FUEL SYSTEM Flashcards
Fuel Quantity
Total 42 : 4500 / 72: 5000 Kg
Feeder tank: 160 kg
Surge tank: 100 l
FUEL SYSTEM
ELECTRICAL FUEL PUMP OFF
FUEL SYSTEM
STARTING PROCEDURE
ENGINE SHUT DOWN WITH ELECTRICAL PUMP RUNNING
Both fuel engine electrical pumps push buttons are pressed IN and green RUN lights illuminate.
The electrical pumps are energized and begin to supply fuel to engines.
The FEED LO PR amber light extinguishes when the pressure is > 4 psi in the pipe.
At the same time, the feeder jet pump is activated by the electrical pump output pressure, to supply and maintain the feeder tank full.
FUEL SYSTEM
NORMAL PROCEDURE
After engine start, the flow, from return line of the HMU, opens the Motive Flow Valve, in order to supply the Engine Feed Jet Pump.
The Engine Feed Jet Pump begins to operate by driving fuel from the feeder tank.
At the same time, it supplies the Feeder Jet Pump.
When the Engine Feed Jet Pump outlet pressure reaches 8.5 PSI, the electrical pump is de-energized after 30s time delay. In normal operation of the fuel system, the engine is only supplied by the Engine Feed Jet Pump and the electrical pump is de-energized.
Conditions to energize the electrical pump (See details on pages hereafter)
– Cross feed operation
– Engine Feed Jet Pump outlet pressure drops below 5 psi
– Low Level
FUEL
CROSS FEED PROCEDURE
Cross feed valve could be used to supply an engine from the opposite tank.
The cross feed is not used to tranfer fuel from one tank to the other tank.
With the Xfeed valve push button pressed IN, the valve opens, green flow bar is horizontal. Both electrical pump are energized.
FUEL SYSTEM
CROSS FEED PROCEDURE CONT’D
By selecting OFF the corresponding PUMP push button, the electrical pump is de-energized and the motive flow valve is supplied to close. The engine is fed from the opposite tank.
FUEL SYSTEM
ENGINE FEED JET PUMP LOW PRESSURE
In the event of engine feed jet pump failure, the pressure switch (<5 psi) provides electrical pump running control which ensures fuel supply to the engine.
The electrical pump delivers the necessary flow rate for engine consumption.
Fuel LO LVL
When the low level is triggered in one tank, its electrical pump is automatically activated.
Two low level cases:
– LO LVL with fuel quantity indicator < 160 kg → Low level of remaining fuel in the tank.
– LO LVL with fuel quantity indicator > 160 kg → Feeder tank not full due to a failure of the feeder jet pump.
In this condition, the fuel is transfered from the main tank to the feeder tank through the flappers.
