The wings have inner and outer tanks. Each inner tank contains two collector cells that:
After refueling to maximum tank capacity, fuel can expand by:
Electrical power requirements for refueling are:
In normal operation, the automatic control of CG is ended:
Inner Tank Pumps - During normal operation, all main pumps run. If a main pump fails, or is switched off, then the standby pump of that inner tank runs. With the crossfeed valves open, one pump is capable of supplying all four engines in cruise.
In case of Fuel Center Pumps fault:
When a tank fuel temperature is displayed amber:
There are two fuel pumps in each collector cell. They are normally selected On and:
The normal fuel JETTISON is stopped when:
With tanks nearly empty, time for refueling all the tanks of the aircraft is approximately:
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In case of loss of both Fuel Control Monitoring Computers (FCMCs):
Maintenance panel - The END light flashes when:
Refueling can be accomplished:
The fuel level sensing data is independent of the fuel quantity indication, therefore even in the case of fuel system erroneous computation, the fuel level warnings are still valid.
X-FEED valves 1 and 2 open in the event of aft transfer from the inner tanks.
X-FEED valves 2 and 3 open in the event of aft transfer from the inner tanks.
Refueling Control Panel - The HI LVL light comes on blue, when:
FAULT lights up on both CTR Tank P/Bs when:
The trim tank transfer system controls the aircraft's Center of Gravity (CG). The system either transfers fuel to the trim tank (aft transfer) or from the trim tank (forward transfer).
This movement of fuel changes the aircraft's CG. When the aircraft is in cruise, the system optimizes the CG position to increase fuel economy by reducing drag. Normal operation is automatic, but the crew can manually select a forward fuel transfer. The Fuel Control and Monitoring Computer (FCMC) calculates the aircraft's CG and compares it to a target value. This target depends on the aircraft's actual weight. Based on this calculation, the FCMC determines the quantity of fuel to be moved aft or forward in flight.
The fuel system is controlled by:
In normal operation, engines are always fed from:
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In case of "ALL ENGINES FLAME OUT":
As long as FUEL JETTISON p/b are selected ON:
The Airbus A340 fuel system:
Once refueling is finished, the END light flashes first and then stays on.
Once refueling is finished, the END light stays on.
Automatic refueling ensures that:
The A340 fuel system inner tanks:
Fuel is simultaneously jettisoned only from the trim and the center tanks.
Fuel is simultaneously jettisoned from the trim, inner and the center tanks.