There are 3 fuel tanks
Left and right main tanks in wings, center in fuselage.
Center tank vents to both wings, main tanks vent to surge tanks on same side.
Fuel capacities?
787-8
37,319 lbs. in each wing
148,740 lbs. in center tank
223,378 lbs. total fuel
787-9, 787-10
36,984 lbs. in each wing
149,678 lbs. in center tank
223,646 lbs. total fuel
These values based on fuel density 6.7 lbs./gallon
Fuel balance is automatically commanded off for one of the following:
Fuel is balanced.
Jettison system is active.
FUEL DISAGREE message is displayed.
FUEL QTY LOW message is displayed.
The aircraft is on the ground and either engine is running
The expanded FUEL QTY display appears for any of the following:
Crossfeed valve is open
One or more fuel tank qty indicators inoperative
The FUEL IN CENTER alert message is displayed (center tank qty is amber)
The FUEL QTY LOW alert message is displayed (low main tank qty is amber)
The FUEL LOW CENTER alert message is displayed (low center tank qty is amber)
The FUEL FLOW ENG L alert message is displayed.
The FUEL IMBALANCE alert message is displayed.
The aircraft is on the ground and both engines are off.
The balance system is active.
The balance system is selected on and the fuel is already balanced.
The INSUFFICIENT FUEL alert message is displayed (total fuel quantity is amber).
Fuel pumps description summary
Each tank has 2 AC powered pumps
There is one DC motor driven pump in the left main tank. Supplies the APU when AC power not available and APU is selected ON
The center tank pumps are called override / jettison pumps. They operate at higher output pressure so that center fuel is used first.
Any one main tank pump can supply adequate fuel to operate one engine under all thrust conditions
Pumps can be automatically load shed with insufficient power. PRESS light will illuminate and load shed indicated on fuel synoptic
FUEL CROSSFEED amber EICAS message
Valve does not agree with switch position. Amber VALVE light also illuminates within switch
FUEL BALANCE system
Can be used in any phase of flight, even on ground with APU and engines shut down
If balance system is ON and fails, amber EICAS FUEL BALANCE SYS is displayed, and amber FAULT displays within switch
Fuel balance is inhibited for any of the following reasons:
Refueling, defueling, or there is a ground transfer of fuel using refueling panel.
Prior to engine start and the APU is off
The fuel balance system has failed.
A center tank pump is on.
On the ground and one or both engines running.
Inflight and the fuel jettison system is active
FUEL DISAGREE or FUEL QUANTITY LOW message shows.
FUEL JETTISON nozzle switch selected on:
Opens the respective jettison nozzle valve if selected open inflight
If jettison ARM switch is armed, the nozzle switch also opens the main tank defuel / isolation valves, and center tank jettison isolation valves
At least 8700lbs of fuel remains in each main tank after jettison complete
FUEL JETT NOZZLE L/R advisory message
Jettison nozzle not in commanded position
FUEL JETTISON SYS caution message
Fault has occurred (fault light also on within switch), or the jettison system is inoperative
FUEL TO REMAIN selector
When in, ARMING the jettison system will default to the fuel value for max landing weight
When pulled out a different value can be selected
Suction feed
Each engine can draw fuel from its corresponding main tank through a suction feed line that bypasses the pumps
As airplane climbs, dissolved air is released from the fuel into the tank due to decrease in air pressure. As a result, at high altitude, thrust deterioration may occur. Eventually this depletes at cruise altitude - this depletion time depends on the altitude, fuel temperature, and type of fuel.
Fuel pump low pressure light illuminated indicates:
Fuel pump output pressure is low (for the main tank switches).
Fuel pump output pressure is low with the pump selected on (center tank pump switches). This illumination is inhibited with the center pump switches if they are selected off.
FUEL BALANCE SYS advisory:
One of these occurs:
- The fuel balance system is failed.
- A center tank pump is on.
- On the ground and one or both engines are running.
- Inflight and the fuel jettison system is active, or the FUEL DISAGREE or FUEL QTY LOW message is displayed.
FUEL UNUSABLE CTR advisory message
Center tank fuel is unusable due to faults in one or more of the following:
- Center tank pumps
- Crossfeed valve
- Center tank scavenge system.
- Fuel balance system.
- Fuel quantity indicating system.
