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:
Fuel is simultaneously jettisoned only from the trim and the center tanks.
Fuel is simultaneously jettisoned from the trim, inner and the center tanks.
Once refueling is finished, the END light flashes first and then stays on.
Once refueling is finished, the END light stays on.
With tanks nearly empty, time for refueling all the tanks of the aircraft is approximately:
Refueling can be accomplished:
Refueling Control Panel - The HI LVL light comes on blue, when:
Automatic refueling ensures that:
In case of Fuel Center Pumps fault:
The Airbus A340 fuel system:
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There are two fuel pumps in each collector cell. They are normally selected On and:
In normal operation, engines are always fed from:
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.
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.
In normal operation, the automatic control of CG is ended:
FUEL FEED WITH ALL ENGINES FLAME OUT (ELEC EMER CONFIG) - When the speed goes below _____ kt, or when LAND RECOVERY is selected ON, all MAIN and STBY pumps are lost.
Electrical power requirements for refueling are:
In case of loss of both Fuel Control Monitoring Computers (FCMCs):
In normal conditions, the automatic control of CG is starting:
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.
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The normal fuel JETTISON is stopped when:
Maintenance panel - The END light flashes when:
