In normal conditions, the automatic control of CG is starting:
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 Airbus A340 fuel system:
In case of "ALL ENGINES FLAME OUT":
In case of Fuel Center Pumps fault:
Maintenance panel - The END light flashes when:
There are two fuel pumps in each collector cell. They are normally selected On and:
Magnetic level indicators are fitted in the lower surfaces of the center and wing tanks to allow the manual measurement of each tank's fuel quantity.
In normal operation, engines are always fed from:
With tanks nearly empty, time for refueling all the tanks of the aircraft is approximately:
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Refueling Control Panel - The HI LVL light comes on blue, when:
In normal operation, the automatic control of CG is ended:
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.
Electrical power requirements for refueling are:
The wings have inner and outer tanks. Each inner tank contains two collector cells that:
When a tank fuel temperature is displayed amber:
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.
Fuel is simultaneously jettisoned only from the trim and the center tanks.
Fuel is simultaneously jettisoned from the trim, inner and the center tanks.
After refueling to maximum tank capacity, fuel can expand by:
As long as FUEL JETTISON p/b are selected ON:
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Refueling can be accomplished:
Once refueling is finished, the END light flashes first and then stays on.
Once refueling is finished, the END light stays on.