance in critical
flight areas such as climb angles and rates, engine-out glide ratios, and single-engine operations of multiengine aircraft.
Another factor, intangible but real, is a pilot's ego. Many pilots believe that flying more sophisticated aircraft
demonstrates greater flying skills and abilities. Valid or not, ego drives some pilots toward high-performance
aircraft when simpler aircraft would do the job just as well.
Retractable landing gear systems are not without drawbacks. They are heavier than fixed-gear, which reduces
the aircraft's useful load. They require more maintenance because they have more moving parts. Retractable
landing gear systems are susceptible to two types of problems - mechanical and human. Everything else being
equal, mechanical systems with more moving parts fail more often than those with fewer moving parts.
The human factor is not a problem with fixed-gear systems - you can't forget to lower the gear. If pilots flying
retractable-gear airplanes used their checklists religiously, there would never be another pilot-induced gear-up
landing, only those caused by mechanical failure. Accident and incident statistics demonstrate that pilots must
focus on their performance and not the landing gear's reliability.
Increased insurance costs are another drawback to retractable landing gear. If you don't believe this, call an
aviation insurance company and get a hull-coverage quote for a Cessna 172 and a Cessna 172RG. Retractable
gear also requires additional training. Physically operating the gear is straightforward, but adjusting the pilot's
attitude and thought processes for flying a high-performance aircraft takes time and is often ignored in
transition training.
Different Retractions
There are a number of different power sources for retracting the landing gear: Mechanical, engine-driven hydraulic, electric-driven hydraulic, and electric systems are the most commonly used in general aviation.
Mechanical gear systems have a control connected directly to the retraction mechanism. The pilot manually
operates this control to retract and extend the gear. Most mechanical systems have roller chains and sprockets
connected to a hand lever or a jack screw. This system is reliable, lightweight, and easy to maintain and
inspect. It is, however, limited to smaller aircraft with relatively lightweight gear systems and low gearoperating speeds.
Engine-driven hydraulic systems are commonly seen on multi-engine aircraft such as the Piper Apache and
Aztec. They have pumps on one or both engines that power the hydraulic system that retracts and extends the
landing gear and associated doors.
Engine-driven hydraulic systems provide reliable high-pressure hydraulic power if the engine is running. If the
engine (or engines) with the pump fails, pilots must use the manually operated emergency hydraulic pump to
raise and lower the gear. Some aircraft use pressurized nitrogen to extend the gear as a one-time emergency
extension option in the event of a complete hydraulic system failure.
Electric-driven hydraulic systems eliminate the need for an engine-driven hydraulic pump. They also eliminate
the possibility of an engine failure interrupting hydraulic power to the gear system. The Piper Arrow uses an
electric-hydraulic system. An electric motor powers the pump that provides hydraulic pressure to the system,
which retracts the gear and holds it in the retracted position, trapping fluid in the hydraulic cylinders. The
emergency extension system is a valve that releases the trapped hydraulic pressure and lets the gear free-fall to
102
the down position.
A sensor that measures differential air pressure automatically extends the gear when the Arrow slows below a
preset airspeed. Pilots can deactivate this automatic extension system so the aircraft can be flown at low
speeds, such as for slow flight and stall-awareness training, without having to deal with unexpected gear
extension.
An electric-powered gear system uses an electric motor to extend and retract the landing gear mechanically.
The Mooney MSE (201) uses this system, and its required backup system consists of a pull cable. When
activated, the pull cable disconnects the gear system from the motor and lets the pilot extend the gear
manually. Pulling the cable, which is similar to a lawnmower starting cord, ratchets the gear into position in
12-20 pulls.
Retractable-gear systems often include doors that cover the wheel wells to reduce drag further. Some doors are
attached to the landing-gear legs and go where the gear goes. Other aircraft have electrically, hydraulically, or
mechanically operated doors that open or close in a sequence independent of the gear. The Cessna 210 series
has sequentially operated hydraulic gear doors. When the pilot raises the gear after takeoff, the system opens
the gear doors before retracting the landing gear.
Position Indicators
All retractable-gear aircraft must have landing gear position indicators within easy view of the pilot. They are
generally located next to or near the gear switch. Three green lights - one for each wheel - are the most
common indicators. If all three wheels are down and locked, all three green lights will glow. If one of the
wheels is not down and locked, the representative light will not light up, or will be red, depending on the
aircraft. Some aircraft have a separate red light that indicates an unsafe gear extension.
If the gear is in transit - going up or down - the three lights will not illuminate, or will glow yellow or red. If
the wheels are all up and locked, the lights will all be out. Some older aircraft have an in-transit light that
glows when the wheels are changing position and a red light that shines constantly when the gear is up. Other
older aircraft have mechanical gear indicators. The most common is a three-window indicator that uses
different color "flags" to indicate up or down.
Micro switches control the gear position lights. They are located at various points in the gear system to open
and close the appropriate circuits to the lights when the gear is down and locked, in transit, or up and locked.
Federal Aviation Regulations require aircraft with retractable landing gear to have a system that warns pilots to
extend the gear before landing. These systems work in various ways. A throttle-position system is the most
common. A micro switch is attached to the throttle. If the pilot retards the throttle past a preset point (as would
occur on final approach) and has not extended the gear, a warning horn will sound.
Aircraft with retractable landing gear also have a safety switch that prevents gear retraction on the ground. The
squat switch is the most common type. Generally located on a main-gear shock strut, the squat switch
deactivates the cockpit gear switch when the strut is compressed (as it would be on the ground). When the strut
extends after takeoff (because it has no weight on it), the squat switch is no longer activated, and the gear can
be retracted.
Do not move the gear selector to UP on the ground and depend on the squat switch to keep the wheels down
and locked. Hitting a dip in the runway on the takeoff roll, or another circumstance that decreases the weight
on the main gear, may be enough to deactivate the squat switch and start the gear retraction cycle.
The squat switch is located on the nosewheel strut on aircraft, such as Cessna singles, that do not have maingear shocks. While the switch works the same, pilots must pay attention, because the gear retraction system
becomes active when the nose gear is raised. The Cessna retraction system will not raise the main gear with
103
the aircraft's weight on it, but the nose gear will retract. The main gear will begin to retract when the wings
start to carry the aircraft's weight. If the aircraft settles back down for some reason, the gear may be in transit
or have retracted. Neither condition will lead to a positive aeronautical experience.
Retractable-gear aircraft have two airspeed limitations that do not apply to fixed-gear aircraft. Vle is the
maximum airspeed at which the aircraft can be flown with the landing gear extended. Vlo is the maximum
speed at which the landing gear can be extended or retracted. Vlo usually equals or is lower than Vle because
of airspeed restrictions on the gear doors in transit.
Preflight Precautions
Inspecting retractable landing gear before flight is similar to preflighting fixed landing gear. Oil leaks of any
kind from any location on the gear system should be a grounding item and should be referred to your
maintenance technician for repair. Excessive or uneven tire wear is a sign of gear problems. Check for proper
oleo strut height. If low, have maintenance correct it. Operating the aircraft with low struts will eventually
damage the internal system. Check for security and safety wiring of all exposed hardware, fittings, springs,
cables, and torque links. Finally, check for abnormal main-gear vibration and nosewheel shimmy during taxi
and take-off and landing rolls.
Retractable landing gear improves aircraft speed and performance. With proper maintenance, and pilot
attention to preflight inspections and in-flight checklists, it will provide hours of smooth takeoffs and landings.
By C. Hall "Skip" Jones
104
Instrument Training - Checklists
"I've never made a mistake in my life. I thought I did once, but I was wrong." That quote appeared in an old
Peanuts comic strip.
As humans, we're all susceptible to mistakes, mistakes that pilots avoid by using checklists, VFR and
particularly when flying instruments. The proper use of checklists is a controversial subject, and I'm going to
fan the flames with my observations gained during 33 years (and counting) of flying.
There are three forms of checklists: flow patterns, mental checklists, and written checklists. To prevent errors,
at least two checklists must be used for every critical event. Pilots who rely on only one checklist make
mistakes, a fact that I have personally observed on too many occasions.
Flow patterns, the precursor to mental and written checklists, should be highly stressed in any training
program. The most common flow pattern is the preflight inspection. Students are taught to start at a certain
point and then return to that point after circling the airplane and checking every nook and cranny. Then, in the
cockpit, they review the written "preflight checklist" in order to check their performance.
The next flow pattern occurs prior to engine start. I start between the front seats and move forward along the
floor and then up to the instrument panel, at which point I move horizontally from sidewall to sidewall as I
cover each item, setting the appropriate ones for engine start. Finally, when ready to start the engine, I review
the written "Before Start Checklist."
To prepare for takeoff, the same flow pattern is again used when clear of congested areas and taxiing toward
the run-up area. When finished, I use the CIGARS mental checklist: Controls, Instruments, Gas, Attitude
Trim, Run-up and Radios, and Seatbelts. Finally, I review the written "Before Takeoff Checklist" to audit my
performance.
To prepare for landing, I use the same process. The flow pattern is followed by the GUMPS mental checklist:
Gas, Undercarriage (landing gear), Mixture, Prop, Seatbelts, and the written "Before Landing Checklist."
Use flow patterns and mental checklists to prepare the airplane for the next event, and use the written checklist
to inventory your performance.
The written checklist should be used as a "done list," not a "do list," and here's where controversy exists. Some
individuals say that written checklists must be used in a "check and respond" manner. That's true for a twopilot crew and low-time student pilots, but for advanced single-pilot operations, such usage is subject to gross
errors, such as completely missing specific items due to interruptions. Yes, it takes additional time to run the
combination of flow pattern, mental checklist, and written checklist, but the result is nearly bullet-proof, and
the flight's safety is maximized.
The habitual use of flow patterns makes emergencies easier to cope with. When something goes wrong, it's
critical that the pilot sit on his hands for a few moments and put his mind in gear. Familiarity with flow
patterns permits a quick assessment of airplane status and a rational decision regarding movement of controls
or switches.
Mental checklists are of utmost importance during instrument flight because many events do not have a written
checklist. And I think it's fair to say that none of us want the gross weight of the paperwork to equal the gross
weight of the airplane. Here are the mental checklists that I teach.
Lights, Camera, Action
The runway and cruise altitude mental checklist. Flying is like being in the movies because the FAA is
always watching us, so Lights, Camera, Action is appropriate. Use this checklist when entering or exiting the
105
runway and when reaching or leaving cruise altitude. Lights refer to the strobe and landing lights, camera
refers to the transponder, and action refers to all other essential elements: power output during takeoff, flaps,
cowl flaps, carburetor heat, mixture, fuel pumps, etc.
ANEWS
The en route mental checklist: Airplane, Navigate, Emergencies, Weather, and Systems. Fly the airplane,
confirm navigation requirements, think about possible emergencies, monitor destination and alternate weather,
and monitor aircraft system.
Five-Ts
The fix-crossing mental checklist: Time, Turn, Throttle, Tune, and Talk. Some pilots will argue about the
sequence or name of these five events, but believe me, that sequence was chiseled in stone years ago.
Time is first because pilot work load is low when waiting for station passage, an ideal time to include the
clock in your scan. At station passage, it takes less than a second to start the stopwatch or make a mental note
of the time.
Turn, throttle, tune, and talk is a sequence that follows an unbendable aviation axiom: aviate, navigate, and
communicate.
1. Turn and throttle: Aviate - fly the airplane (turn and/or descend).
2. Tune: Navigate - prepare the navigation radios for course guidance (VOR, OBS, ADF radio compass
card, or the No. 2 VOR or ADF for the next step-down fix's cross-bearing).
3. Talk: Communicate - ATC report if required.
It's always disheartening to see a pilot who crosses a fix and immediately picks up the mike to make an ATC
report. That's called "picking up the mike and dropping the airplane." When ATC instructions are received, an
immediate acknowledgment is required from the pilot, but when a pilot-initiated ATC report is required, do so
only after the airplane has been pointed in the right direction and the navigation radios have been set up for the
next requirement.
Big-7
The instrument approach mental checklist. Seven prerequisites for a safe instrument approach:
1. Approach descent checklist for your airplane: fuel selector, boost pump, altimeter setting, DG
aligned with the magnetic compass (same for HSI, and check the gyro slaving indicator), seatbelts
fastened, loose items stowed, and all approach charts for the destination airport readily available.
2. ATIS received and radios set for the approach. One VOR receiver, the ADF, and the marker beacon
audio can usually be set in advance. Before setting up a VOR receiver, look at your approach chart to
determine the sequence for using the VOR receivers. Usually No. 1 will be used for final approach,
No. 2 before that, No. 1 before that, etc. If the VOR receiver you're currently using for course
guidance is out of sequence, swap receivers now in order to minimize your work load later during the
approach. If you always use your No. 1 receiver for course guidance, your work load could be higher
than necessary. If flying an NDB approach, be certain to monitor the audio identifier during the entire
approach, and make triple certain that the antenna switch is in the ADF position. If using DME, back
up the first one or two fixes with published cross-bearings to verify DME accuracy. Making descents
based on single-source navigation information is extremely dangerous.
3. Notes that can kill you. Review the approach chart for terrain and obstructions, circling approach
restrictions, and navigation equipment requirements.
4. The missed approach procedure. Review the entire procedure, and memorize the first steps, the
steps required while the airplane is being transitioned into the climb and reconfigured for the missed
approach. An example would be, "If I miss, it's straight-out to 1,200 feet and then a climbing left
turn." The published missed approach would have further instructions that can be referred to after the
climb has been established. Then, and only then, make the ATC missed approach report. If ATC calls
you while you're transitioning into the climb or while you're getting the missed approach set up on the
navigation receivers, ignore the call until your work load is under control. Never violate the aviate,
navigate, and communicate axiom. If you're a new instrument pilot, do not be intimidated by ATC,
106
you're pilot-in-command, you have the final responsibility for the flight.
5. The MDA or DH. If the MDA is 1,735 feet, remember 1,800 feet. I've never understood the reason
for this, but if most pilots (myself included) try to remember 1,735 feet, they'll continually look back
at the approach chart to make sure they're right. If they remember 1,800 feet, they spend more time
looking at the instruments (a great idea when close to the ground), and approaching 1,800 feet they'll
always remember that they're good for 1,735 feet.
6. Time to the MAP. As with the preceding example of remembering altitude, do the same thing with
time. If your computed time is 1:43, think 1:30. At 1:30 you'll always remember that you can go for
another 10 or so seconds.
7. Aircraft speed. The last step is the speed reduction to slow cruise, an action that depends on how
comfortable you are flying the approach. Some pilots will slow down earlier than others, and that's to
be expected. To be rushed on an approach is an invitation for error.
The Big-7 checklist is a segmented checklist (it cannot be completed at one time) that begins just prior to
leaving cruise altitude and that ends just prior to starting the approach. Other nice-to-know items could be
added to this checklist, but that would defeat its purpose: checking the mandatory items that are required for a
safe approach. At first, students will spend considerable time accomplishing this checklist, but with practice it
becomes easy to execute.
An alarm should go off in every instrument pilot's mind, chills should run up their back, and their hands should
get clammy if the Big-7 checklist has not been completed prior to starting an instrument approach. Commit
this checklist to memory, complete one step at a time, stay relaxed, and continually run your mind's conveyor
belt.
I use the term conveyor belt to remind students that when flying there are certain pieces of information that
must continually run through one's mind. Three items pertain to any VFR or IFR flight: position, wind
direction and velocity, and planned emergency action if the engine quits. Three additional items pertain to any
IFR flight: the next heading, the next altitude, and the next course. And three more items pertain to any IFR
approach: DH or MDA, time inbound, and the initial missed approach procedure, three elements of the Big-7
checklist. This seldom-mentioned review process and the nine items that I've listed illustrate why the
instrument approach is the most complex segment of instrument flying.
Can't Do It Very Fast Virginia (VICTOR For The Ladies)
The multi-engine mental checklist. Control the airplane (attitude and power), Drag elimination (gear, wing
flaps, cowl flaps), Identify the dead engine (dead foot, dead engine), Verify the dead engine (throttle to idle),
Feather (prop control and mixture), and Visually check engine (fire).
When pilots are introduced to flow patterns and mental checklists, their enthusiasm often makes them
erroneously assume that written checklists are unnecessary. Please don't make that mistake. Written checklists,
our final safety check, our backup system, must always be used.
By Ralph L. Butcher
107
Ounce of Prevention Suddenly Single - Beyond "dead foot, dead engine"
BY THOMAS A. HORNE (From AOPA Pilot, August 2001.)
From our first days as student pilots of small single-engine trainers we yearn to fly twins. The allure of
multiengine flying is compelling, what with the promise of extra power, more speed, better climb rates,
systems redundancies, and — well, let's face it, ramp and sex appeal. But while twin-engine flying definitely
has its advantages, it has a dark side, too. It demands extra care on the pilot's part, and learning a whole new
set of planning and procedural skills. Failure to understand and practice them can be fatal.
When two become one
At the crux of multiengine flying issues and dilemmas is a great big what-if: Namely, what if an engine fails or
stops running? And what if that engine quits at the most critical time — during the takeoff phase, right after
liftoff?
It's at times like these that you quickly discover how multiengine flying's "advantages" can turn into deadly
traps. A piston twin with one operative engine doesn't lose half its climb capability — it loses about 80
percent! Where once you climbed out at, say, 1,200 fpm, now you stagger into the air on one engine at a
meager 200-fpm climb rate. This implies obvious problems should compliance with a departure procedure's
climb gradient restrictions be a factor. In other words, you may not be able to outclimb any nearby high terrain
or obstacles.
Airspeed can easily decay under this reduced-power condition, too. Multiengine airplanes weigh more than
singles, and the extra mass means that any loss of thrust translates into sagging airspeed (and the severity of
any impact will be greater). With a windmilling propeller, there's plenty of extra drag to compound the
airspeed problem.
Last — but certainly not least — are the control problems that derive from airspeed losses in engine-out (many
times called one engine inoperative) situations. Basically, this boils down to an asymmetric-thrust situation: If
one engine is producing thrust and the other isn't, then you've got an airplane that wants to yaw and roll in the
direction of the "dead" engine. To stop that yaw, you've got to apply an appropriate amount of rudder force to
the pedal that corresponds to the "good" engine. Thus the origin of the expressions "dead foot, dead engine"
and "working foot, working engine" as memory aids in identifying a failed engine.
VMC — don't go there
Here's a key concept: Rudder effectiveness depends on airspeed. As long as your airspeed is high enough,
rudder pressure will stop any yawing or rolling when an engine quits. This brings us to a discussion of a
critical airspeed — VMC.
VMC is a V-speed that's defined as the minimum control airspeed with the critical engine inoperative, or in
airplanes with counterrotating propellers, one engine inoperative (OEI). If you maintain an airspeed above
VMC, you should theoretically have enough rudder power to counteract any engine-out yawing and rolling.
In twins with propellers that both rotate in the same direction (most often clockwise as viewed from the pilot's
seat) the critical engine is the left engine. Why? Because it's the descending blades that produce the most
thrust, so the biggest thrust vectors are at the right edges of the rotating propeller disks, as viewed from above.
The left engine's maximum thrust zone is closer to the airplane's vertical axis. The right engine's, however, is
far out on the right wing, well away from the vertical axis and able to produce a much greater moment. In this
scenario the left engine is the critical engine because its failure will result in the right engine's generating a
higher yawing moment. Much higher should the right engine have failed. This, in a nutshell, is why the left
engine is called the critical engine.
108
More recent multiengine designs use counterrotating propellers. In this scheme, the left propeller turns
clockwise, the right counterclockwise. You'd still have plenty of asymmetric thrust if an engine were to lose
power, but the critical-engine problem is eliminated because both propellers have their maximum thrust
sectors closer to the centerline of the fuselage.
Centerline-thrust airplanes — the Cessna 336 and 337 Skymasters come to mind — are free of VMC problems
because these airplanes' thrust lines are closely aligned with the longitudinal axis of the airplane. Therefore,
there's no asymmetric thrust. But those who earn their multiengine ratings in centerline-thrust airplanes have
their pilot certificates endorsed for centerline-thrust airplanes only. And there are still the poor climb rate,
propeller drag, and failed-engine identification problems to deal with.
VMC, by the book
By regulation, manufacturers must determine VMC by duplicating a certain configuration during flight tests.
This configuration includes:
A windmilling — or unfeathered — propeller on the dead engine. In airplanes with clockwise-rotating
propellers, this engine is the left, or critical, engine.
Maximum continuous power on the operating engine.
Landing gear extended.
Flaps at the takeoff setting.
Maximum gross weight.
Most aft center of gravity.
Establishment of zero sideslip toward the operating engine. (For minimal drag and best single-engine
performance the airplane should be slipped enough to keep the rudder ball between one-half and three-quarters
of a ball-width out of the center position, toward the operating engine. In addition, you should set up a 5degree bank into the operating engine — "raise the dead," as some instructors say.)
Test pilots slow the airplane in this configuration until they note the airspeed where an uncommanded heading
change occurs. This is the sign that directional control is being lost. Any further loss of airspeed will result in
an uncontrollable yaw, a roll in the direction of the dead engine, and probably a rollover. There's only one way
to stop the yaw: Close the throttle on the good engine and lower the nose to regain the airspeed you need to
restore rudder effectiveness.
Students working on their multi-engine ratings have to do essentially the same drill, in effect making them test
pilots. This has its dangers, and there have been fatal accidents where a practice VMC demonstration turned into
the real thing — especially at low altitudes. Concerns over the safety of this training maneuver led to the
establishment of another airspeed — VSSE. This stands for safe single-engine airspeed, and it gives you a
margin of safety. Usually it's five or so knots higher than VMC, so a student who holds VSSE can be reasonably
assured that these must-know single-engine drills won't develop into departures from controlled flight.
Real-world VMC
Too often, pilots get the idea that VMC is a static number, one that never varies. Wrong. There are a number of
variables that can make an airplane's VMC higher or lower than the number appearing on the airspeed indicator
(it's marked by a red radial line). To prevent inadvertent forays into an airplane's real-world VMC, it's important
for pilots to understand these variables. Here are a few examples of conditions that produce a VMC that's higher
than published in the pilot operating handbook:
Low gross weights, because the yawing moment is stronger when there is less mass to propel.
Landing gear retracted. When the gear are extended they act like miniature rudders and help stabilize the
airplane. When retracted, asymmetric thrust effects are increased.
109
At higher angles of attack, because of a higher drag profile. This means a swifter loss of airspeed at the
moment of engine failure or stoppage.
In a sideslip. Twenty years ago, instructors taught their students to center the inclinometer's rudder ball as part
of configuring a twin for best single-engine flight. No more. Rudder deflection and frontal drag are at a
maximum when holding a wings-level attitude with the ball centered. In this configuration VMC can rise by as
much as 15 knots over the published VMC, and the chance of a single-engine climb can be nullified altogether.
Out of ground effect, where drag is higher.
Low density altitude. Engines produce more thrust in denser air, so asymmetric thrust is greater when an
engine loses power. Conversely, high density altitudes lower VMC because engines and propellers don't
produce as much thrust in thinner air.
Here's something else to bear in mind when practicing VMC demonstrations. At altitude, VMC decreases because
of thinner air and a consequent thrust reduction. But the airplane's stall speed remains the same. At some given
altitude a twin's VMC and stall speed converges. A practice VMC demonstration at too high an altitude can turn
into a disaster because the aircraft may begin its uncontrollable yawing at the same moment it stalls. To avoid
this, many instructors limit their VMC work to density altitudes below 4,000 feet or so.
So, how often do standard conditions exist? How quickly can you identify, verify, and feather a sick engine, or
establish zero sideslip? How often will your airplane be at its most aft center of gravity? The answers are most
likely "never, slowly, and not very often." This gives you an idea of how critical it is to stay away from V MC,
recognize its onset, and plan your takeoffs so as to prevent VMC problems and maximize your airplane's climb
performance.
Takeoff decisions
Bearing all this in mind, how do you perform a takeoff so as to minimize exposure to V MC and maximize your
ability to climb once you're committed to liftoff? More terms come to the fore.
Pilots should, first of all, perform all the necessary preflight calculations of the airspeeds and runway
requirements. Many times you'll hear the term V1, or takeoff decision speed, when referring to takeoff
benchmarks. This is the maximum speed in the takeoff at which the pilot must take the first action (i.e., apply
brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. This
distance is the distance required to accelerate to V1, then stop the airplane on the remaining runway.
Accelerate-stop charts in the performance sections of many POHs let you calculate if you'll have enough
runway to stop, based on atmospheric conditions and the airplane's weight.
V1 has another definition: It's also the minimum distance in the takeoff, following an engine failure, at which
the pilot can continue the takeoff and achieve enough altitude to clear the FAA-standard 50-foot obstacle, or
comply with any other required altitudes in a takeoff profile. The distance needed to commence the takeoff
run, reach V1, have an engine failure, climb out on one engine, and comply with climb requirements is called
the accelerate-go distance.
Many multiengine piston airplanes don't publish accelerate-stop or -go charts. You're more likely to have this
planning information for multiengine turboprops and jets. Even so, it's worth emphasizing how much runway
can be consumed before liftoff, and understand that you may go off the end of the runway if you experience an
engine problem in the takeoff run, know that you won't have enough of a climb rate to clear any obstacles, and
wisely close the throttles and brake for all you're worth. It's much better to hit fences and trees under control at
60 knots than to lose control in the air at 50 feet agl and crash.
Takeoff procedures
110
In multiengine piston airplanes the safest takeoff procedures usually (check your airplane's POH for
the official word) include:
Calculating that you have enough runway to safely take off and clear obstacles, whether you lose an
engine at a critical time or not.
Accelerating to VMC plus five knots.
Lifting off.
Retracting the landing gear once a climb has been established.
Accelerating to VYSE (best single engine rate of climb speed) or VXSE (best single engine angle of
climb) and maintaining these speeds should an engine quit after liftoff.
Accelerating to an en route climb speed once terrain or obstacles are no longer factors.
What if an engine quits….
On the takeoff run, before VMC-plus-five or V1? The answer's easy: Close the throttles and brake,
maintaining directional control on the runway.
Right at VMC or V1? In piston-powered airplanes it's probably best to follow the advice just given,
because your single-engine climb rate and airspeed deterioration may be such that it's better to go off
the end of the runway and take your licks under control than it is to attempt a sickly climb. In
multiengine turboprops and jets, it's usually best to continue the takeoff, because single-engine climb
rates are significantly better.
Just after liftoff, with obstacles or terrain dead ahead? Because of their anemic single-engine climb
rates, it may be best for pilots of piston-powered airplanes to close the throttles, maintain a safe
airspeed, and perform a forced landing straight ahead. In other words, follow the same procedures
you'd use if you were flying a single-engine airplane. In higher-performance twins, maintaining VYSE
or VXSE will probably ensure a safe climbout.
Bottom line
Multiengine airplanes can offer very valuable safety benefits. We always hear about takeoff dangers and
accidents, but you never hear about the many times that twins lose an engine and flights continue safely —
because no accident happened!
That said, it's vital to practice single-engine climbs and engine-out procedures for those times when an engine
conks out at the most dangerous phase of flight — climbing out just after takeoff.
It's also worth remembering that many engine-failure accident scenarios follow a different script. Many times
the first event in the accident sequence happens with an engine failure in the en route phase of flight. The pilot
safely manages the engine problem, only to crash when he botches a single-engine landing, when excessive
floating (there'síless drag with a feathered propeller, and the airplane is slipperier) can lead to runway
overshoots. Or a decision to go around is made too late, airspeed is allowed to dissipate, and/or there's
insufficient power to climb away safely.
111
The Price of Two
The price of stepping up to a twin is measured in more than dollars.
By Richard L. Collins (From AOPA Pilot, July 1990.)
Back in the heyday of general aviation, a sort of social structure developed, based on what you flew. Everyone
aspired to move up the ladder, starting with a basic single like a 172, graduating to a big-engine fixed gear or
retractable single, and finally reaching the pinnacle, the light twin. To pilots flying retractable singles, the most
oft-asked question was "When will you be stepping up to a twin?" Not if—when. It was sacrilege not to want
one. Most tried; everyone couldn't go all the way, and the manufacturers kept adding rungs to the ladder-cabinclass twins, turboprops, and jets-so even highly successful professionals and thriving small businesses couldn't
make it to the top. Now, perhaps because it is so far to the top, the pinnacle for the personal/business user
appears to have become the retractable single. There are only three light twins in production-the Beech Baron
and Piper Seneca and Seminole-and these sold a total of 15 airplanes in the first quarter of 1990. By
comparison, in the first quarter of 1980, which was really past the heyday, light twins accounted for 388
aircraft shipments.
In the used market, much is written about a high-performance single and twin from the same manufacturer of
the same vintage selling for about the same money today, even though when new 10 years ago, the twin cost
more than twice as much. Has this class airplane turned into a pariah in the marketplace, one no longer worthy
of consideration?
Actually a light twin is as good (or better) a personal/business airplane value today as it was 10 years ago. This
is especially true if you are buying used and starting with a level playing field when it comes to initial
purchase price. One thing you have to face up front, however, is insurance. There may well be training and
minimum flight time requirements that should be considered before you even contemplate the purchase of a
twin. If a high insurance premium is attached to the other additional costs of flying a twin, it could just be the
item that broke that rung on the ladder.
If insurance isn't a problem, you can go on to the next step, picking an airplane. Model 58 Barons, with the
long cabin, are the most sought-after light twins and command by far the highest prices because they are,
among other things, excellent air taxi airplanes. Looking at 10-year-old Model 58 Barons, asking prices are in
the mid to upper $100,000 range. Used prices of its sibling single, the A36 Bonanza, don't lag that far behind
because it is probably even more sought after as a single than the Baron is as a twin. The Baron and Bonanza
are good airplanes to use in considering the relationship of the twin to the single, but the comparison would
apply about equally to the Cessna 210 and 3 10, which sell for considerably less money in the used markets.
First, a buyer has to be honest about motives in order to attach the proper significance to the capabilities of the
airplanes being compared. In other words, why do you want a twin? Ego? Performance? Dual systems? The
ability to continue flight after the failure of an engine? Those would probably fit most twin-buyer profiles.
When comparing a twin with a single, the ego factor is definite and dramatic. There is no question that it is
more satisfying to rumble up onto the ramp, or rumble away, to the sound of two engines loping along. Where
an A36 Bonanza and a 58 Baron share the same basic fuselage dimensions, the Baron, because of its bigger
tail, snout, engine nacelles, and greater wingspan, seems by far the larger of the two airplanes. It also feels like
a larger airplane when taxiing as well as in flight. The wing loading of the twin is higher, which should result
in a better ride in turbulence. Certainly an A36 or a Cessna 210 are rewarding airplanes, but Barons and 310s
undoubtedly have a more imposing presence.
Performance is another major attribute of the twin. With two engines of the same horsepower as the single's
one engine and with a maximum takeoff weight only about 50 percent higher, the twin has a lot of extra get up
and go. There's a logical reason for this. The twin has to be able to fly on one engine and to meet a minimum
rate of climb requirement at 5,000 feet if the stalling speed is in excess of 61 knots. If it'll do that, then the
112
output of the other engine can all go into the climb. A 58 Baron climbs at almost 1,700 feet per minute at sea
level in standard conditions, a Bonanza at just over 1,000 fpm. That is the most dramatic performance
difference.
The service ceiling of a Baron is 18,600 feet-2,600 feet higher than a Bonanza. Because of the increase in
weight and drag on the twin, its cruise is only about 30 knots greater than the single's. Where this really pays
off is westbound in the wintertime, With a 50-knot headwind, a Baron will chug along at 150 knots
groundspeed whereas a Bonanza will be back to 120. The slower you go, the bigger the perceived impact of
strong headwinds.
Out flying trips, there would no doubt be an advantage to the Baron-20 minutes here, 30 there, depending on
the length of the trip. The greatest difference would be on trips with strong headwinds, the smallest difference
on trips with strong tailwinds. If you think about it, that is a relationship stacked heavily in favor of the faster
airplane. With a ripping tailwind, you hardly ever feel like you would mortgage property to go faster. Not true
with a headwind. Most of the Barons have more than twice the Bonanza's 74 gallons of usable fuel, so with
more speed, they would also have a range advantage. The Baron would also have a payload/range advantage,
except in a case where the Baron had more heavy options.
The twin's dual systems used to loom large in any comparison, but dual systems are available on Bonanzas and
210s. Both airplanes can also be fitted with airborne weather radar and deice equipment, as can the twins. In
the past 10 or 15 years, systems redundancy and the availability of weather detection and avoidance gear has
become more a simple cost question rather than a twin-versus-single question.
You can make almost everything redundant on the single, but you still have but one basic engine. In the twin,
you have at least the potential of continuing flight after the failure of an engine. The drawback, which has been
discussed for years, is that pilots of twins don't do as well at managing engine failures as pilots of singles. As a
result, proportionately about four times more twins are in fatal crashes after engine failures than singles.
Sweep that aside for this discussion, and assume that we are dealing with a pilot who, with flashing hands,
dashing feet, and a burst of brilliance, will handle with aplomb an engine failure at the worst possible time.
Then you indeed have the ability to fly to an airport after an engine failure. It is on this very consideration that
most decisions to buy a twin are made. "I just don't feel good flying a single (at night, IFR, over cities, over
deserts, over rough terrain)." Fill in the blank with any or all, and unless you are willing to be a VFR day
person over carefully selected routes, the decision to fly a twin has been made.
This is nothing to take lightly because how you feel about what you do with airplanes is an important part of
the equation. An uneasy pilot is not as good a pilot as he should be. We should always be suspicious of
anything mechanical, but to dwell on something, such as an engine failure, takes a lot of the enjoyment out of
flying. In the twin, real comfort comes with an ace pilot at the controls, and there are a lot of us flying around
who believe that, given enough training, we can reach that state.
In this exercise, I have been thinking in terms of 10-year-old airplanes. At this age, some of the available twins
have a lot of time in the log; most of the singles have less. Some of the twins got the hours flying checks and
other things (maybe including baby chickens) around at night. This shouldn't be a harder life than any other
(except maybe for the chicken business), but it does result in a lot of flying time over a relatively short period.
Given good maintenance, this shouldn't be an overriding consideration.
All the 10-year-old airplanes, twins and singles, should have good, serviceable IFR avionics packages, most
with a lot of extras. On some light twins, the prices are all over the place for airplanes of like age. The
pressurized Cessna 340 (at an original MTOW of 5,995 pounds, still a light twin-the line is drawn at 6,000
pounds) is one of these. There are a lot of modifications for 340s, most dealing with power, and an airplane
with all the mods and recently overhauled or remanufactured engines will have an asking price far in excess of
a standard airplane in average shape.
113
The decade-old airplanes are still worth enough money that there is a fair chance they have received adequate
maintenance. You can go back a lot farther than a decade and get twins with a much lower purchase price. In
fact, the supply increases as you start to look at airplanes older than 10 years, but avionics may need an
upgrade, and the airplane may or may not have been maintained to high standards. You can also look at twins
with smaller engines, such as the Beech Travel Air or Piper Twin Comanche, which are both quite efficient
and offer Bonanza performance at relatively small increases in cost.
Whatever price you pay for a used twin, the direct operating costs will be the same as for a newer model of the
same airplane. If the airplane has suffered some maintenance neglect, recovery to a high standard of
airworthiness will be even more costly than with a single because you have two engines to bring up to par. It is
more after the purchase than before that the twin buyer has to make peace with his pocketbook. Using twice as
much fuel to fly 18 percent faster might be rationalized. Spending twice as much for engine and prop overhaul
to fly 18 percent faster also has to be rationalized, along with a generally higher maintenance burden that
comes from having to do all engine-related items twice. The cost of additional initial, as well as recurrent,
training might be added in, but that might also be considered as an enjoyable challenge. Some say that light
twins are more complicated to fly than small jets, and there is some truth to that. There is also a lot of truth to
the fact that many pilots derive pure pleasure from complex operations.
While the cost part contributed to the decline in popularity of the light twin, it is also a moot point. In no area
do we buy for minimum cost and maximum efficiency. If we did, we'd all be driving Yugos and living in
house trailers. If you want it and can afford it, you'll buy it.
Twins make superb personal traveling airplanes and are a lot of fun to fly. All the ingredients are right. But at
some point in the recent past, one strong factor changed and upset the ego part of the consideration, focusing a
pilot's "I want" drive somewhere else. Instrument panels became the compulsion; pilots now appear to
consider that the pinnacle of airplane ownership is related to electronic flight instrumentation, area navigation
systems, moving maps, Stormscopes, radar, engine monitors, and all the other intriguing devices that can be
installed in the panel. Those things and the size of the refrigerator in your T-hangar have simply come to mean
more than the number of engines on your airplane. But twins are still fun, and after an engine stops running....
114
Multi-Engine Pilot Flight Training
115
Lesson Plans for Multi-Engine Course
FAR 61.63(c) Additional class rating. Any person who applies for an additional class rating to be
added on a pilot certificate:
(1) Must have an endorsement in his or her logbook or training record from an authorized instructor
and that endorsement must attest that the applicant has been found competent in the aeronautical
knowledge areas appropriate to the pilot certificate for the aircraft class rating sought;
(2) Must have an endorsement in his or her logbook or training record from an authorized instructor,
and that endorsement must attest that the applicant has been found proficient in the areas of
operation appropriate to the pilot certificate for the aircraft class rating sought;
(3) Must pass the required practical test that is appropriate to the pilot certificate for the aircraft
class rating sought;
(4) Need not meet the specified training time requirements prescribed by this part that apply to the
pilot certificate for the aircraft class rating sought unless the person holds a lighter-than-air category
rating with a balloon class rating and is seeking an airship class rating and
(5) Need not take an additional knowledge test, provided the applicant holds an airplane, rotorcraft,
powered-lift, or airship rating at that pilot certificate level.
LESSON
Flight Time
1
2
3
4
5
6
7
8
9
10 Final Review Flight
Total
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
3.0
12.0
116
Ground
Discussion
0.7
1.0
1.0
1.0
1.0
1.0
1.0
1.5
1.0
1.5
10.7
AIRPLANE MULTI-ENGINE LAND
PRACTICAL TEST STANDARDS
REQUIREMENTS
MINIMUM STANDARDS
MINIMUM ALTITUDE
NORMAL FLIGHT
V SPEEDS
VMC
STEEP TURNS
IFR APPROACHES
SLOW FLIGHT
TRAFFIC PATTERN
ENGINE FAILURE
3,000 AGL
+-100 Feet
+-10 Degrees
+-5 Kts.
+-20 Degrees
+-5 Kts
+- 100 Feet
+- 10 Kts
+- 10 Degrees (Rollout)
45+-5 Degrees Bank
Avoid full scale deflection avoid descent below minimum
+- 10 Kts
+- 5 deg. (20 deg. bank)
+- 10 deg./+ - 50 ft. entry
+- 10 deg./+ - 100 ft+- 100 ft.
+- 5 Kts.
+- 10 deg
+- 100 ft.
+- 10 Kts.
+- 100 ft.
+- 10 Kts.
+- 10 deg
117
Dual
Solo
Grnd
1.0
Flt
0.7
0.0
LESSON 1
OBJECTIVE The student will be introduced to flight in the multi-engine aircraft. Familiarization of the aircraft
controls, instruments, and systems as 4e I .1 as preflight procedures, safety precautions, and use the checklist. A
minimum of three takeoffs or landings will be given.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Ground operations.
a. Visual inspection.
b. Cockpit managementc. Starting engine.
d. Taxiing.
e. Pre-takeoff checks.
Safety Precautions:
a. Ground.
b. Air.
Use of Normal Checklist.
Familiarization Flight-:
a. Collision Avoidance.
b. Taxiing.
c. Takeoff Roll Calls
d. Normal takeoff Climbs (VFR).
e. Straight and Level Flight (VFR/IFR).
f. Turns (shallow, medium, and steep bank).
g. speed Adjustment (VFR)- Descent (VFR).
Airport and Traffic - Pattern Operations.
a. Radio Communication.
b. Traffic Pattern
c. Airport and Runway Markings and Lights
After Landing Procedure.
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be completed when the student has demonstrated familiarization of
the aircraft and an ability to maintain headings within + or - 20 degrees, altitude within + or - 200 feet, and airspeed
within + or - 10 knots of the assigned speed.
INSTRUCTOR COMMENTS:
Date
PrePostLocal
Local
X-C
X-C
Total
Night
Night
Inst
Inst
Flt
Flt
Dual
Solo
Dual
Solo
Dual
Solo
Act
Hood
- Subtotal
Brt Fwd
Total
Instructor Signature
Date
118
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 2
OBJECTIVE During this lesson, instruction will consist of an introduction to maneuvers that are required for the
multi-engine rating. As each maneuvers is introduced, the student will be allowed a period of time in which to practice
each required operation. A minimum of three takeoffs and landings will be given.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Review of Lesson One.
Flight at critically slow airspeed.
Gear and Flaps Up.
Gear and Flaps Down.
other specified configurations.
Stalls (imminent):
Departure Configuration.
Approach Configuration.
Landing Configuration.Steep Power Turns (VFR-IFR).
Effects of Configuration on Engine Out Performance.
Takeoffs and Climbs (PTS Task VFR.).
Normal and Crosswind (VFR)Approaches (PTS Task IX) Approaches and Landings.
Normal and Crosswind (VFR)POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS This lesson will be completed when the student has developed an ability to maintain
headings within + or - 10 degree and altitude within + or - 100 feet during normal flight. During other maneuvers,
headings must be within + or - 20 degree altitude within + or - 200 feet, airspeed within + or 20 knots, and bank within
+ or - 10 degree.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
119
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 3
OBJECTIVE. During this lesson the student will be introduced to the maximum performance takeoff and landing after
which time practice of prior maneuvers will be conducted in order to develop pilot proficiency.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Takeoffs and Climbs.
Normal and crosswind.
Maximum Performance.
Approaches and Landings Normal and Crosswind.
Go Around From Rejected Landing.
After Landing Procedure.
Review:
Flight at critical Slow Airspeeds
Gear and Flaps Up.
Gear and Flaps Down.
other specified Configuration.
Stalls.
Departure configuration.
Approach Configuration.
Landing Configuration.
Steep Turns.
Effects of Configuration - on engine out performance.
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS This lesson will be completed when the student has developed increased proficiency
in the execution of all maneuvers. Headings must be within + or - 10 degrees, bank within + or - 5 degrees, airspeed
within + or -10 knots, and altitude within + or - 100 feet.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
120
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 4
OBJECTIVE. During this lesson the student will be introduced to Vmc Demonstration after which time practice of
prior maneuvers will be conducted in order to develop pilot proficiency.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Vmc Demonstration
Maximum Performance.
Normal and Crosswind.
Go Around From Rejected Landing.
After Landing Procedure.
Effects of Configuration On engine out performance.
Takeoffs and Climbs
Normal and CrosswindMaximum Performance.
Approaches and Landings
Go Around from Rejected Landing.
After Landing Procedures.
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be completed when the student has developed increased proficiency
in the execution of all maneuvers. Headings must be within + or - 5 degrees, bank within + or - 5 degrees, airspeed
within + or -5 knots, and altitude within + or - 80 feet.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- Subtotal
Brt Fwd
Total
Instructor Signature
Date
121
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 5
I. OBJECTIVE. During this lesson, the student will practice prior maneuvers- and will be introduced to Engine-Out
Procedures. Stress the use of the checklist.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Review from Prior Lesson.
Engine-Out Procedures:
Engine failure on Takeoff.
On Ground.
On Takeoff
After Lift-Off.
Maneuvering with one Engine Inoperative.
Feathering and Unfeathering Propellers.
Use of Vyse and Vxse.
Single-Engine Landings
Instrument Flight (OPTIONAL)
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be complete when the student has developed the basic skill to control
the aircraft with one engine inoperative.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
122
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 6
I. OBJECTIVE. This lesson will consist of a review of Lesson One through Six. Maximum Performance Landings,
Rejected Landings, and Manual Gear Extension Procedures will be introduced.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Review Lesson one - Six.
Manual Gear Extension.
Landings:
Maximum Performance.
Rejected:
Two-Engines.
Single-Engine.
Instrument Approaches (optional)
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be complete when the student has demonstrated acceptable skill in
the execution of the maneuvers and procedures listed in Lesson Six and Seven.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
123
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 7
I. OBJECTIVE. This lesson will consist of maneuvers, procedures, and operations contained in the multi-engine
practical test guide, VFR only.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Standard Instrument Flight.
Multi-Engine operation.
Ground Operations.
Airport and Traffic Pattern Operations.
Takeoffs and Climbs.
Multi-Engine Maneuvers.
Emergency Operations.
Approaches and Landings.
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be completed when all maneuvers and procedures are performed at
the proficiency level of a Multi-Engine Pilot (VFR ONLY). The instructor will schedule the Graduation Flight at this
time.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
124
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.5
0.0
LESSON 8
I. OBJECTIVE. This lesson will provide an opportunity for the student to acquire the additional skill that is required of
the instrument rated pilot applicant for the Multi-Engine Land Class Rating.
Grade
Student
(1,2,3)
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Transition from Enroute:
Power settings
Configuration
Holding Pattern: (Both engines operating/ single engine)
Direct
Parallel
Tear Drop
Instrument Approaches: (Both engine operating/single engine)
ILS
VOR and VOR/DME
ADF
Radar (optional)
Missed approach Procedures
Both engines
Single-engines
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS: This lesson will be complete when the student demonstrates increased skill in MultiEngine Instrument Flight.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
125
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
1.0
Flt
1.0
0.0
LESSON 9
I. OBJECTIVE: During this flight the student will review all maneuvers, procedures, and operations contained in the
Multi-Engine Course.
Grade
(1,2,3)
Student
Initials
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
Takeoff and Landings.
Steep Turns.
Maneuvering During Slow Flight.
Stalls
Instrument Flight
Engine-Out Procedure:
Maneuvering with one engine inoperative.
Use of Vyse/Vxse.
Effects of Configuration on Engine-Out Performance.
Vmc Demonstration.
Instrument Approaches.
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. The students will demonstrate proficiency that meets or exceeds the standards of
performance for the issuance of a Multi-Engine Land Class Rating - Instrument Privileges. Additional instruction will
be assigned, if necessary, to meet the course completion standards.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
126
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
Dual
Solo
Grnd
3.0
Flt
1.5
0.0
LESSON 10
GRADUATION / FINAL REVIEW FLIGHT
I. OBJECTIVE: During this flight, the Chief Flight Instructor or his assistant will determine if the student has gained
the proficiency necessary to graduate from this course.
Grade
(1,2,3)
PREFLIGHT DISCUSSION:
1. Flight profile for the current flight
FLIGHT OPERATIONS TASKS
PREFLIGHT PREPARATION
Certificates and Documents b: Obtaining Weather Information
Cross Country Flight Planning
Night Flight Operations
Aeromedical Factors
MULTI-ENGINE OPERATION
Operation of Airplane Systems
Emergency Procedures
Determining Performance and Limitations
Flight Principles-- Engine Inoperative
Use of Minimum Equipment List
GROUND OPERATIONS
Visual Inspection
Cockpit Management
Starting Engine
Taxiing
Pre-Takeoff Check
AIRPORT AND TRAFFIC PATTERN OPERATIONS
Radio Communications and ATC Light Signals
Traffic Pattern Operations
Airport and Runway Marking and Lighting
TAKEOFFS AND CLIMBS
Normal and Crosswind Takeoffs and Climbs
Maximum Performance Takeoff and Climbs
INSTRUMENT FLIGHT
Engine Failure During Straight-And-Level Flight and Turns
Instrument Approach--- All Engine Operating
Instrument Approach--- One Engine Inoperative
FLIGHT AT CRITICALLY SLOW AIRSPEEDS
Power-Off Stalls
Power-On Stalls
Maneuvering During Slow Flight
Steep Power Turns
Spin Awareness
MULTIENGINE OPERATIONS
Maneuvering with One Engine Inoperative
VMC Demonstration
Engine Failure During Flight (by Reference to Instruments)
127
Student
Initials
Effects of Configurations During Engine Inoperative Performance
EMERGENCY OPERATIONS
Systems and Equipment Malfunctions
Maneuvering with one Engine Inoperative
Emergency Descent
Engine Inoperative Loss of Directional Control Demonstration
Engine Failure on Takeoff Before Vmc
Engine Failure En Route
Engine Failure After Lift Off
Approach and Landing with an Inoperative Engine
Systems and Equipment Malfunctions
Emergency Equipment and Survival Gear
APPROACHES AND LANDINGS
Normal and Crosswind Approaches and Landings
Go-Around From Rejected (Balked) Landing
Maximum Performance Approach and Landing
After-Landing Procedures
Approach and Landing with an Inoperative Engine (Simulated)
POSTFLIGHT DISCUSSION:
1. Review of current lesson and progression
2. Preview of next lesson
COMPLETION STANDARDS. This lesson will be completed when all maneuvers and procedures are performed at
the proficiency level of the Practical Test Standards for Multi-Engine Class Rating Instrument Privileges.
INSTRUCTOR COMMENTS:
Date
PreFlt
PostFlt
Local
Dual
Local
Solo
X-C
Dual
X-C
Solo
- - Subtotal
Brt Fwd
Total
Instructor Signature
Date
128
Total
Night
Dual
Night
Solo
Inst
Act
Inst
Hood
Inst
Sim
129
Transition Courses For Complex Single-Engine And Light Twin-Engine
Airplanes
1974
DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION
Preface
This publication is intended for use by certificated airplane pilots who wish to transition to more complex
single-engine or light twin-engine airplanes.
An extremely wide range is available today in the single-engine class and in the light twin-engine class of
airplanes. Change from the simple to the sophisticated has occurred rapidly in recent years. Pilots who have
been inactive or who have not been introduced to the more modern airplanes are encouraged to follow the
syllabus of training offered in this advisory circular. Greater knowledge and skills are needed for the
efficient and safe operation of today's more powerful aircraft.
This publication is offered as a guide to the procedures and standards to be followed for a thorough and
comprehensive checkout in these airplanes. The conscientious application and adherence to the scope of
coverage recommended in the syllabus should result in a more competent, effective, and efficient pilot.
The transition courses have been prepared by the Flight Standards Service of the Federal Aviation
Administration and issued as Advisory Circular 61-9B.
Comments regarding this publication should be directed to Department of Transportation, Federal
Aviation Administration, Flight Standards Technical Division, P.O. Box 25082, Oklahoma City, Oklahoma
73125.
TRAINING FOR CHECKOUTS
Pilots preparing to check out in additional types of airplanes may find it helpful to follow a prescribed set
of procedures and standards in training. This guide outlines a course of training for each of the two classes of
airplanes: the complex single-engine and the light twin-engine.
This training should be conducted by a competent flight instructor who is certificated in the class of
airplane and who is thoroughly familiar with the make and model. Characteristics of classes of airplanes as
well as makes and models vary considerably, one from another.
While this guide is complete in its outline of the material to be covered, the recommended syllabus for
transition training is to be considered flexible. The arrangement of the subject matter may be changed and
the emphasis may be shifted to fit the qualifications of the trainee, the airplane involved, and the
circumstances of the training situation, provided the prescribed proficiency standards are achieved.
The training times indicated in the syllabuses are based on the capabilities of a pilot who is currently
active and fully meets the present requirements for the issuance of at least a private pilot certificate. The
time periods may be reduced for pilots with higher qualifications, or increased for pilots who do not meet the
current certification requirements or who have had little recent flight experience.
Complex Single-Engine Airplanes
The syllabus in figure 1 is designed to prepare a certificated single-engine pilot, without previous
experience in "complex" airplanes, to operate one such airplane type competently.
130
For purposes of this syllabus, a "complex" single-engine airplane is one equipped with flaps, a
controllable propeller, and a retractable landing gear.
Light Twin-Engine Airplanes
The syllabus in figure 2 may be used for either of two purposes; (1) to check out a private or commercial
pilot who holds a multiengine rating on a new type of light twin-engine airplane; or (2) to prepare a private
or commercial pilot without previous multiengine experience to take the required multiengine class rating
flight test from a qualified pilot examiner or FAA inspector. The training program assumes that the student
is currently qualified in at least one complex airplane type.
To be fully effective, this syllabus should be followed and the training conducted by a flight instructor
familiar with the performance and characteristics of light "twins" in general and with the significance and use
of critical performance speeds. The instructor should be fully qualified in the airplane type concerned.
CHECKOUT PROCEDURES AND STANDARDS
Preflight Examination
Before taking off on his checkout flight, a pilot should pass a test on the airplane to be used, its systems,
limitations, performance, emergency procedures, and approved operating procedures. This test may consist
in part of a written quiz, or may be wholly an oral examination by the check pilot.
The preflight examination should cover at least:
a. The approved Airplane Flight Manual, Owner's Handbook, and official placards which prescribe
operating procedures and limitations.
b. A working knowledge of cruising speeds at various altitudes, power settings, fuel consumption,
endurance, takeoff and landing distances, and rates of climb and descent.
c.
Normal and emergency operation of aircraft systems and special equipment.
d.
Practical computation of various combinations of the permissible loadings using available loading
diagrams or graphs.
e.
A thorough line check of the airplane to be used, using a checklist provided by the manufacturer or
operator. If no official checklist is available, the check must be made in accordance with an orderly
procedure that covers all critical items. The presence of all required certificates, documents, and placards,
and the fuel and oil supply should be checked. The inspection must cover all airworthiness items that can be
investigated by an external examination. The pilot must know the significance of all unsatisfactory items
noted, and the appropriate corrective action to be initiated by the pilot for each.
Flight Maneuvers and Procedures
Coordination and Planning Maneuvers
Standard coordination and planning maneuvers should be performed to demonstrate that the pilot is
familiar with the airplane's performance and flight control responses. These may be very simple maneuvers
or relatively complex, ranging from medium-banked turns (20[dg] to 30[dg]) and 720[dg] power turns to
chandelles and lazy eights. Coordination and planning maneuvers should be demonstrated in both directions,
131
at various speeds within the normal airspeed range of the airplane, and with various flap and landing gear
configurations.
The pilot should perform all standard coordination maneuvers without completely deflecting the ball
outside the center reference lines of a standard slip-skid indicator. Prolonged turns should be stopped within
10[dg] of the assigned heading, and altitude should be maintained within 100 ft. of the assigned altitude
during level flight maneuvers.
Ground Pattern Maneuvers
Any of several standard training maneuvers may be used to demonstrate that the pilot is able to accurately
control his path over the ground, and anticipate turns to new courses. Among these are S-turns across a road,
rectangular courses, turns about a point, or eights around pylons. The demonstration of rectangular courses
may be accomplished in the airport traffic pattern if other traffic permits.
The pilot should be able to maintain the desired track over the ground by crabbing into any existing wind,
anticipating the crab on recovery from turns, and maintaining proper coordination of the rudder and aileron
controls. During pattern maneuvers, he should hold his altitude within 100 ft. of the altitude assigned. He
should be able to operate by ground references without prolonged diversion of attention from his engine
instruments and his vigilance for other traffic.
Flight at Minimum Controllable and Landing Approach Airspeeds
Climbs, descents, and level flight on straight courses and in medium banked turns should be demonstrated
at minimum controllable and landing approach airspeeds with appropriate power settings. The minimum
controllable speed used should be such that any further reduction in airspeed or increase in load factor would
result in immediate indications of a stall. The landing approach speed should be 1.3 to 1.4 times the poweroff stalling speed in cruise configuration.
The pilot should also demonstrate the smooth, prompt transition from cruising to landing approach
airspeed, and the use of flaps and gear to effect descents from level flight at approach speed without
changing the power setting.
The pilot should be able to control his airplane positively and smoothly at the appropriate speed, and
maintain an airspeed within 5 kts. of the desired speed. He should make the transition from cruising speed to
landing approach speed without varying more than 10[dg] from the desired heading nor more than 100 ft.
from the desired altitude.
Stalls from All Normally Anticipated Flight Attitudes
The recovery from stalls entered with and without power should be demonstrated. Emphasis should be
placed on the recovery from the three critical stall situations: takeoff and departure, approach to landing, and
accelerated stalls.
Recovery should be initiated as soon as the first physical indication of a stall is recognized, except that in
single-engine airplanes at least one stall should be allowed to develop until the nose pitches through level
flight attitude before recovery is initiated. Stall warners should be deactivated for stall demonstrations,
except in airplanes for which they are required equipment. Stall recoveries should be demonstrated with and
without power, and with various configurations of gear and flaps.
Stall recovery performance will be evaluated on the basis of prompt stall recognition and smooth positive
recovery action. The pilot's ability to establish a precise stall entry situation is not a requirement, so he may
132
be coached or assisted in setting up the required stall situations. Recovery should be effected smoothly with
coordinated use of the flight controls and the least loss of altitude consistent with prompt recovery of positive
flight control.
Maximum Performance Operations
Short-field and soft-field takeoffs and landings should be required in accordance with procedures
specified in the Airplane Flight Manual or Owner's Handbook and the FAA Flight Test Guides. Special
attention should be paid to flap and trim settings, power usage, and the use of correct airspeeds. The use of
the best angle-of-climb and rate-of-climb airspeeds becomes more critical as speeds increase and the
cleanness and efficiency of airplanes improve.
In multiengine airplanes, it is important for the pilot to know and observe two sets of performance speeds:
one for normal use and one applicable to operation with one engine inoperative. To demonstrate maximum
performance short-field and soft-field takeoffs, lift-off should be initiated just below the all-engine best
angle-of-climb speed, unless it is slower than the engine-out minimum control speed, in which case the
engine-out minimum control speed should be used. The best all-engine angle-of-climb speed should be
attained, and maintained to the height of an assumed obstruction, such as a fence or row of trees, after which
normal climb speed should be smoothly attained.
Optimum power, loading, and flap settings for various density altitudes may be found in the Airplane
Flight Manual or Owner's Handbook. In efficient high-performance airplanes the proper application of these
factors will produce a significantly better performance which can be readily demonstrated.
Control by Reference to Flight Instruments
During his checkout in a new airplane type, the pilot should demonstrate his ability to control the airplane
manually in flight by reference to instruments. No IFR flight procedures, as such, need be performed, but the
pilot should be able to perform the following maneuvers smoothly and with confidence, using all
instrumentation installed in the airplane.
1.
Level flight, climbs, turns, and descents. Climbs and descents should be performed at constant
airspeeds, using standard rates of climb and descent, usually 400 to 500 ft. per minute depending on the
performance of the airplane used. Turns should be performed at the standard rate, and be stopped within
10[dg] of an assigned heading.
2.
Recovery from unusual attitudes. The pilot should be able to recover
positively and smoothly from both nose-high and nose-low unusual attitudes established by the check pilot.
The attitudes used should be moderate displacements from normal flight, characteristic of errors due to
diversion of attention from the instruments during instrument flight. They should include climbing turns,
incipient power spirals, increasing or decreasing angles of bank, and significant variations in airspeed.
Recovery should be smoothly effected to a straight and level flight by reference to instruments without
imposing any excessive load factors or involving airspeeds which are dangerously close to the placarded
maximum speed or to stalling speed.
Use of Radio, Autopilot, and Special Equipment
Radio
The pilot should demonstrate the use of all radio equipment in the airplane for communications and VFR
navigation. The pilot should be able to operate each transmitter and receiver and use radio navigation
equipment to establish bearings and tracks by radio signals received. He should be able to operate DME
133
(distance measuring equipment) and transponder if installed, and have a general knowledge of their
principles of operation and limitations.
Operation of radio equipment should include a knowledge of the location of associated fuses and circuit
breakers, and how to replace or reset them. It should also include a general knowledge of the capabilities and
limitations of each radio installation.
Autopilot
If an autopilot is installed, the pilot should demonstrate its use, including indexing, engaging,
disengaging, and resetting course and altitude while it is engaged, if permissible.
He should also demonstrate a working knowledge of its limitations, possible malfunctions, overpowering
by the pilot, and emergency disengagement.
Special Equipment
The pilot should be familiar with and demonstrate the use of any special equipment installed, such as
flight director, oxygen systems, pressurization systems, and automatic feathering devices. The
demonstration should include a working knowledge of the limitations and the common failures of the
equipment, and of the special precautions to be taken in equipment operation.
Emergencies
Emergency Operation of Aircraft Systems
The emergency operation of all airplane systems should be performed when practicable. Such operations
should include the emergency extension of gear and flaps, the use of boost pumps, fuel transfer, replacement
or resetting of fuses or circuit breakers, and the isolation of specified electrical circuits. The operation of
pressure fire extinguisher systems, and such operations as the emergency extension of the landing gear by
CO 2 should be explained and simulated. The emergency operation of the pressurization and oxygen system
should be covered on airplanes so equipped.
Forced Landings (Single-Engine Airplanes Only)
The examiner should close the throttle smoothly at unannounced times during the checkout, and request
the applicant to proceed as he would in the
event of an actual power failure. No simulated forced landing will be given where an actual safe landing
would be impossible. At least once, during the checkout, the pilot should demonstrate a landing from a glide
with the engine throttled at traffic pattern altitude. Performance will be evaluated on the basis of the pilot's
judgment, planning, technique, and safety.
Engine-Out Emergencies (Multiengine Airplanes)
A pilot checking out for the first time in a multiengine airplane should practice and become thoroughly
familiar with the control and performance problems which result from the failure of power in one engine
during any normal flight condition. He should practice the control operations and precautions necessary in
such cases, and be prepared to demonstrate these on his multiengine rating flight test.
1.
Propeller leathering or engine shutdown. The feathering of one propeller should be performed in
all airplanes equipped with propellers which can be safely feathered and unfeathered in flight. If the airplane
134
used is not equipped with featherable propellers, or, is equipped with propellers which cannot be safely
feathered and unfeathered in flight, one engine should be shut down in accordance with the procedures in the
Airplane Flight Manual or Owner's Handbook. The prescribed propeller setting should be used, and the
emergency setting of all ignition, electrical, hydraulic, and fire extinguisher systems should be demonstrated.
Proficiency will be evaluated on the basis of the control of heading, airspeed, and altitude; the prompt
identification of a simulated power failure; and the accuracy of shutdown and restart procedures as
prescribed in the Airplane Flight Manual or Owner's Handbook.
Feathering for training and checkout purposes should be performed only under such conditions and at
such altitudes and positions that a safe landing on an established airport could be readily accomplished in the
event of difficulty in unfeathering.
2.
Engine-out minimum control speed (V mc) demonstration (small multiengine airplanes only).
Every small multiengine airplane checkout (except airplanes with centerline thrust) should include a
demonstration of the airplane's engine-out minimum control speed. The engine-out minimum control speed
given in the Airplane Flight Manual, Owner's Handbook, or other manufacturer's published limitations is
determined during original airplane certification under conditions specified in the Federal Aviation
Regulations. These conditions are normally not duplicated during training or on flight tests. It is also
recognized that in all airplanes there is a density altitude above which the stalling speed is higher than the
engine-out minimum control speed.
A thorough discussion, prior to flight, of the factors affecting engine-out minimum control speed will be
required. This discussion and the following demonstration will satisfy the operational objective in regard to
identifying the controllability problems which can result from flight at too slow an air. speed when an engine
failure occurs. The demonstration should be performed at a safe altitude. This maneuver will demonstrate
the engine-out minimum control speed for the existing conditions and makes no effort to duplicate Vmc as
determined for airplane certification.
With the gear and flaps tip, the airplane will be placed in a climb attitude representative of that following
a normal takeoff. With both engines developing as near rated takeoff power as possible, power on the
critical engine (usually the left) will be reduced to idle (windmilling, not shutdown). The airspeed will then
be reduced slowly with the elevators until directional control can no longer be maintained. At this point,
recovery will be initiated by simultaneously reducing power on the operating engine and reducing the angle
of attack by lowering the nose. Should indications of a stall occur prior to reaching this point, recovery will
be initiated by reducing the angle of attack. In this case, a minimum engine-out control speed demonstration
is not possible under existing conditions.
If it is found that the minimum engine-out control speed is reached before indications of a stall are
encountered, the pilot should demonstrate his ability to control the airplane and initiate a safe climb in the
event of a power failure at the published engine-out minimum control speed.
For this demonstration, with the gear and flaps set for takeoff, the airspeed should be slowed at reduced
power to the minimum speed determined above. Rated takeoff power should be applied smoothly, and a
climb initiated at the minimum engine-out minimum control speed specified in the approved Airplane Flight
Manual or Owner's Handbook. The check pilot should throttle one engine to simulate a loss of power, and
request the pilot to maintain heading and continue a climb (or minimum sink) at the engine-out best rate-ofclimb airspeed.
The gear and flaps should be retracted in accordance with the emergency procedures prescribed in the
Airplane Flight Manual, or Owner's Handbook, and the throttle on the windmilling engine may be advanced
sufficiently to simulate a feathered propeller (on airplanes with feathering propellers only).
135
Performance will be evaluated on the basis of the pilot's being able to maintain his heading within 15[dg]
and his bank within 10[dg], and the accuracy of his operation and trim procedures. Any attempt to continue
level or climbing flight at less than the published minimum engine-out control speed after a simulated or
actual power failure will result in immediate disqualification on a flight test in a multiengine airplane.
3.
Engine-out best rate-of-climb demonstration. The pilot should practice and demonstrate the use
of the best engine-out rate-of-climb speed shown in the Airplane Flight Manual or Owner's Handbook.
This speed should be demonstrated with one engine set to simulate the drag of a feathered propeller or a
propeller actually feathered, except that in airplanes without feathering propellers one engine should be cut
off or idling. The prescribed speed should be carefully maintained for at least 1 minute after the airspeed has
stabilized, and the resulting gain or loss of altitude should be carefully noted. For comparison, climbs may
be attempted at other airspeeds within the normal operating range of the airplane used.
4.
Effects of configuration on engine-out performance. The pilot should also practice and
demonstrate the effects (on engine-out performance) of various configurations of gear, flaps, and both; the
use of carburetor heat; and the failure to feather the propeller on an inoperative engine. Each configuration
should be maintained at best engine-out rate-of-climb speed long enough to determine its effect on the climb
(or sink) achieved. Prolonged use of carburetor heat at high power settings should be avoided.
5.
Maneuvering with an engine-out. Engine-out maneuvering is usually practiced in conjunction
with the feathering demonstration described in para. 1, above. It is acceptable, however, to conduct this
demonstration with one engine set to simulate the drag of a feathered propeller if the airplane is equipped
with feathering propellers. In airplanes which are not so equipped, maneuvering should be demonstrated
with an engine cut off completely, or idling.
Straight and level flight and medium (20[dg] to 30[dg]) banked turns toward and away from the
inoperative engine should be practiced. The pilot should be able to maintain altitude within 100 ft. of the
initial altitude if the airplane is capable of level flight with an engine out, or the airspeed within 5 kts. of the
best rate-of-climb speed in an airplane that is not capable of level flight under the existing conditions.
6.
Approach and landing with an engine-out. At least once during his checkout, the pilot should
perform an approach and landing with an engine throttled to simulate the drag of a feathered propeller, or, if
featherable propellers are not installed, an engine throttled to idling.
Evaluation will be based on the correct operation of the airplane systems, the appropriate handling of trim,
observance of the proper traffic pattern or approach path, airspeed and altitude control, accuracy of
touchdown, and control during rollout.
Emergency Descents (Pressurized Airplanes Only)
During checkout in a pressurized airplane, the pilot should practice and demonstrate emergency descents,
such as may be necessitated by explosive decompression, in accordance with procedures prescribed in the
Airplane Flight Manual or Owner's Handbook.
Descents should be initiated and stabilized, but prolonged descents should be avoided because of possible
hazard to air traffic. The airspeed or Mach number used for the demonstration should be approximately 10
percent less than the airplane's structural limitation (V mo, M mo) to provide a margin for error. When a
Mach limitation is controlling at operational altitudes for the airplane used, the descents should be arranged
to require the transition from the observance of a Mach limitation to an airspeed limitation. No emergency
descents should be practiced near or through clouds.
136
FLIGHT INSTRUCTORS' ENDORSEMENTS
AND RECOMMENDATIONS
Logbook Endorsements
A flight instructor who has checked out a certificated pilot in a new type of airplane, single-engine or
multiengine, should enter and certify the checkout in the pilot's logbook. Such certification should include
the date, precise designation of the airplane type involved, and the extent of the checkout conducted. Figure
3 is an example of such a certification.
CHECKOUT IN PIPER COMANCHE MODEL PA-24-260 IN ACCORDANCE WITH FAA ADVISORY
CIRCULAR 61-9B SATISFACTORY, 3/14/74.
/s/ DAVID LIVINGSTON, CFI 386423
FIGURE 3. Flight Instructor's Certification
Multiengine Rating Recommendation
A certificated flight instructor who has checked out a certificated pilot in a multiengine airplane should
execute the certification in the pilot's logbook illustrated in figure 3.
If the pilot does not already hold a multiengine rating, the flight instructor should also provide him with
an official recommendation for the multiengine rating practical test, using FAA Form 8420-3, as depicted in
figure 4.
Graduation Certificate
An agency or operation that conducts transition courses for pilots, at pilot training clinics or in the course
of its regular pilot training operations may wish to award formal graduation certificates in addition to the
regular endorsements and recommendations. A sample for such a graduation certificate is illustrated in
figure 5.
137
* Multi-Engine Flying
Q: In an underpowered twin, what is the role of the second engine?
A: It doubles your chance of engine failure, and it will fly you to the scene of the accident.
1.1 Normal Operations
In normal conditions, operating a twin is not very different from operating a heavy, high-powered, complex
single. Even so, the weight, power, and complexity may be more than you are accustomed to. In particular:
 The typical twin will operate over a wider range of speeds than the typical single. To be specific: in a
Cessna 172, you might climb at 78 knots and cruise at 105 knots (a ratio of 1.3), whereas in a Seneca
II you might climb at 90 knots and cruise at 170 knots (a ratio of 1.9). When you level off following
a climb, the Seneca will take much longer to accelerate to its cruising speed. After the level-off, you
let it accelerate for a few seconds, and then trim it — but then it will accelerate some more and you
will have to trim it some more. You should plan on prolonged acceleration and repeated trimming.
 A typical twin has a much higher stalling speed than a typical single. 1 Other critical speeds are
increased in proportion. One consequence is that you will notice that normal turns in the traffic
pattern require considerably more room.
 The rate of climb will be considerably higher, so you will reach pattern altitude sooner. The pitch
angle during climb will be higher.

1.1.1 Multi-Engine Takeoff
In a multi-engine aircraft, an engine failure shortly after takeoff is a very critical situation. It places
considerable demands on the pilot. Make sure you know what to do; brief yourself in detail before the
takeoff.
Early in the takeoff roll, verify that both engines are developing the same amount of power. If the aircraft is
trying to pull to one side, you've got a problem. Also, check the engine gauges to make sure (a) you've got
the normal RPM on both engines, (b) you've got the normal manifold pressure on both engines, and (c)
you've got the normal fuel flow on both engines. The instruments that measure these three quantities are
usually a single gauge with two needles, so if you notice that the needles are split you've got a problem.
If anything funny happens while there is runway remaining ahead of you, close both throttles immediately
and stop straight ahead. Even if you are airborne, close the throttles and re-land if there is sufficient runway
length. Indeed, even if the remaining runway is not quite enough, you might want to land on it: Suppose that
because of density altitude or whatever, your aircraft has poor single-engine climb performance. You will
sustain vastly less damage if you land and run off the end of the runway at low speed, rather than making an
unsuccessful attempt to climb out on one engine.
You really don't want to be airborne at a speed below VMC, i.e. at a speed where you can't maintain
directional control on one engine. In many aircraft, you should aim for a lift-off speed of VMC plus 5 knots.
To make sure you do not lift off too soon, you can delay rotation until reaching VMC. You can semi-rotate
earlier if you want; just make sure you don't rotate to a pitch attitude that will cause liftoff below the desired
airspeed. After liftoff, climb while accelerating to VY (which ought to be greater than or equal to VYSE).
In many twins, VMC is essentially equal to the stalling speed. In others, however, it is considerably higher,
which makes soft-field takeoffs problematic. You don't want to lift off at "the lowest possible airspeed" (like
you would in a single) since if you lost an engine at that speed you'd have a big problem: uncontrollable yaw.
It would be a lot safer to lift off at VMC or higher, even if this means staying away from soft, bumpy fields.
Most of the rest of this chapter is devoted to the procedures and principles of engine-out flying.
1.2 Engine Out Scenarios
138
This section discusses some of the things you might observe when an engine fails, and what you can do in
response.
1.2.1 Rejected Takeoff; Balanced vs. Unbalanced Field
Airliners are not allowed to take off unless the available runway exceeds the "balanced field length"; that is,
the runway must be sufficiently long that even if an engine fails at the most critical point during takeoff, the
airplane can either stop on the remaining runway, or continue the takeoff and get safely airborne on the
remaining engine(s).
In contrast, general-aviation light twins are not required to restrict themselves to "balanced field" takeoffs.
Suppose you lose an engine during the takeoff roll on a short runway. Even if your plane would have done
fine on a long runway, on a short runway there will be a period during the middle of the takeoff roll where
you can neither stop nor continue safely on one engine. In such a case you must shut down the good engine
and try to stop. It is much better to hit the trees at the end of the runway when you are "almost" stopped then
to hit them when you are "almost" at full flying speed. This seems obvious on paper, but when you are in the
cockpit it takes a lot of willpower to actually shut down the good engine. Think about this. Promise yourself
that you will do it right.
1.2.2 Climb
For our next scenario, suppose you are at a reasonable altitude, climbing with full power on both engines.
Then one engine fails. One of the first things that you will notice is that the single-engine rate of climb is not
half of the two-engine rate of climb. No, indeed! The reason is simple: as shown in figure 1.1, when an
engine is shut down, you are not splitting the difference between two-engine performance and level flight;
you are splitting the difference between two-engine performance and a zero-power descent.
Figure 1.1 - Two-, One-, and Zero-Engine Performance
The curves in the figure are roughly representative of a Piper Apache, a well-known light twin trainer. Point
A corresponds to the two-engine best rate of climb, 1150 fpm at 86 knots. Point B corresponds to the singleengine best rate of climb, 160 fpm at 82 knots. (These numbers apply to a fully-loaded aircraft at sea level in
the clean configuration.) We see that the single-engine rate of climb is less than 15% of the two-engine rate
of climb.
At density altitudes above 5000 feet the Apache cannot climb at all on one engine. Also, if the engines,
propellers, and paint job are not quite factory-new, the performance will be even less than these book values
suggest.
You must not allow yourself to think that just because airliners can climb with an engine out, your favorite
light twin can climb with an engine out.
It is legal to operate a light twin with anemic or nonexistent single-engine climb performance. In such cases,
engine failure at low altitude is perhaps the most critical situation that arises in general aviation with any
appreciable frequency. Like a single-engine aircraft with partial power failure, you need to make a forced
139
landing. The problem with the twin is that (because of the asymmetric power) if you mishandle the situation,
your chance of getting into a spin is much higher than it would be in a single.
On the other hand, even if you are not climbing, you are probably not descending very fast. You can treat it
as another "noisy glider". If you start out several thousand feet above the ground, you can probably travel
dozens of miles while gradually descending. Look around and find a nice place for a forced landing.
1.2.3 Slip String
Generally, the best way to fly any airplane is to keep the airflow aligned with the fuselage. Alas, in a multiengine aircraft with asymmetric thrust, it can be rather tricky to perceive just what the slip angle is. The most
direct way to get information about this angle is to use a slip string.
To create a slip string, tape a piece of yarn to the nose of the airplane, in front of the center of the window
where you can see it. Leave a foot or two of yarn dangling free, so it will align itself with the airflow.
In typical aircraft, the fuselage accelerates the sideways flow, increasing the sensitivity of the string. That is,
the angle of the string is larger than the actual slip angle.
Even in ordinary single-engine aircraft, slip strings work surprisingly well. The straight-back component of
propwash decreases the sensitivity somewhat, and the helical component of propwash biases the string
slightly to one side.
Actually, even in a multi-engine aircraft, the string can be slightly biased by the helical propwash. The effect
is zero if you have counter-rotating props with equal power settings, but if both props go the same way
and/or one of them is shut down, there will be some helical propwash. The air does not have to be directly
downstream of a propeller in order to participate in the helical motion. If you put a second slip string
underneath the nose, it would be biased to the opposite side, but it would be a bit hard to see.
The slip string is commonly referred to as a "yaw string", even though it measures the slip angle, not the yaw
angle (i.e. heading) or yaw rate. The slip angle measures the angle between the fuselage and the relative
wind, whereas yaw is defined relative to some fixed spatial direction. Heading and heading change (i.e. yaw
rate) are easy to perceive by looking out the window, while it is not easy to perceive slip angle except by
reference to a slip string. Heading can also be perceived using the directional gyro (heading indicator), and
yaw rate can be perceived using the rate-of-turn gyro or by observing the rate of motion of the directional
gyro.
1.2.4 Coordination
For our next scenario, imagine that you are in level flight at cruise airspeed at a comfortable altitude. Let's
also suppose that your airplane has a slip string installed. Then (surprise!) an engine fails. To simplify the
discussion, let's suppose the right-hand engine 2 is the one that quits. You will immediately notice that the
airplane will develop a slip angle. In this case, the airplane will yaw to the right, shown in figure 1.2. This is
because the drag of the airplane is more or less symmetrically disposed, while the thrust is now quite
asymmetric. As always, two forces with a lever arm between them create a pure torque.
Figure 1.2 - Engine Out: Torque due to Asymmetric Thrust
140
This torque will produce an initial heading change. This will be a pure yaw; that is, it will change the
direction the airplane is pointing without any immediate change in the direction the airplane is going. You
will observe that the slip string is off-center to the right, indicating an asymmetric airflow. Then, after a short
time (a second or so), the torques will come back into equilibrium, because of the airplane's natural yaw-axis
stability (as discussed in section 8.2). That is, the uncoordinated airflow hitting the rudder will create a
torque that opposes the asymmetric thrust.
Figure 1.3 - Engine Out: No Pilot Action
At this point, you could either (i) sit there and be a spectator, as shown in figure 1.3, or (ii) press on the left
rudder pedal to center the slip string, as shown in figure 1.4. From the point of view of directional control,
your choice doesn't matter very much. That is, in case (i) the airflow strikes the whole airplane (rudder
included) at a nonzero angle, while in case (ii) the airflow strikes the airplane at a zero angle, with the rudder
deflected. In either case, the amount of tail force produced is approximately the same. The most important
difference is that the airplane will climb better in case (ii), because the airflow will be aligned with the
fuselage.
Figure 1.4 - Engine Out: Correct Compensation
Let's see what happens after the yaw-axis torques have returned to equilibrium. Let's assume for now that
you are keeping the wings level. In case (i), the airplane will make a steady turn toward the dead engine. This
is obviously a boat turn, due to the uncoordinated airflow striking the fuselage. This will be a genuine CMturn, changing the direction of motion of the center of mass; the heading will follow the CM-turn in order to
maintain a constant slip angle.
What is perhaps more surprising is that even in case (ii), if you keep the wings level the plane will make a
CM-turn toward the dead engine (toward the right in this case). It will not turn as rapidly as in case (i), but it
will turn nonetheless. The reason is that the rudder force, in addition to creating a torque, is creating an
unbalanced force. This force is changing the direction of motion of the center of mass. A possible (but nonoptimal) way to stop this turn would be to apply even more pressure on the left rudder pedal, which would
create a wings-level non-turning slip, as will be discussed below in conjunction with figure 1.5. For now,
though, let's consider the correct strategy, which is to keep the slip string centered and apply a bank (to the
left, in this case) to stop the turn. This is shown in figure 1.4. This uses a leftward component of lift 3 paired
with the rightward rudder force. Once again we have a pair of forces with a lever arm between them, i.e. a
pure torque. This lift/rudder pair cancels the thrust/drag pair discussed above.
To reiterate: when engine trouble develops, the first result of the asymmetric thrust is to make the airplane
yaw toward the dead engine. The airplane changes its heading immediately (whereas only later does it
gradually change the direction it is going). That is, a slip angle develops immediately. If you don't deflect the
rudder, the slip angle will grow until the uncoordinated airflow striking the rudder develops enough torque to
141
stop further yawing. This is the basic yaw-axis stability mechanism and the result is that the airplane does not
spin around and around like a Frisbee — it just develops a few degrees of slip angle and then stabilizes.
1.2.5 Perception and Initial Response
If an engine fails suddenly, the initial yaw toward the dead engine is usually quite noticeable. On the other
hand, if it fails gradually, the initial yaw (heading change) may be harder to perceive than you might have
guessed. It is especially hard to perceive if it occurs during a turn — the turn just proceeds a little faster or
slower than normal. The subsequent boat turn may not be super-easy to perceive, either. 4
There are three basic ways to perceive and deal with the slip and yaw.
1. If you happen to have a slip string installed, the procedure is simple. If the string is deflected to one
side, step on the rudder pedal on the opposite side, until the string is centered. The mnemonic is: "Step
away from the string".
2. A less-elegant, less-accurate technique is to use the inclinometer ball. If the ball is deflected to one
side, step on the rudder pedal on the same side. The mnemonic is: "Step on the ball". Center the ball,
then (to establish zero slip, as discussed below) relax the pedal force to let the ball go off center about
one-third to one-half of its width.
3. A third technique (which is really the most common technique) is to roll the wings level and then
apply the rudder as needed to stop the boat turn. The advantage of this procedure is that it can be done
without reference to instruments. The main disadvantage is that it doesn't help you regain or retain
control in a turn. 5 (There are rare situations where even though an engine has failed you might want to
be turning.) Then, once you've got the wings level and the turn stopped, you should establish the optimal
zero-slip condition, by raising the dead engine a few degrees and releasing some of the rudder pressure. 6
At this point, you will find yourself maintaining a rudder deflection and an aileron deflection, both toward
the side with the working engine. Use the rudder deflection (not the bank!) to identify which engine has
failed. The mnemonic is: working foot, working engine; dead foot, dead engine. Specifically, if the right foot
is not being used to deflect the rudder, bend your right knee. Raise that knee an inch or two, pat it a couple of
times, and say "right engine has failed". (More on this later.)
To maintain zero slip, you will need to bank the plane very slightly toward the working engine. The
mnemonic is: raise the dead. This also implies that the inclinometer ball will be slightly displaced toward the
working engine. This correct procedure (figure 1.4) requires slightly more aileron and slightly less rudder
than you would need for wings-level, ball-centered, non-turning, uncoordinated flight (figure 1.5).
Having the slip string centered but the inclinometer ball not centered may seem a bit counterintuitive, so let's
examine the aerodynamics of the situation a little more closely.
The asymmetric thrust produces a yaw-axis torque, which cannot remain unopposed. The rudder is part of
the solution, but remember that while the rudder is producing the desired torque it is also producing a force.
We need the forces to be in balance, as well as the torques.
Suppose you try to maintain zero bank instead of raising the dead. Initially the airplane is not in equilibrium,
because the rudder is producing an unbalanced force toward the dead-engine side. There are then two
possibilities:
1. Suppose the sideways force remains unbalanced. This will cause the airplane to turn. This will be a
wings-level, coordinated turn. I call this a pseudo boat turn. Unlike an ordinary boat turn, the airflow is
coordinated along the fuselage, but unlike a regular turn, the horizontal force is not coming from the
wings.
2. Suppose you push a little harder on the rudder pedal, establishing a slip toward the dead engine. The
ball is centered, the wings are level, and the rate of turn is zero. (Any two of those things implies the
third, regardless of engine status.) The forces are in balance because there is enough uncoordinated
142
airflow over the fuselage to create a sideways force that balances the rudder force. This situation is
shown in figure 1.5.
Figure 1.5 - Engine Out: Wings-Level Nonturning Slip
In this situation, you are using the fuselage as an airfoil. The problem is that the fuselage has a really poor
lift-to-drag ratio. The sideways fuselage lift force is accompanied by a huge drag force, which steals energy
from you. It would be much better to use the wings, as previously discussed in conjunction with figure 1.4.
The proper technique is counterintuitive, because in any normal situation, proper coordination implies that
the rate of turn will be proportional to the amount of bank. With an engine out, though, proper coordination
requires a slight bank when you are not turning.
The amount of bank for a typical airplane can be estimated using the following argument: The lift-to-drag
ratio of the airplane is roughly ten-to-one. In level flight the thrust must therefore be one tenth of the lift. The
lever arm between the wings and the rudder is typically about three times the lever arm between the thrust
and the drag. Since the torques must cancel, the rudder force (and the horizontal component of lift) must be
one third of the thrust, and therefore one thirtieth of the lift. We conclude that the horizontal component of
the lift is one thirtieth of the total lift. One thirtieth of a radian is two degrees — not exactly a huge bank.
To find out exactly how much bank you need to maintain coordinated airflow over the fuselage, it helps to
use a slip string. At a safe altitude, set up for single-engine flight at VYSE. Apply enough rudder pressure so
that the slip string indicates zero slip angle. Bank as required to maintain nonturning flight. Experiment with
slightly greater or lesser rudder pressure, to see what produces the best climb performance.
You will discover that in optimal single-engine flight, the inclinometer ball is not centered, but the slip string
is centered. The airplane is inclined, but it has zero slip angle. Make a note of how much inclination is
indicated by the inclinometer ball; typically it will be off-center by one-half or one-third of its diameter. You
can use this information to set up a good approximation of engine-out coordinated flight during subsequent
flights when you don't have a slip string installed.
The inclinometer ball measures the inclination of the wings relative to the E-down 7 direction. The
inclinometer is sometimes referred to as a slip/skid ball, but that is a misnomer 8 — the slip string (as
discussed in section 1.2.3) provides your only direct information about the slip angle.
Achieving zero slip is the key to optimal climb performance. 9 The idea is to have the airflow aligned with
the fuselage. Centering the inclinometer ball is not what determines performance. Practice with the slip string
until you learn how much inclination is required for a given amount of asymmetric thrust. You may be
wondering whether you can just let go of the ailerons and let the slip-roll coupling roll the airplane into the
optimal bank. That's a clever idea, but it won't quite work. The working engine creates more slipstream over
its wing, producing more lift on that side. You need to deflect the ailerons toward that side to compensate.
1.2.6 Yaw Control at Reduced Speeds
143
So far, we have discussed engine-out climb rate (section 1.2.2) and discussed the value of maintaining
coordinated flight (section 1.2.4). We now begin a discussion of airspeed. As you might imagine, this is
rather important.
So, let's consider what happens when airspeed variations are added to the previous scenario. Let's assume
you start out at cruise airspeed and gradually decelerate. Again, to simplify the discussion, let's assume the
right engine has failed.
The amount of asymmetric thrust does not depend on airspeed; it depends only on the power output of the
engine. In contrast, the amount of force the rudder produces depends on the airspeed squared, and on the
rudder's angle of attack. Therefore as you decelerate you will need progressively more rudder deflection in
order to maintain zero slip. If you do it right, the sideways force developed by the rudder will remain
unchanged, and the bank angle will remain unchanged (for now).
At some point you will run out of rudder deflection. The pedal (or the rudder itself) will hit the stops. You
will be unable to maintain zero slip.
Now, suppose you continue to decelerate beyond this point. As a slip angle develops, the airflow hits the tail
and rudder at an angle. This gives the tail/rudder an angle of attack over and above whatever angle of attack
you created by deflecting the rudder. You are using the slip angle as a substitute for additional rudder
deflection. Up to a point, this higher angle of attack allows the tail/rudder to produce a higher coefficient of
sideways lift, allowing it to produce the required force in spite of the lower airspeed.
In addition to the air hitting the rudder, you now have the uncoordinated airflow hitting the fuselage. You are
relying on the rudder to produce at least 100% of the torque needed to oppose the asymmetric thrust. The air
hitting the fuselage makes a small unhelpful contribution to the torque budget, and (more noticeably)
contributes to the sideways force budget, producing an undesirable boat turn. This boat turn is in addition to
the pseudo boat turn that the rudder is producing, so you will need to increase the bank angle to maintain
nonturning flight.
Obviously there is a limit to this process. If you keep increasing the rudder's angle of attack, at some point
the rudder will stall. Remember, the amount of asymmetric thrust does not depend on airspeed, whereas the
absolute maximum amount of force the rudder can produce depends on the airspeed squared. Therefore, for
any nonzero amount of asymmetric thrust, there must be some airspeed below which the rudder cannot
develop enough torque. At that point there will be an uncontrollable yaw toward the dead engine. The
airplane will spin like a Frisbee.
You might think you could improve the situation by releasing the rudder pedal, thinking this would reduce
the rudder angle of attack. Alas, it won't work. It will just cause the airplane to establish a greater slip angle.
Remember the rudder needs to produce a certain amount of force to oppose the asymmetric thrust, and the
airplane's natural yaw-axis stability will adjust the tail/rudder's angle of attack, trying to create the necessary
force. 10
If the rudder stalls, it will be about as unpleasant as anything you can imagine. There will be a sudden
uncontrollable yawing motion. Because of the yawing motion, the wingtip on the side with the good engine
will have a higher airspeed than the wingtip on the other side. Because of the difference in airspeed (plus the
difference in propwash patterns) the good-side wing will produce much more lift, so you will get an
uncontrollable roll. As the inside wing drops, it will probably stall (since you were already at a low airspeed).
You are now in a spin. There is no guarantee that it will be possible to recover from the spin; multi-engine
aircraft certification regulations do not require spin recoveries.
144
On some planes (such as an Apache, a common trainer) low-speed engine-out performance is limited by the
rudder, as described above. On some other planes (such as a Seneca, another common trainer) you don't need
to worry about the rudder because the wings will stall first. 11 This is not much of an improvement, because a
stall with asymmetric power is also rather likely to result in a spin.
To prevent such nasty things from happening, you need to maintain a safe airspeed. The manufacturer gives
you some guidance in this regard, as is discussed in the following section.
1.2.7 Minimum Control Speed — Definitions
The symbol VMC denotes "minimum control speed". There are at least four different definitions of this term,
including:
I) FAR 23 (the certification requirements for typical general-aviation 12 airplanes) gives a very specific
definition of VMC, namely:
FAR 23.149 Minimum control speed.
(a) VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it
is possible to maintain control of the airplane with that engine still inoperative, and thereafter
maintain straight flight at the same speed with an angle of bank of not more than 5 degrees. The
method used to simulate critical engine failure must represent the most critical mode of powerplant
failure expected in service with respect to controllability.
(b) VMC for takeoff must not exceed 1.2 VS1, where VS1 is determined at the maximum takeoff
weight. VMC must be determined with the most unfavorable weight and center of gravity position
and with the airplane airborne and the ground effect negligible, for the takeoff configuration(s) with(1) Maximum available takeoff power initially on each engine;
(2) The airplane trimmed for takeoff;
(3) Flaps in the takeoff position(s);
(4) Landing gear retracted; and
(5) All propeller controls in the recommended takeoff position throughout.
II) FAR 1 (the "definitions" section) defines VMC as "minimum control speed with the critical engine 13
inoperative". It does not specify any restrictions as to weight, configuration, altitude, et cetera.
III) The FAA Practical Test Standards for the multi-engine rating call for demonstrating "VMC" in a
particular way that emphasizes losing yaw control without stalling the wing or rudder, even though (as
discussed below) for many airplanes VMC (under definition I or II) is limited by wing stall and/or rudder
stall.
IV) In common parlance, pilots apply the term VMC to the airspeed where the airplane (multi-engine or
otherwise) becomes uncontrollable, no matter what the reason, no matter what the configuration, and no
matter whether any engine is inoperative.
Note that none of these definitions require that the airplane exhibit a positive rate of climb at VMC. 14
Also note that during a VMC demonstration, the pilot is not required to optimize the climb rate or to maintain
zero slip — although zero slip is an advantage if it can be achieved.
The VMC number in the Pilot's Operating Handbook is determined according to the FAR 23.149 definition.
This airspeed is marked with a red radial line on the airspeed indicator, and is sometimes called the FAR
23.149 redline airspeed. (There are of course other redlines: at the high end of the airspeed indicator, on the
tachometers, etc.)
145
There are various ways to lose control; whichever happens first determines where the manufacturer sets the
redline:
a) In some airplanes, under some conditions, you can maintain control, even with an engine out, right
down to the point where wing stalls. This is discussed below in conjunction with figure 1.6. A stall with
asymmetric thrust could be rather sudden and nasty.
b) In others (with a smaller rudder, larger wing, and/or higher-thrust engines), there will be conditions
under which the rudder will stall before the wings do, as is discussed below in conjunction with figure
1.8. A rudder stall could be very sudden and very nasty.
c) In yet others (larger rudder area but a shorter tail-boom, so that the rudder is closer to the wings), there
will be situations where neither the wing nor the rudder is stalled, but the boat-turn forces are so large
that it requires more than 5 degrees of bank to counteract them and maintain nonturning flight. The
airplane would be perfectly controllable if the bank were not limited to 5 degrees. Since a bank of 15 or
20 degrees is not particularly dangerous, the 5 degree limitation must be considered arbitrary. If your
airplane, at a given weight and altitude, does run up against this limitation, the resulting "loss of control"
is neither sudden nor nasty. The airplane will just make a gentle boat turn toward the dead engine, as is
discussed below in conjunction with figure 1.7.
Possibility (c) is in some ways attractive, but you have no guarantee that this is what will happen. Rudder
stall depends on slip angle, so you may be wondering why FAR 23.149 should mention a bank angle as
opposed to a slip angle. Bank does not cause slip. 15 If you want to establish any connection between bank
and slip, you must consider at least four factors:
1. bank angle (i.e. the angle between wings and horizon)
2. slip angle (as indicated by the slip string)
3. rate of turn
4. asymmetric thrust
If any three of these are zero, the fourth is guaranteed to be zero. More generally, other things being roughly
equal, given any three of these you can estimate the fourth. The problem is that other things are generally not
equal — depending on weight, airspeed, airplane design, et cetera, five degrees of bank could correspond to a
large slip angle or perhaps no slip angle at all. So this regulation is not 100% logical.
Some people seem to assign a near-religious significance to the "5 degree bank" mentioned in FAR 23.149.
However, the real significance is quite limited:
I. This regulation applies to the manufacturer during certain tests. It does not apply to you in your
ordinary flying. If you have a real engine failure, you are limited only by the laws of aerodynamics.
II. This regulation does not even apply to you during the checkride for a multi-engine rating. In
particular, the FAA Practical Test Standard says you should bank for "best performance and
controllability". Alas, that's inconsistent; best controllability requires a lot more bank than best
performance, and the PTS doesn't tell you how to make the tradeoff.
III. Five degrees is no guarantee of optimum performance. The optimal bank could be five degrees, or
more, or less (usually less).
IV. Five degrees is no guarantee of safety. The maximum bank you can safely use in nonturning engineout flight could be five degrees, or more 16, or less 17.
One thing we learn from this is that you should not use bank angle or anything else as a substitute for proper
airspeed control.
For that matter, airspeed control requires a little thought, too. Perhaps because FAR 23.149 uses words like
"most critical" and "most unfavorable", people commonly assume that it is always possible to control the
airplane at redline airspeed, no matter what. This assumption is wrong — dangerously wrong — in many
airplanes. For example, there are some airplanes where the certified takeoff configuration 18 calls for the flaps
146
to be extended, and the FAR 23.149 redline is essentially equal to the stalling speed in the takeoff
configuration. Then if you operate with the flaps retracted, you will lose control of the airplane at an airspeed
well above redline. 19
Specific procedures for dealing with engine failure are discussed below, in section 1.3.
1.2.8 Effect of Altitude, Weight, etc.
FAR 23 tells us that the airplane, when operated under a particular set of circumstances, can maintain
directional control at redline airspeed. The question is, what happens under other circumstances?
Let's discuss an example. Consider a non-turbocharged airplane for which the handbook calls for flaps
retracted during takeoff. Then, under standard conditions (takeoff configuration, maximum weight, etc.), the
situation is shown in figure 1.6. The single-engine stall speed for the example airplane is shown by a black
vertical line in the middle of the figure. The FAR 23 redline is shown as a bright red tick mark on the
airspeed axis. The manufacturer had to set it a knot or two above the stalling speed, since that is what limits
the low-speed handling for this airplane in this configuration.
Figure 1.6 - Speed & Altitude affect Directional Control (basic)
Also, in this figure, the magenta curve shows the airspeed below which the rudder cannot develop enough
force to oppose the asymmetric thrust. Thirdly, the dotted cyan curve shows the airspeed below which the
boat turn forces are so large that it would require more than 5 degrees of bank to maintain nonturning flight.
Since the example airplane is not turbocharged, as altitude increases there is less thrust available on the good
engine. The required amount of rudder force declines accordingly. This is why the magenta and cyan curves
trend to the left as they go up. Note that in this configuration, for this airplane, rudder performance is not a
limitation — the wing stall is the only relevant limitation.
Now, suppose that several things change:
 You fly at reduced weight, about half of the legal maximum.
 You extend the flaps. 20
 You limit yourself to 3 (not 5) degrees of bank.
147

You limit yourself to less than full rudder deflection.
The new situation is shown in figure 1.7.
Figure 1.7 - More Flaps, Less Weight, etc.
Let's consider what happens under these new circumstances. The reduced weight will lower the stalling
speed. Similarly, extending the flaps lowers the stalling speed. This is indicated by the black line, which
moves to the right as we go from figure 1.6 to figure 1.7.
The amount of torque developed by the engine depends on altitude in the same way as before, and is
unaffected by the weight, flaps, and other variations. The amount of force the rudder can produce is also
unaffected. Therefore the magenta curve is the same in the two figures.
At the reduced weight, less lift is needed for supporting the weight of the airplane. As always, the horizontal
component of lift, at any particular bank angle, is proportional to the weight of the airplane. Therefore, at any
particular bank angle, you have less ability to oppose a boat turn. This is one reason why the cyan dotted
curve moves to the right as we go from figure 1.6 to figure 1.7.
Limiting yourself to less than full rudder deflection does not reduce the amount of torque that must be
produced in order to oppose the asymmetric thrust; it just means that the airplane will establish a slip to
create the necessary force. 21 In this slipping condition, the fuselage produces a boat turn on top of whatever
pseudo boat turn the rudder is producing, so you will need more bank to oppose the turn, and you will run up
against the bank limitation sooner. This is the second reason that the dotted cyan curve (the bank limit)
moves to the right.
And of course, if you limit yourself to a smaller bank, you will run up against the bank limit sooner. This is
the third reason that the cyan curve moves to the right as we go from figure 1.6 to figure 1.7. Conversely, if
you allow yourself a large bank (15 or 20 degrees) you can push the dotted cyan curve very far to the left, as
indicated in figure 1.8.
148
Figure 1.8 - More Bank
Finally, let's consider what happens in different airplanes. For example #2, let's take an airplane where the
wing has a very low stalling speed. For such a plane, figure 1.6 never applies; figure 1.7 (or figure 1.8,
depending on bank angle) applies even at max weight with the flaps retracted.
For example #3, let's go to the opposite extreme and consider an airplane that has somewhat smaller wings.
To compensate, the manufacturer specifies that flaps are to be extended in the certified takeoff configuration.
The result is that the certified performance of the new plane is identical to the performance of example
airplane #1, as shown in figure 1.6. The interesting wrinkle is this: if you fly the new airplane with flaps
retracted, the performance is as shown in figure 1.9. Note the higher wing stall speed. The airplane will
become uncontrollable at an airspeed well above the FAR 23.149 redline.
149
Figure 1.9 - Certified Flaps Not Used
Let's summarize this information into a form that is perhaps more directly useful when you are actually in the
cockpit, planning or performing engine-out maneuvers.
 Maintain a safe airspeed. This speed should be above the wing's stalling speed in the current
configuration and above the FAR 23.149 redline, whichever is higher. Leave yourself a reasonable
margin of safety.
 The best procedure involves establishing zero slip (or minimum slip, if full rudder deflection isn't
enough to establish zero slip), and banking to stop the turn. The amount of bank increases as the
weight decreases; use whatever bank angle does the job. Remember, though, that maintaining a safe
airspeed is more important than getting exactly the right slip angle or bank angle.
 In your multi-engine training, you were probably given the chance to demonstrate "loss of
directional control" under conditions where the "loss" resulted in a gentle boat turn toward the dead
engine. You absolutely must not assume that the airplane will always behave this way. In other
circumstances, you might get a sudden rudder stall or wing stall, either of which could result in a
spin.
 It should be possible to demonstrate a gentle "loss of directional control" at a safe airspeed, as
suggested in figure 1.7. You just have to put sufficiently strict limits on the bank and rudder
deflection. Reduced weight helps, too. Turbocharging makes it easier to perform the demonstration
at a safe altitude.
 If you go exploring speeds below redline, things get dicey. If you allow yourself unlimited 22 bank,
there is no doubt that you can maintain directional control right down to the point where the wing
stalls and/or the rudder stalls. You can get a good estimate 23 of the wing's stalling speed, but I can't
think of a safe way for you to find out whether or not the rudder will stall before the wings. 24 Please
do not try to find this out experimentally!
150
1.2.9 Effect of Center of Mass
We know that we have to pay careful attention to the location of the airplane's center of mass, since it has a
big effect on the angle of attack stability.
This leads us to wonder what effect center-of-mass position has on VMC. There are two possible answers:
1) CM location has no effect whatsoever if you use the unwise wings-level technique depicted in figure
1.5.
2) CM location does matter if you use the recommended procedure depicted in figure 1.4. As the CM (or
more precisely, the center of lift) moves aft, VMC increases.
In both cases, you need to create a torque to oppose the asymmetric thrust. You create it using a pair of
forces with a lever arm between them. One force comes from the rudder.
In case (1), the rudder force is paired with a horizontal force due to air hitting the side of the fuselage. This
fuselage horizontal lift depends on the shape of the airplane, but does not at all depend on the CM location.
There is a deep theorem of physics that says that the torque around one point is the same as a torque around
any other point (provided there are no overall unbalanced forces on the system). In this case, it means that
(unless the airplane is actually turning, i.e. being accelerated sideways), VMC can't depend on center of mass
location.
To understand the basis of this theorem, refer again to figure 1.5. Let's pick two pivot points A and B
somewhere along the rudder/wing lever arm. (You can, if you wish, imagine them to be two possible
locations of the center of mass; the CM is no better or worse than any other pivot point.) When we calculate
the total torque around each pivot point:
 The lever arm from A to the rudder is long, but the lever arm from A to the other horizontal force
is short.
 The lever arm from B to the rudder is short, but the lever arm from B to the other horizontal
force is long.
The total torque around A is exactly the same as the total torque around B. The total torque is the only thing
that affects VMC, and that is the same no matter what pivot point is used.
In case (2), the rudder force is paired with the horizontal component of lift from the wings, tail, et cetera.
This component arises because you are in a slight bank, as illustrated in figure 1.4. The location of this force
depends indirectly on the CM location, according to the following chain of reasoning:
a) The large vertical component of lift must be located very close to the center of mass, to oppose the
force of gravity; otherwise the airplane would be out of equilibrium in pitch.
b) The small horizontal component of lift is located at the same place as the large vertical component.
Here's another way of saying the same thing: the location of the lift vector depends directly on the shape of
the airplane, but you have to adjust the shape of the airplane in order to keep the center of lift located very
close to the center of mass. Note that we are not talking about the lift of the wings alone, but the lift of the
entire airplane including the tail. In the particular example illustrated in figure 1.4, the center of mass is
located rather far forward. The tail has been adjusted to produce a negative amount of lift in order to
maintain equilibrium in pitch. The horizontal component of lift depends directly on this contribution from the
tail, which in turn depends on CM location.
As the center of lift moves aft, the lever arm between it and the rudder gets shorter. This means you need
more rudder deflection and more bank to oppose any given amount of asymmetric thrust.
1.2.10 Effect of Drag (e.g. Landing Gear)
151
To reiterate: in engine-out flight you have two problems: impaired rate of climb, and asymmetric thrust
which can lead to uncontrollable yaw if you're not careful.
You may be thinking that it is possible to counteract the asymmetric thrust using asymmetric drag.
Technically, that's true, but as we shall see, it isn't particularly practical.
About the best imaginable asymmetric drag is shown in figure 1.10. A source of additional drag (a small
parachute) is attached far out on the wing (on the working-engine side). Because it has a long lever arm, a
modest amount of drag force will create a significant amount of yaw-axis torque. This will help you maintain
directional control. Of course, the drag will exacerbate your rate-of-climb problems.
Figure 1.10 - Asymmetric Drag (Useful)
If the parachute is attached at a different point, the results will be different. If it is attached near the working
engine, as shown in figure 1.11, its contribution to the yaw budget will be exactly the same as if you had
throttled back the working engine; added drag is the same as reduced thrust. The effect on climb performance
is also the same as if you had throttled back. Obviously, using the throttle is more convenient and practical
than adding asymmetric drag.
Figure 1.11 - Asymmetric Drag (Useless)
Now, using figure 1.12, we can do a more detailed analysis of how the landing gear contributes to the yawaxis stability and equilibrium. Suppose you are flying due westward.
Figure 1.12 - Extended Landing Gear (Worse than Useless)
First of all, imagine that (unlike the situation shown in the figure) the slip angle is zero. Then the force on the
nose wheel is a pure drag force, that is, a force in the eastward direction. In this case it is parallel to the
airplane's X axis. This contributes nothing to the yaw-axis torque budget, because there is no component of
force perpendicular to the lever-arm.
Next, consider what happens when (as shown in the figure) a slip angle has developed. Once again, the force
on the wheel will be mostly a drag force, that is, an eastward force parallel to the relative wind. You can see
in the figure that since the wheel is no longer directly west of the center of lateral effort, the drag force will
have a component perpendicular to the lever arm, so it will contribute a yaw-axis torque. The torque will
152
grow in proportion to the slip angle. Since the wheel is ahead of the center of lateral effort, this will make a
negative contribution to the yaw-axis stability.
The center of lateral effort is usually quite far aft (since the vertical fin and rudder make a large
contribution). Therefore on nearly all airplanes not only the nose gear but also the main gear are ahead of the
lateral center of effort and make a negative contribution to yaw-axis stability.
As a final refinement, we consider the fact that when the wheel meets the air at an angle (as shown in figure
1.12), it acts a little bit like an airfoil and produces a force perpendicular to the relative wind, i.e. a sideways
lift force. This force grows in proportion to the slip angle and makes another negative contribution to the
yaw-axis stability.
To summarize this section:
 Extending the landing gear always creates drag, which impairs the rate of climb.
 To the extent that the landing gear creates symmetric drag, it contributes nothing to yaw-axis
equilibrium.
 The landing gear typically makes a negative contribution to yaw-axis stability. 25
 Typically the only contribution that is even theoretically helpful comes from the asymmetry of
having one landing gear in the propwash of the working engine. However, this is not a practical
advantage since you could achieve better rate of climb, the same equilibrium, and better stability by
keeping the landing gear retracted and slightly reducing power on the working engine.

Of course, during the descent and landing phases, there are some obvious advantages to extending the
landing gear.
1.2.11 Critical Engine
On typical aircraft, you will notice that the left engine causes more yaw trouble than the right engine does.
This is mainly because of the helical propwash.
Since we are considering a high-power situation well below cruise speed, the helix will be extra-tightly
wound. You will need to hold a certain amount of right rudder just to maintain straight and level, coordinated
flight at that speed, even with both engines running.
When we combine the helical propwash with asymmetric thrust, there are two cases:
 If the right engine quits, and the left one is still producing power, you will need left rudder to
compensate for the asymmetric thrust, but right rudder to compensate for the helical propwash.
The two effects will cancel at least partially.
 If the left engine quits and the right one is still producing power, you will need to hold right
rudder for the asymmetric torque and additional right rudder for the helical propwash. You will
run out of right rudder authority in this case sooner than in the other case.
In such airplanes the left engine is called the critical engine, since it is the one you most regret losing.
Note: Some twins have counter-rotating propellers. (That is, one engine rotates clockwise while the other
rotates counterclockwise.) In that case both engines cause equally much yaw trouble, and either (or neither)
can be considered the critical engine.
P-factor contributes to the torque budget. When you transition from cruise airspeed to VMC, you have to raise
the angle of attack. The wind blowing through the propeller disk at an angle produces P-factor. The P-factor
effect is in the same direction as the helical propwash effect, and negligible in magnitude.
1.3 Engine Out Procedures
153
Engine failure is an emergency. Make sure you know the emergency checklist for your airplane. Not all
airplanes are the same. The following discussion applies to a "generic" airplane, and serves to illustrate some
important concepts, but should not be taken as a substitute for airplane-specific knowledge.
During takeoff, it is important to be able to detect any problems promptly. Early in the takeoff roll, you
should glance at the gauges (RPM, manifold pressure, and fuel flow) to make sure the readings are normal and that both engines are the same. Make sure the airplane "feels" like it is pulling straight, i.e. no unusual
steering effort is required to keep it going straight.
If anything funny happens while there is adequate runway remaining ahead of you, close both throttles
immediately and stop straight ahead. In a high-powered airplane, such as an airliner, there will be a point
where it is not possible to stop on the runway but it is possible to accelerate and fly away safely on one
engine.
In contrast to airliners, typical light twins use a smaller fraction of the runway for a normal takeoff, yet have
worse single-engine performance. As a consequence, there is a time even after liftoff when it is better to
close the throttles and re-land on the remaining runway. Indeed, even if the remaining runway is not quite
enough, you might want to land on it: Suppose that because of density altitude or whatever, your aircraft has
poor single-engine climb performance. You will sustain vastly less damage if you land and slide off the end
of the runway at low speed, rather than making an unsuccessful attempt to climb out on one engine.
In many light twins, the climb performance is decent with the landing gear retracted but very poor with it
extended. Therefore a common rule is the following: when there is no more useful runway ahead, retract the
gear. If an engine fails before that point, you know you are committed to landing; if it fails after that point,
you know you are committed to climbing.
1.3.1 Procedure: Low Altitude
Once you are airborne and assured of single-engine climb performance, the following checklist applies to our
generic airplane at low altitudes: three things, five things, four things. Specifically:
 Three things: airspeed, ball and needle.
 Five things: mixtures, propellers, throttles, gear, flaps.
 Four things: identify, verify, feather, secure.
Now let's spell each item out in more detail, for the case where your initial speed is above VMC:
 Three things: airspeed, ball, and needle. That is, pitch to maintain best-climb speed. Then the
easiest thing to do is apply enough rudder pressure to center the ball. "Step on the ball." This
involves more rudder pressure than you need to establish zero slip, but at this stage of the game
you are in a hurry and centering the ball is a rough-and-ready approximation. With the ball
centered, nonturning flight will require a slight bank toward the working engine. (Wings-level
non-turning flight is really overdoing it. It involves a slip toward the dead engine, which puts an
unnecessary burden on the rudder and degrades climb performance.)
 Five things: mixture controls forward (rich), propeller controls forward (fine pitch), throttles
forward (maximum allowable power), gear retracted, flaps retracted.
 At this point you might want to check airspeed, ball, and needle again. The airplane has probably
decelerated quite a bit, so you may need to make a pitch adjustment and retrim.
 Four things: identify, verify, feather, secure. Let's suppose the right engine has failed.
 Identify: raise your right knee (dead foot, dead engine) and say aloud, "the right engine
has failed".
 Verify: retard the right throttle. There should be no change in the situation. If you retard
the wrong throttle you will notice immediately; push it forward again, go back to step 1
(airspeed, ball, and needle), and try again.
 Feather: grab the correct propeller control, pull it back a little ways and listen to make
154

sure you've got the right one, then pull it all the way into the feather position. (If this is a
simulated emergency, just pull it back half an inch or so and tell your instructor that you
are simulating the feather.)
 Secure: when the engine has stopped spinning, shut off its mixture control, its fuel
supply, its boost pumps, its alternator, its magnetos, et cetera. Close its cowl flaps and
open the cowl flaps on the working engine.
Finally, check airspeed, ball, and needle again. Make sure you are trimmed for best-climb speed.
Establish zero slip by applying somewhat less rudder pressure than is necessary to center the
ball; let the ball go off-center by one-third to one-half of its diameter. Use the rudder trim to hold
this arrangement. In this condition, nonturning flight will require banking a few degrees toward
the good engine: "raise the dead".
Here are the same items again, for the where you have a fair bit of initial altitude, but your initial speed is
below VMC: 26
 Three things: airspeed, ball, and needle. You urgently need to dive to regain VMC. As always,
"step on the ball" to get the airflow approximately coordinated. You may be unable to establish
zero slip, even with full rudder deflection, in which case you should apply full rudder and let the
airplane establish whatever slip is necessary to oppose the asymmetric thrust. To establish
nonturning flight, the wings should be almost horizontal, with the dead engine raised slightly.
 If you are in danger of losing directional control, you will have to reduce power on the good
engine. Skip the mixture and propeller controls for now. Retract the gear and flaps.
 Five things: After you have gotten back to VMC, advance both throttles, both propeller controls,
and both mixture controls. Confirm gear retracted and flaps retracted.
 Continue accelerating to best-climb speed. This will probably require cashing in additional
altitude.
 Four things: identify, verify, feather, secure — the same as before.
In the case where your initial altitude and initial airspeed are both rather low, it may not be possible to regain
VMC by diving. In this case the procedure is rather simple: you have to close the throttles and make an
immediate landing.
1.3.2 Procedure: Higher Altitude
Finally, here is the procedure for the case where you have a reasonable airspeed and a reasonable altitude,
say 1000 feet AGL or more. You should not be in any big hurry to feather the offending engine. If the
problem is minor, restarting will be a lot easier if the engine is not feathered. The checklist should be:
 Three things: airspeed, ball, and needle.
 Five things: mixtures, propellers, throttles, gear, flaps.
 Four things: identify, verify, debug, think.
Take a systematic approach to debugging. Start somewhere on the panel and then check everything you come
to, systematically.
It doesn't hurt to be logical, but remember that in an actual emergency, you will be much less logical than
you normally are. Unless it is obvious what the problem is, check everything, in order. Don't just check the
things that come to mind. Systematic habits are more likely to stay with you.
After you've checked everything once, then try applying logic. What was the last thing you fiddled with
before the failure? Did you just shut off the fuel boost pumps? Maybe you should switch them back on; look
at the fuel pressure... or did you miss the boost pumps and turn off the magnetos instead? Did you just switch
from the inboard to the outboard tanks? Maybe you should switch back, or switch to crossfeed.
155
Remember that you may be unable to climb or even maintain altitude on one engine. See section 1.2.2 for a
discussion of this.
1.3.3 Airspeed Control
The airspeed that gives the best single-engine rate of climb is referred to as VYSE. The value of VYSE for
standard conditions (max weight, sea level, etc.) is marked on the airspeed indicator by a blue radial line, and
is commonly called blue line airspeed.
If an engine fails, you should (except in certain special situations) maintain a speed at or above VYSE.
Maintain thine airspeed lest the ground arise and smite thee.
One exception to the foregoing rule: If you need altitude to avoid an obstacle, you'll be better off at VXSE
(best angle of climb) as opposed to VYSE (best rate of climb). In typical trainers, the single-engine
performance is so anemic that VXSE will be only slightly slower than VYSE, for reasons illustrated in figure
7.6. Indeed, if you are above the single-engine absolute ceiling, the climb rate is negative and VXSE is
slightly faster than VYSE.
Another exception: The optimal airspeed on final approach is typically less than VYSE. You're not
climbing, so you don't need to worry about climb performance (unless you need to go around, as
discussed in section 1.3.4).
Another relevant airspeed is the minimum control airspeed, VMC. As discussed in section 1.2.7, you could get
into big trouble if the airspeed gets too much below VMC. At any speed above VMC you should apply full
power on the good engine and accelerate to best-climb speed. Don't be shy about diving to get to best-climb
speed; remember the airplane might not be able to climb or accelerate at all at lower speeds.
At speeds below VMC, you will be forced to use less than full power on the good engine, to keep the yaw
from getting out of hand while you accelerate to VMC. Losing an engine at an airspeed below VMC is a really
nasty situation which (for obvious reasons) most people don't practice during training. To recover, you have
to partially close the throttle on the good engine, which takes a lot of willpower. You don't have much time
to think. Then you have to dive, cashing in quite a lot of altitude to get the needed airspeed. The usual
procedure calls for accelerating to VMC plus a few knots, to give yourself a little margin, before returning the
good engine to full power.
1.3.4 Engine-Out Go-Arounds
The first thing to be said about engine-out go-arounds is that you should make every possible effort to make
sure that you do not ever need to perform one. The most common reason for a go-around is that you are
about to land long and run off the end of the runway. Therefore, if at all possible, fly to somewhere that has a
really long runway before attempting any engine-out landing.
The second thing to be said is that for typical airplanes there is a certain height above the ground — often a
surprisingly great height — below which an engine-out go-around is simply not possible. The reason for this
is simple: approach speed is below best-climb speed. If you try to climb out at low airspeed, the rate of climb
may well be negative. In order to accelerate from approach speed to climb speed, you will need to cash in
quite a lot of altitude. You will also consume time (and altitude) while you retract the landing gear, et cetera.
In a Seneca, the decision to go around must be made above 400 feet AGL; below that altitude, you are going
to touch down. If the runway is obstructed, land on the taxiway, or the infield, or whatever.
1.3.5 Low-speed engine-out demonstrations
There are several key ideas I want my students to know about low-speed engine-out performance, including:
1. Starting from moderate speeds, as you slow down you will need more and more rudder to maintain
coordinated flight. This is the coordinated regime. The amount of bank needed to maintain nonturning
156
flight is basically constant.
2. There comes a point where you run out of rudder authority and cannot maintain coordinated flight. As
the speed decreases further, the slip angle automatically increases, and more boat turn gets added to the
pseudo boat turn. This is the uncoordinated regime. The bank angle must increase as airspeed decreases
if you want to maintain nonturning flight.
3. You can maintain control down to VMC (in the takeoff configuration). 27
4. If you persist in engine-out flight down to sufficiently low airspeed, at some point the wings and/or
rudder will stall and you will be very sorry.
5. If you are below VMC, you should reduce power on the good engine, dive to regain VMC, and then reopen the throttle on the good engine.
6. If you are below VYSE (except in special situations, such final approach) you should dive to regain
VYSE.
The aircraft manufacturer is supposed to specify a minimum safe speed for intentional engine cuts, denoted
VSSE, which is typically quite a bit higher than VMC.
To demonstrate these key ideas, you should start in the takeoff configuration at a speed at or above VSSE.
Then cut one engine, and gradually decelerate. This will demonstrate idea #1 immediately. If you are worried
about reaching VMC before you have a chance to demonstrate idea #2, you can artificially limit the available
rudder deflection, perhaps by blocking the pedal with the toe of your other shoe. We do not wish to
demonstrate idea #4. After demonstrating flight slightly above VMC (idea #3), return to VYSE (idea #6) and
then resume normal flight.
To demonstrate a portion of idea #5, we use a separate maneuver. Starting with both engines at idle, perform
a power-off stall. Recover to VMC, then using only one engine, recover to VYSE.
The FAA commercial pilot multi-engine practical test standard ("PTS") contains a "task" called "ENGINE
INOPERATIVE - LOSS OF DIRECTIONAL CONTROL DEMONSTRATION". The requirements are a bit
confusing. For one thing, the PTS speaks of banking "for best performance and controllability" but doesn't
say how to trade off performance versus controllability. Best climb performance typically requires less bank
than best ultra-low-speed controllability.
Among many examiners, the traditions concerning this task are as follows:
A. Start at a safe altitude and safe airspeed. The PTS calls for VYSE plus ten knots.
B. The PTS calls for flaps set for takeoff. However, there are some planes (such as a Seneca) where the
certified takeoff checklist calls for zero flaps, and where redline is essentially equal to the stalling speed.
In such planes you can lower the stalling speed by extending the flaps, which will make the
demonstration safer and easier. Most examiners are happy to permit this. Call it "short field" takeoff
configuration if you like. In other planes (such as an Apache) where the stalling speed is already well
below redline, don't bother extending the flaps.
C. Reduce power on one engine to idle. Do not actually stop or feather the engine.
D. Depress the rudder to establish zero slip. This gives best performance.
E. Bank to establish nonturning flight. This will be a very shallow bank.
F. Block the rudder motion to ensure that you run out of rudder before the airspeed gets close to the edge
of the envelope. Stay away from redline and wing-stall speed, whichever is higher. The PTS calls for
staying 20 knots above the wing-stall speed. 28
157
G. Gradually decelerate.
H. After you run out of rudder deflection, the unwritten rule is that you should not increase the bank.
That means the airplane will start to turn. The turn is your signal that it is time to begin the recovery
phase. You are not being asked to demonstrate key idea #2.
Before the checkride, you should discuss these unwritten rules with your examiner, to make sure you are
both singing the same tune.
The airspeed limit is needed to ensure safety. The artificial limits on rudder deflection and bank are needed
so that you can demonstrate a nice gentle boat turn, by pretending to run out of control authority; otherwise
the airplane would be controllable at all safe airspeeds and there would be nothing to demonstrate.
Note that in everyday (non-checkride) flight, if you run out of rudder authority at a speed above redline (and
if you are sure you want to be flying so slowly) you would just smoothly enter the uncoordinated regime and
increase the bank.
You should not do demonstrations the way FAR 23.149 seems to suggest:
 Do not suddenly shut down one engine at a low airspeed. Shut it down at or above VSSE and then
decelerate. (Alternatively, I suppose it would be safe to fly below VSSE and gradually reduce
power on one engine, but I can't think of a reason why you would want to.)
 Do not explore low-speed performance at low altitude. The practical test standard calls for a
minimum of 3000 feet AGL.
Full-blown FAR 23 VMC determinations should be left to professional test pilots. For that matter, not even
test pilots dare to experiment with loss of control at low altitude. They are not crazy; they experiment at a
series of safe altitudes and then extrapolate.
158
Footnotes
1 A single-engine aircraft is required (by FAR 23.49) to have a stalling speed of 61 knots or less, and
commonly it is quite a bit less. This is important for safety in case of a forced landing. In contrast, a twin
with sufficiently good engine-out performance is exempt from this restriction. The theory is that a twin that
can climb on one engine should never need to make an off-airport landing.
2 We won't discuss aircraft that have centerline thrust, e.g. the Cessna 337 Mixmaster.
3 This means total lift, including the contributions of the wings, horizontal tail, et cetera. The center of lift
will be located quite close to the center of mass.
4 The effects are reduced if the working engine is developing less power (because of small engine size, high
altitude, and/or reduced throttle setting), the airspeed is high, and the rudder is large. Conversely, in a twin
with a small rudder, a large engine, full power, and a low airspeed, a sudden failure will definitely get your
attention.
5 If you forget to roll the wings level before using the rudder to stop the heading change, you could easily
find yourself stepping on the wrong rudder. For instance, if you are in a turn to the right and the left engine
fails, you might be tempted to stop the turn by stepping on the left (wrong!) rudder.
6 To know how much bank and/or how much inclinometer ball deflection corresponds to zero slip, you can
(a) recall from your training flights what configuration corresponds to best performance, (b) recall from
flights with a slip string what configuration corresponds to zero slip, or (c) let the inclinometer ball go offcenter by half its width, which is usually "close enough" to the right answer.
8 The confusion is understandable, since asymmetric thrust is about the only way you can maintain an
inclination without being in a slip.
9 ... or cruise performance, for that matter — engine-out or otherwise. You may be wondering whether you
can just let go of the ailerons and let the slip-roll coupling roll the airplane into the optimal bank. Nice idea,
but no such luck. The working engine creates more slipstream over its wing, producing more lift on that side.
You need to deflect the ailerons toward that side to compensate.
10 In fact, an undeflected rudder produces a less stall-resistant shape, which will probably stall at a higher
airspeed.
11 If redline (as defined in the following section) is down near the bottom of the green arc, it is a good guess
that wing stall is what limits the airplane's low-speed controllability. Conversely, if redline is much higher
than the bottom of the green arc, you can guess that rudder stall is what limits the low-speed controllability
(unless the redline is artificially high because of the arbitrary 5 degree bank limit in FAR 23.149).
12 A very similar regulation, FAR 25.149, applies to transport-category aircraft (e.g. airliners).
14 If the airplane weights more than 6000 pounds, FAR 23.66 requires the airplane to be able to climb with
one engine inoperative, at an airspeed "equal to that achieved at 50 feet" after takeoff. Even this does not
require climb at VMC.
15 This statement comes as a shock to some people, but it is true, to a good approximation. Here's a little
additional explanation:
a) Slip angle is in fact perpendicular to the bank angle. Slip angle can be observed and semiquantitatively measured by a slip string.
b) A wings-level boat turn involves a slip angle with zero bank. An ordinary coordinated turn involves a
bank angle with zero slip.
c) In a twin with an engine out, you can have a turn with no bank and no slip, or a slip with no bank and
no turn, or (preferably) a bank with no turn and no slip.
Significant causes of slip include:
· rudder deflection,
· asymmetric thrust, and
· tight turns (via the long-tail-slip effect).
Significant causes of turn include:
· bank, and
· slip (via boat turn).
16 There are many airplanes that are quite nicely behaved even under conditions that require more than 5
degrees of bank in order to maintain non-turning engine-out flight.
159
17 That's right: there is no guarantee that 5 degrees is safe. It is commonly assumed that "the manufacturer
must have tested a 5 degree bank because that is the maximum allowed". But in fact, best control might be
achieved at 2 or 3 degrees, and there is no reason to assume that the manufacturer ever tried more than that.
Remember, in non-slipping flight the bank required is quite modest (and independent of airspeed), and there
is not much that the manufacturer can achieve by slipping that could not be better achieved by more rudder
deflection.
There is nothing in FAR 23.149 or anywhere else that guarantees the airplane is well behaved at the
"official" 5-degree bank angle. In particular, there is no guarantee that limiting yourself to 5 degrees you
will always get aerodynamic warning (in the form of a nice, gentle boat turn) before you get a nasty
rudder stall or wing stall. If you want to demonstrate a gentle warning, you might need to limit yourself
to much less than 5 degrees.
18 This means the takeoff configuration as specified in the Pilot's Operating Handbook or Airplane Flight
Manual. Remember that these documents are legally part of the airplane. You can't have a certified VMC
without a certified takeoff checklist.
19 In this example, we are assuming that wing stall (not rudder stall) is what limits low-speed handling.
20 This option is available to us because, for this airplane, the certified takeoff configuration did not call for
flaps to be extended.
21 If there were an unbalanced torque, the airplane would not only turn, it would accelerate around the yaw
axis.
22 We are talking about rather modest bank angles, perhaps 15 or 20 degrees, that would not get you into
trouble in other circumstances.
23 It may be a good idea to check the wing's stalling speed by performing a stall with both engines at zero
thrust. The zero-engine stalling speed won't be quite the same as the one-engine stalling speed, but it should
be a useful estimate.
24 I have done calculations that indicate that for certain light trainers, the wings will almost always stall
before the rudder, but you absolutely should not assume that this is true for all airplanes in all circumstances.
25 One could imagine designing an airplane with the landing gear so far aft that they were behind the lateral
center of effort, in which case they would increase yaw-axis stability.
26 It's a little hard to see how this situation could arise in the course of normal flying. However, (a) such a
situation is sometimes created as part of a training exercise, and (b) it could arise if the pilot mishandles an
engine-out situation, squandering the initial airspeed.
27 In other configurations, you can maintain control down to VMC or VS, whichever is higher.
28 In airplanes where VMC is at or near VS, VS + 20 may seem like a generous or even excessive margin of
safety. In other airplanes, however, VS + 20 is not nearly enough. You need to be careful, since there are
plenty of airplanes where VS + 20 is near (or even below) VMC. A better criterion might be to stay above VS +
10 and above redline + 10, whichever is higher.
160