B737NG
BRIEFINGS
LOSS OF BOTH ENGINE DRIVEN GENERATORS
What you should see on the
Electrical Panel
•
First indication of loss of both engine driven generators is a
MASTER CAUTION illumination with multiple caution lights
and instruments warnings flags on both panels.
[including TRANSFER BUS OFF, SOURCE OFF and GEN
OFF BUS]
•
Caution! Don’t be confused with « loss of both engines ».
To discriminate between the two
situations, advance the thrust levers
and check if engines respond.
Check also if ENG FAIL is displayed
on both EGT indicators.
•
STBY AC BUS and STBY DC BUS automatically switch to their back-up source upon loss of both
engine driven generators. The STANDBY PWR OFF amber light should not be illuminated!
If you see this light illuminated, the first check-list to be started [before the LOSS OF BOTH
ENGINE DRIVEN GENERATORS] is the STANDBY POWER OFF NNC
STANDBY PWR OFF Light
Illuminated (amber) – one or more of the
following busses are unpowered:
• AC standby bus
• DC standby bus
• Battery bus.
QRH
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 1
B737NG
BRIEFINGS
What is the purpose of the STANDBY POWER Switch?
AUTO (guarded position)
In flight, or on the ground, and AC transfer busses powered:
• AC standby bus is powered by AC transfer bus 1
• DC standby bus is powered by TR1, TR2 and TR3
In flight, or on the ground, loss of all AC power
• AC standby bus is powered by battery through static inverter
• DC standby bus is powered by battery
• Battery bus is powered by battery.
OFF (center position)
• STANDBY PWR OFF light illuminates
• AC standby bus, static inverter, and DC standby
bus are not powered.
BAT (unguarded position)
• AC standby bus is powered by battery through static inverter
• DC standby bus and battery bus are powered directly by battery.
When placing the Standby Power Switch to BAT, the STANDBY PWR OFF amber light
should extinguish.
CAUTION! If the STANDBY PWR OFF light is illuminated after a loss
of both engine driven generators
1) Unpowered AC Standby bus means, at least (non-exhaustive list):
- ATC 1 [XPDFR] INOP
- Right Igniters INOP [No more igniters!]
- ADF No.1 INOP
- GPS No.1 INOP [No more GPS!]
- Fuel Quantity indicators INOP
2) Unpowered DC Standby bus means, at least (non-exhaustive list):
- VHF1 INOP [No more VHF!]
- Engine No.1 thrust reverser INOP
- NAV1 INOP [No more NAV capability!]
- EFIS Control panel INOP
- Stick shaker captain INOP
3) Unpowered Battery bus means, at least (non-exhaustive list):
- Engine 1 & 2 start lever Chan A+B INOP
- Engine 1 & 2 Fire Protection INOP
- Fuel Engine 1 & 2 HPSOV INOP
- Landing Gear Air Ground relays + Alternate Extend solenoid INOP
- Standby attitude indicator INOP
- N1 & EGT INOP, etc, etc
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 2
B737NG
BRIEFINGS
Example: B737-800 [Dual battery equipped]
BUS TRANSFER Switch
- AUTO (guarded position)
BTBs operate automatically to maintain power
to AC transfer busses from any operating
generator or external power
[DC cross tie relay automatically provides
normal or isolated operation
as required].
- OFF
Isolates AC transfer bus 1 from AC transfer bus
2 if one IDG is supplying power to both AC
transfer busses
[DC cross tie relay opens to isolate DC bus 1
from DC bus 2].
The breaker is behind the FO’s seat.
The SPCU (Standby Power Control Unit) uses the
battery & standby power switch position to control
the distribution of AC & DC standby power.
Heading – Enter through CDU
FMC/CDU POS INIT page .......................... Select
Enter the correct heading into the CDU scratch pad then
press lineselect key 5R. Verify entered heading appears
on line 5R. Select HDG on the IRS display selector and
verify that the entered heading is displayed on the
navigation displays.
Heading – Enter through ISDU
IRS display selector ........................................HDG
Press the H key to initiate a heading entry.
Key–in present magnetic heading. Press the ENT key
(the cue lights extinguish). Observe proper heading
displayed on the navigation displays.
Declare MAYDAY
[Note: With only one generator available,
declare PAN-PAN and land at the nearest
suitable airport].
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 3
B737NG
BRIEFINGS
Takeoff, Approach and Landing on Standby Power
Boeing says that « the probability of a total and unrecoverable AC power failure is remote ». Because
of system design, a NNC for accomplishing an approach & landing on standby power is not required.
•
Complete all applicable NNCs and approach preparations.
•
Refer to Volume 2, Chapter 6 of your Boeing FCOM for a list of significant equipment powered by
standby power.
The following list identifies the significant equipment that operates when the main battery and the
auxiliary battery are the only source of electrical power (all generators INOP) on
aircraft:
SECTION
Airplane General
Air Systems
Anti-Ice
Communications
Electrical
Engines & APU
Fire Protection
OPERATIVE ITEMS
• Standby compass light
• White dome lights
• Emergency instrument flood lights
• Flight crew oxygen
• Passenger oxygen
• Standby forward airstair interior/exterior operation
• A/C pack valves
• BLEED TRIP OFF lights
• Manual pressurization control
• Atitude warning horn
• PACK lights
• Captain’s pitot probe heat
• Flight interphone system
• Service interphone system
• Passenger address system
• VHF No. 1
• STANDBY POWER OFF light
• Upper display unit (N1, N2, fuel flow, EGT, fuel
quantity, oil pressure, oil temperature, oil quantity)
• Thrust reversers
• Starter valves
• Right igniters
• APU operation (start attempts not recommended
above 25,000 feet)
• APU and engine fire extinguisher bottles
• APU and engine fire detection system
• Cargo fire extinguisher bottle
Flight Controls
• TE and LE Flaps
Flight Instruments
• Captain’s outboard display unit with PFD
• Captain’s inboard display unit with ND
• Clocks
• Left EFIS control panel
• Standby instruments (RMI, stdby airspeed/altimeter,
stdby attitude indicator, stdby magnetic compass
REMARKS
- Automatic Passenger Oxygen
Control & Release INOP (manual
control is available)
- AUTO & ALTN pressurization
modes are INOP. Below 10,000 ft
(or at lower if altitude) select MAN
and open outflow valve to land
unpressurized
- All TE and LE Flaps indications are
INOP. TE & LE Flaps are available
but without asymmetry protection
(based on the pointers of the Flap
indicator which is itself INOP):
extend flaps step by step and
monitor control wheel for any roll.
- Electrical trim is INOP
- Takeoff: Keep T/O flap setting +
maneuvering speed: flap position
indicator is INOP and flap retraction
schedule is not available
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 4
B737NG
BRIEFINGS
[Continuing]
SECTION
Flight Management
Navigation
Fuel
Hydraulic Power
Landing Gear
Warnings
OPERATIVE ITEMS
[EI-DPF through EI-DPV]
• left FMC
[EI-CSA through EI-DPE]
• FMC
--------------------------------------------------------------------• Left CDU
• Heading/track indications
• VHF NAV No. 1
• ILS No. 1
• Left IRS
• Left GPS
• Marker beacon
• ADF No. 1
• DME No. 1
• Crossfeed valve
• Engine fuel shutoff valves
• Spar fuel shutoff valve
• FUEL VALVE CLOSED lights
• Fuel quantity indicators
• Engine hydraulic shutoff valves
• Standby rudder shutoff valves
• Inboard antiskid system
• ANTISKID INOP light
• Parking brake
• Air/ground system
• Landing gear indicator lights
• Stall warning system
• Aural warnings
• Master caution light Recall
REMARKS
- All fuel pumps are INOP: possible
thrust deterioration or engine
flameout at high altitude!
- Fuel contained in Center tank is no
longer available. (check possible
overweight landing)
- Outboard Antiskid INOP [verify
QRH Performance Inflight Advisory
Information for landing distance!]
- Autobrakes INOP
Basic Equipment Operating – Captain Instrument Panel [
aircraft]
The standby power system utilizes the battery as a source of power to supply the below depicted
flight instruments. All of the Captain’s instruments that are powered by standby power are integrally
lighted on standby power
Left Hand Seat (LHS)
pilot is always PF
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 5
B737NG
BRIEFINGS
•
After takeoff, climb to MSA and stay below 10,000 ASL because aircraft is unpressurized!
•
Be careful: No altitude alert for level off!
•
Check MCP: in certain circumstances Reversion to Standby power may cause the Barometric
setting to revert to Standard. Altitude window could have switched to 50.000ft, MCP speed window
to 110kt. Reset as necessary!
•
Ask for vectors if available.
•
Consider CAT I landing only to land back.
•
If both primary attitude displays are INOP (see QRH), the IRS drifts like a conventional gyro: you
need to update a heading entry every 15 minutes and before commencing the approach. Before
entering the magnetic compass reading, correct the value for deviation thru the compass deviation
card.
Always take your time for this process! PNF should have a good crosscheck with the PF before
entering and executing any value into the ISDU or the CDU. Any wrong value entered by mistake
could result in a space disorientation!
•
Should your remaining FMC be INOP, remember that you will have to set reference airspeed bugs
for approach via the SPD REF knob [see Boeing Supplementary Procedures / Flight Instruments,
displays]:
Speed reference selector (outer) ....................................................WT
[Default weight of 32,000 kgs / 70,000 lbs is displayed].
Speed reference selector (inner) .................. Set current gross weight
[Flaps up maneuver speed bug is displayed].
Speed reference selector (outer) ................................................VREF
[Default speed of 80 knots is displayed].
Speed reference selector (inner) ...............................Set VREF speed
The green VREF bug and white VREF +20 bug are shown when a speed greater
than 80 knots is set.
Note: If V1 or VR is selected in flight, INVALID ENTRY is displayed.
To set the spare bug, if desired:
Speed reference selector (outer) ........................................ Spare bug
[Default speed of 60 knots is displayed].
Speed reference selector (inner) ................................................... Set
[Set speed as desired].
Speed reference selector (outer) ...................................................SET
[Digital readout is removed].
•
Fly the approach on speed.
•
Because outboard anti-skid is not available, and with the higher approach speed, any excess
speed is undesirable.
•
Bear in mind that auto speedbrake is INOP upon landing: extend speedbrake manually.
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 6
B737NG
BRIEFINGS
•
Never abort your takeoff above 80 kt in case of loss of both engine driven generators because:
- Antiskid is INOP
- RTO mode is INOP
- Speedbrakes automatic extension is INOP
•
Do not retract flaps after take off if possible (no severe icing conditions): flap position indicator is
INOP and flap retraction schedule is not available
•
In cruise, do not stay above 25,000 ft if the actual MORA permits it. Again, remember that APU
start attempts are not recommended above 25,000 feet. Because of the loss of the engine fuel
pumps, thrust deterioration or engine flameout is also a critical factor.
•
Avoid Multiple start attempts which would deplete the battery and would reduce standby power
capacity: battery endurance would be definitely affected
•
Avoid LNAV & VNAV selection before complete FMC pages check!
Copyright 2007 - SmartCockpit.com
Version 01 (Feb.07)
B737 NG BRIEFINGS
Page 7