Fuel System Flashcards
Which side supplies the APU with fuel?
The APU is supplied by engine No.1.
What are the suction valves?
The suction valves are held closed by fuel tank pressure created by the tank pumps. They are located in the inner tank. In an electrical failure, they remain open as the pressure within the tanks fails and the engines will be able to be gravity fed.
Describe the fuel recirculating system…
Fuel from the HP fuel valve is diverted through the heat exchanger of the IDG. Heat from the oil within the IDG is radiated through the fuel in the exchanger which in turn heats the fuel in the tanks. Fuel is then routed via the HP fuel feed and sent back to the outer tanks.
How is centre tank fuel prioritised?
Centre tank fuel pumps deliver fuel at a higher pressure than the fuel pumps of the inner tanks. Because of this, when the centre tank pumps are on, the centre tank will drain before the inner tanks.
Why is centre tank fuel prohibited for take off?
If the centre tank fuel was used during take off, any fuel returned to the outer tanks from the recirculating system would cause the tank surge vent to spill the excess fuel overboard.
Can you refill on battery power only?
Yes as there is a switch on the refuelling panel to enable this to happen.
What are fuel jet pumps?
There is 1 jet pump in each inner tank and the function is to draw fuel from the centre tank to the inner tank. This is done by creating a vacuum that pulls fuel through the centre tank transfer valves.
