OPERATIONS MANUAL

Fuel System
Stabilizer Tank Operation:
If the stabilizer tank contains less than 3000 kg (6600 lb) before engine start, the stabilizer
tank pumps must remain off on the ground and through the entire flight. If the stabilizer tank
contains at least 3000 kg (6600 lb) before engine start, stabilizer tank pump operation will be
allowed when the aircraft has reached the cruise altitude. During climb, the stabilizer tank
pumps must remain off. In cruise, the FSMCs will activate the stabilizer tank pumps when the
associated switches are set to ON and the center tank has decreased to 36500 kg (80000 lb).
Stabilizer tank pump operation in cruise:
EICAS quantity indication EICAS message Required crew action
More than 1600 kg (3600 lb) >FUEL PMP STB L Set left pump switch to ON
More than 1000 kg (2300 lb) >FUEL PMP STB R Set right pump switch to ON
Less than 1200 kg (2600 lb) >FUEL LO STAB L Set left pump switch to OFF
Less than 600 kg (1300 lb) >FUEL LO STAB R Set right pump switch to OFF
When the EICAS quantity indication is passing 600 kg (1300 lb), the true quantity is already
in a range between 200 kg (500 lb) and zero.
Wing Tank Operation:
Stage Required crew action Result
Before engine start
and all tanks full.
Main tank 2 or 3
quantity decreased
to 18100 kg
(40000 lb).
Outboard main tank
quantities are equal to
or less than inboard
main tank quantities.
EICAS message:
FUEL TANK/ENG.
Set all valve switches,
main pump switches,
and main tank O/J
pump switches to ON.
When flaps are extended:
FSMCs close crossfeed valves 2 & 3.
O/J pumps in main tanks 2 & 3 supply
engines 2 & 3; main tank pumps 1 & 4
supply engines 1 & 4.
When flaps are retracted:
FSMCs open crossfeed valves 2 & 3.
Center tank pumps supply all engines.
- FSMCs activate transfer from
reserve tanks 2 & 3 to associated
main tanks, and start center tank
scavenging.
Confirm tank
quantities.
Set main tank O/J
pump switches to OFF.
Set valve switches
1 & 4 to OFF.
Main tank pumps provide fuel
to their associated engines until
engine shutdown.
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