Version 2.0, 6 June 2011
Stage 1, Module 2
Copyright © 2011 Ted Dudley
Which airplane are you flying?
 Hit the esc key
 Click on “Slide Show”
 Click on “Custom Slide
Show”
 Select your aircraft
Airframe
Airframe: Fuselage
 The central body of an airplane
 Designed to accommodate crew, passengers, and
cargo
 Provides the structural connection for the wings
and tail assembly
 Two general types of construction:


Traditional skin over a frame
Composite materials
Airframe: Fuselage Construction
Truss (Piper J-3 Cub)
Airframe: Fuselage Construction
Monocoque (RV-7,
Boeing 787)
Modern composite
aircraft often use a
monocoque structure
Semi-monocoque
(Cessna 150, 172)
Easy to build using
aluminum
Airframe: Wings
 Airfoils attached to each side of the fuselage
 The main lifting surfaces that support the airplane in




flight
Many types depending on performance requirements
Can be mounted high, middle, or low on fuselage
Can be single, double, or more: monoplane, biplane,
triplane…
May be supported by one or more struts
Airframe: Wings
Airframe: Empennage
 The airplane’s tail
 Contains fixed surfaces…
 Vertical stabilizer
 Horizontal stabilizer
 …and movable surfaces
 Rudder
 Elevator
 Trim tabs
Airframe: Empennage
 A stabilator is a movable combined horizontal
stabilizer and elevator
 Contains an antiservo tab for stability and trim
Airframe: Flight Controls
 Flight controls in your training aircraft will have
direct mechanical linkages to the yoke/stick
 Larger, more complex aircraft may have
hydromechanical actuation or electronic/hydraulic
(fly by wire) actuation
Airframe: Flight Controls
 Primary flight controls
 Elevator
 Aileron
 Rudder
 Secondary flight controls
 Flaps
 Trim
 Leading edge devices (if any)
 Spoilers (if any)
 Ground adjustable tabs (if any)
Elevators
Ailerons
Rudder
Flaps
 Effectively increase the
camber and sometimes
area of the wing
 In small airplanes, may
be mechanically or
electrically actuated
 Larger airplanes
usually hydraulically
actuated
Trim
 Used to relieve the pilot of the need to maintain
constant pressure on the flight controls
 Usually consist of flight deck controls and small
hinged devices attached to the trailing edge of one or
more of the primary flight control surfaces (trim
tabs)
Trim
 Your training aircraft only has elevator trim, not
aileron or rudder trim
 Actuated by turning trim wheel
 Equipped with an index and mark
for setting proper takeoff trim
Ground Adjustable Tab
 Small piece of aluminum on rudder; can be bent to
proper displacement on the ground
 Set by trial and error for coordinated flight at cruise
speed
 Don’t mess with it!
Airframe: Landing Gear
 The principal support of the airplane when parked,
taxiing, taking off, or landing
 Most commonly use wheels, but airplanes can also
be equipped with floats or skis
 Three wheels


Two main wheels , usually equipped with brakes
Third wheel positioned either at the front or rear of the
airplane
 Landing gear with a rear mounted wheel is called
conventional landing gear; such airplanes are called
tailwheel airplanes or taildraggers
Powerplant
 Usually includes both the engine and the propeller
 Primary function of the engine is to provide the
power to turn the propeller
 Also…



Generates electrical power
Provides a vacuum source for some flight instruments
In most single-engine airplanes, provides a source of heat for
the pilot and passengers
Powerplant
 Engine is covered by a
cowling, which


streamlines the flow of air
around the engine
Helps cool the engine by
ducting air around the
cylinders
Engine
 Your training aircraft has a reciprocating, spark
ignition, air-cooled, four-stroke engine
 Four or six horizontally opposed cylinders
24
1
2
3
4
Intake
Compression
Power
Exhaust
Ignition System
 Two spark plugs in each cylinder ignite the
compressed fuel-air mixture to provide power
 Ignition system components:




Magnetos
Spark plugs
High-tension leads (British for high voltage wires)
Ignition switch
Ignition System
Ignition System
 Faraday’s Law says if you move an electrical
conductor in a magnetic field, an electrical current
will be induced in the conductor
 Magnetos are permanent magnet electrical
generators – if you turn the shaft on the mag, you
will get current flow

The mag is mechanically connected to the engine, so if the
engine turns, you get electrical current
 High-tension leads and mechanical gearing get the
electricity to the right spark plug at the right time
Ignition Switch
 Usually operated with a key
 Positions





OFF
Right mag only
Left mag only
BOTH mags on
START (spring-loaded back to BOTH like a car starter)
 Mags always produce current if the engine turns
 Ignition switch only connects/disconnects circuits
 A fault in the switch could result in a closed circuit (the
spark plug will fire) in any switch position
 Spark plug firing makes the engine run
Important Safety Tip
 ALWAYS treat the propeller as if the engine
will start running any time you touch it!
 You may assume the propeller will cleanly remove
any part of your body that gets in its way
Starter
 Direct-cranking electric starter, which is a small
motor that turns the engine’s flywheel via a gear
 System consists of a battery, wiring, switches, and
solenoids (fancy switches) to operate the starter and
a starter motor
 The gear automatically engages and disengages the
flywheel when operated
Another Important Safety Tip
 Always be sure the prop arc is clear before turning
the starter!
 You can’t see most of the prop’s arc, so yell “Clear”
loud enough and wait long enough so the guy
disconnecting the tow bar can get out of the way
Exhaust System
 Vents the burned combustion gases overboard via
 Exhaust piping attached to the cylinders
 A muffler and a muffler shroud (a chamber around the
muffler)
 A single exhaust stack to the atmosphere
 Provides cabin heat and windscreen defrost
Cabin Heat/Defrost
 Outside air is drawn into a cabin air inlet and is
ducted through the muffler shroud
 The muffler is heated by the exiting exhaust gases
and, in turn, heats the air around the muffler
 This heated air is then ducted to the cabin for heat
and defrost applications
Carbon Monoxide
 Exhaust gases contain large amounts of carbon
monoxide (CO), which is odorless and colorless
 Carbon monoxide is deadly and quick acting
 There is a CO detector in the cabin
 If the spot turns dark…


Cabin heat – closed
Ventilate the cockpit as much as
possible
Carburetor
Air intake
The carburetor
mixes fuel and air
Venturi
Fuel
Throttle
Fuel air
mixture to
engine
• “Rich” means relatively more fuel mixed with air
• “Lean” means relatively less fuel mixed with air
• A lean mixture runs hotter
than a rich mixture!
Accelerator Pump
 When the throttle is rapidly opened, airflow through
the carburetor increases immediately, faster than the
fuel flow rate can increase
 This transient oversupply of air causes a lean mixture,
which can make the engine misfire
 This is remedied by the use of a small pump which,
when mechanically actuated by the throttle linkage,
forces a small amount of gasoline into the carburetor
throat
 Accelerator pump can also be used to prime the engine
prior to start, although we will not use it for that
Idling System
 Carburetor mixture and airflow can be adjusted to
maintain a minimum idle RPM with throttle closed
 Adjustable only by maintenance
 Engine should idle smoothly at an RPM below 900
on the ground
Mixture Control
 Carburetor is normally calibrated at sea-level
pressure with the mixture control set in the FULL
RICH position
 As altitude increases, the density of air entering the
carburetor decreases, while the density of the fuel
remains the same
 This creates a progressively richer mixture, which
can result in engine roughness and an appreciable
loss of power
 To maintain the correct fuel/air mixture, the mixture
must be leaned at altitude using the mixture control
Abnormal Combustion
 Two kinds:
 Detonation
 Preignition
 May occur simultaneously
 One may cause the other
 Using the recommended grade of fuel and operating
the engine within its proper temperature, pressure,
and RPM ranges reduce the chance of detonation or
preignition
Detonation
 During normal combustion, the fuel/air mixture
burns in a very controlled and predictable manner
 Detonation is an uncontrolled, explosive ignition of
the fuel/air mixture within the cylinder’s combustion
chamber
 Causes excessive temperatures
and pressures which, if not
corrected, can quickly lead to
engine damage
Detonation Causes
Too low fuel grade
Mixture too lean
Excessive engine wear
High engine temperature
Preignition
 Occurs when the fuel/air mixture ignites prior to the
engine’s normal ignition event
 Premature burning is usually caused by a residual hot
spot in the combustion chamber, often created by



A small carbon deposit on a spark plug
A cracked spark plug insulator
Other damage in the cylinder that causes a part to heat
sufficiently to ignite the fuel/air charge
 Can also lead to engine damage
Preignition Causes
Incandescent areas
in cylinder
Carbon or lead
deposits
Engine Icing Problems
 Fuel ice
 Impact ice
 Carburetor (throttle) ice
Fuel Ice
 At very low temperatures, free water in the fuel tanks
and lines may freeze
 Below about zero Fahrenheit, ice crystals may
become large enough to clog fuel supply systems
 Fuel additives can help with this
Impact Ice
 When flying through visible moisture at temperatures
near or below freezing, ice may form on the forward
surfaces of the aircraft
 This ice may restrict or even close off the engine air
inlet
Carburetor Ice
 Occurs due to the effect of fuel vaporization and the
decrease in air pressure in the venturi, which causes
a sharp temperature drop in the carburetor
 If water vapor in the air condenses when the
carburetor temperature is at or below freezing, ice
may form on internal surfaces of the carburetor
 This restricts the flow of the fuel/air mixture and
reduces power
 If enough ice builds up, the engine may cease to
operate
Carburetor Ice
Air intake
Venturi
Carburetor ice
Throttle
Fuel air
mixture to
engine
Restriction
Carburetor Ice
 Carburetor ice is most likely to occur when
temperatures are below 70 °F and the relative
humidity is above 80 percent
 Due to the sudden cooling that takes place in the
carburetor, icing can occur even with temperatures
as high as 100 °F and humidity as low as 50 percent
Carburetor Heat
 An anti-icing system that preheats the air before it
reaches the carburetor
 Intended to keep the fuel/air mixture above the
freezing temperature to prevent the formation of
carburetor ice
 Can be used to melt ice that has already formed in
the carburetor if the accumulation is not too great,
but using carburetor heat as a preventative measure
is the better option
 Can be used as an alternate air source if the intake
filter clogs with impact ice or any other obstruction
Carburetor Heat
Exhaust
Manifold
Carb Heat
Intake
Muffler
Shroud
Carb Heat
Duct
Exhaust
Stack
Carb
Carburetor Heat
 A carb temperature gauge may be installed
 Needle in the yellow arc means temperature
conducive to carb icing
 Any time the engine runs rough,


Pull FULL carb heat
Never use partial carb heat
 If engine roughness was due to carb icing
 RPM will decrease;
 Followed by a gradual increase in RPM as the ice melts
Carburetor Heat
 Carb icing is more likely at low power settings
 Use carb heat in flight any time the RPM is below the
green arc
 Carb heat use causes up to 15 percent decrease in
engine power
 Carb heat should not be used when full power is
required (e.g., during takeoff or stall recovery)
 Engine air is not filtered when carb heat is in use, so
make sure it’s off on the ground
Fuel Injection
 Instead of using a carburetor, fuel is injected directly
into the cylinders, just ahead of the intake valve
 But not in your airplane
Air from intake
manifold
Fuel line
Fuel
injector
Fuel System
 Transfers fuel from the fuel truck to the carburetor
 Consists of
 Fuel tanks and fill port(s)
 Fuel vents and overflow drain
 Fuel selector valve
 Sumps, strainer for taking fuel samples
 Fuel primer
 Possibly fuel pump and pressure gauge (normally on low-wing
aircraft)
 Fuel gauges
Normally electrically powered
 Only required to be accurate when reading “empty”
 So always visually check tanks

Fuel System
 Avgas is dyed for identification
 You’ll only see 100LL around here
 A colorless fuel sample is a very bad thing
 Always check your fuel for proper color and water or
sediment contamination

Dispose of fuel samples properly
Fuel System
 Gravity feed – typical
on high-wing aircraft
Fuel System
 Fuel pump – typical on
low-wing aircraft
Fuel System
 One 19.5 gallon fuel tank




in each wing
1.5 gallons unusable in
each wing tank
Total 36 gallons of usable
fuel
Gravity fed
Fuel selector with four
positions: OFF, LEFT,
RIGHT, BOTH
49R, 93L
Fuel System
 One 21.5 gallon fuel tank in




each wing
1.5 gallons unusable in each
wing tank
Total 40 gallons of usable
fuel
Gravity fed
Fuel selector with four
positions: OFF, LEFT,
RIGHT, BOTH
8ZD
Fuel System
 One 13 gallon fuel tank in




each wing
1.75 gallons unusable in each
wing tank
Total 22.5 gallons of usable
fuel
Gravity fed
Fuel selector with two
positions: OFF, ON
43T
Oil System
 Performs several important functions:
 Lubricates the engine’s moving parts
 Cools the engine by reducing friction
 Removes heat from the cylinders
 Provides a seal between the cylinder walls and pistons
 Carries away contaminants
 Oil should be changed at least every 50 hours
 Ensure proper oil level prior to each flight
 Add oil at less than 7 quarts
 Do not operate at less than 6 quarts
49R, 93L
Oil System
 Performs several important functions:
 Lubricates the engine’s moving parts
 Cools the engine by reducing friction
 Removes heat from the cylinders
 Provides a seal between the cylinder walls and pistons
 Carries away contaminants
 Oil should be changed at least every 50 hours
 Ensure proper oil level prior to each flight
 Add oil at less than 6 quarts
 Do not operate at less than 4 quarts
8ZD
Oil System
 Performs several important functions:
 Lubricates the engine’s moving parts
 Cools the engine by reducing friction
 Removes heat from the cylinders
 Provides a seal between the cylinder walls and pistons
 Carries away contaminants
 Oil should be changed at least every 25 hours
 Ensure proper oil level prior to each flight
 Add oil at less than 5 quarts
 Do not operate at less than 4 quarts
43T
Oil System
Cooling System
 Air-cooled engine
 Cooling is less effective at
slow speeds and high
power settings
 Oil temp gauge gives an
indirect indication of
engine cooling
Cooling System
 Some aircraft have a cylinder head temperature
gauge
 If engine temperature is excessive, consider landing
 Any of the following may reduce engine temperature:



Increasing airspeed
Enriching the mixture
Reducing power
Electrical System
 14-volt direct current (DC) system powers electrical
accessories, including flaps
 Consists of
 Alternator
 12-volt battery
 Master switch
 Bus bar, fuses, and circuit breakers
 Voltage regulator
 Ammeter
 Associated electrical wiring
49R, 93L
Electrical System
 Split bus system
 Primary bus for most stuff
 Electronic bus for radios

Electronic bus automatically
disconnected while starter is
engaged
 Single push-pull master
switch
 Engine-driven alternator
keeps battery charged
 System powers the ignition
switch, not the spark plugs

They get power from mags
49R, 93L
Electrical System
 Ammeter shows battery charge or discharge


Needle leaning left – battery discharging
Needle leaning right – battery charging
 Fuses and circuit breakers protect circuits
and help prevent electrical fires


Fuse which can’t be accessed in flight (for clock)
Circuit breakers (CBs) on most other things

If a CB pops in flight, you may notice only if you notice its associated
electrical device non-functional
 reset it once after allowing 2 minutes to cool
 If it pops again, do without that electrical
device. Resetting repeatedly could start a fire!
 In either case, contact maintenance after flight
49R, 93L
Electrical System
 28-volt direct current (DC) system powers electrical
accessories, including flaps
 Consists of
 Alternator
 24-volt battery
 Split master switch: one side for battery, the other for alternator
 Bus bar, fuses, and circuit breakers
 Voltage regulator
 Ammeter
 Avionics power switch
 Over-voltage sensor and warning light
 Associated electrical wiring
8ZD
Electrical System
 Split bus system


Primary bus for most stuff
Switched avionics bus for radios

Avionics power must be OFF when
turning master on or for engine start
 Engine-driven alternator keeps
battery charged
 System powers the ignition
switch, not the spark plugs

They get power from mags
 Overvoltage sensor turns off
alternator and illuminates a red
light when sensing overvoltage
8ZD
Electrical System
 Ammeter shows battery charge or discharge


Needle leaning left – battery discharging
Needle leaning right – battery charging
 Fuses and circuit breakers protect circuits
and help prevent electrical fires


Fuse which can’t be accessed in flight (for clock)
Circuit breakers (CBs) on most other things

If a CB pops in flight, you may notice only if you notice its associated
electrical device non-functional
 reset it once after allowing 2 minutes to cool
 If it pops again, do without that electrical
device. Resetting repeatedly could start a fire!
 Avionics power switch also functions as a CB
 In either case, contact maintenance after
flight
8ZD
Electrical System
 14-volt direct current (DC) system powers electrical
accessories
 Consists of
 Alternator
 12-volt battery
 Master switch
 Bus bar, fuses, and circuit breakers
 Voltage regulator
 Generator warning light
 Associated electrical wiring
43T
Electrical System
 Engine-driven alternator keeps battery charged
 Red generator warning light comes on if battery is discharging
 System powers the ignition switch, not the spark
plugs

They get power from mags
43T
Electrical System
 Fuses and circuit breakers protect circuits and help
prevent electrical fires


Fuses on some things
Circuit breakers (CBs) on most other things

If a CB pops in flight, you may notice only if you notice its
associated electrical device non-functional
 reset it once after allowing 2 minutes to cool
 If it pops again, do without that electrical device. Resetting
repeatedly could start a fire!
 In either case, contact maintenance after flight
43T
Vacuum System
 Consists of
 Engine-driven vacuum pump
 Relief valve
 Air filter
 Vacuum gauge calibrated in inches of mercury
 Tubing necessary to complete the connections
 Power source for attitude indicator and directional
gyro/heading indicator

These are your primary instruments for flying in clouds

We’ll be using these instruments, but avoiding all clouds
Vacuum System