Fuel System Flashcards
Where is fuel stored ? How is it fed to the engines
3 Tanks 1 in each wing and 1 centre tank.
The centre tank contains two electrically driven fuel pumps which transfer fuel to the collector tanks. The collector tank contains two electrically driven fuel pumps which supply fuel to engines and APU
Where are the collector tanks
Each wing tank consists of an outer tank and a collector tank
What means of fuel ventilation is there
Tank ventilation to ambient air takes place via vent valves or, if blocked, via sniffle valves
How is fuel transferred from the centre tank
Fuel from the centre tank is transferred to the wing tanks by two electrically driven
centre tank pumps
What happens during transfer when a collector tank is full
When a collector tank is full, the excess fuel flows into the outer tank
What happens during transfer if one pump fails? Both pumps
With one pump operating a normally closed transfer valve will open to allow fuel transfer from the operating pump to both collector tanks. If both pumps are inoperative the centre tank contents become unusable. Fuel transfer is automatically controlled when either centre tank pump is switched ON and the AUTO FEED push button is blank.
When does the transfer take place
Fuel is transferred when the engine fuel flow exceeds 1135 kg/hr. (2500 lbs. /hr.) and/or when the fuel quantity of both wing tanks is below a predetermined value
What is the purpose of the cross feed system
The supply lines from the collector tanks to the engines are interconnected by a cross feed line which is normally closed by two cross feed valves. These valves are controlled by the X-FEED push button. The cross feed system allows any engine to be fed from either or both collector tanks. To balance the fuel in the good tank
Where is quantity displayed
The aircraft is equipped with a fuel quantity indication system that consists of a fuel quantity totalizer and separate displays for each wing tank and the centre tank at the FUEL panel.
When does a fuel asymmetry alert appear and disappear
A fuel asymmetry alert will be presented if the difference between the contents of the wing tanks is more than 350kg (770 lbs.). The alert will disappear when the difference in wing tank contents is reduced to below approximately 250kg (600 lbs.)
What other means of measuring fuel quantity is there
The fuel quantity of each wing tank can also be measured on the ground with three magnetic fuel-level indicators mounted underwing. One indicator is also installed in the centre tank, when aircraft equipped with integral centre wing tank
How is the aircraft normally refueled
Pressure re and defueling of the aircraft is accomplished through a single point fuelling system and is controlled from the fuel service panel.
Is gravity refueling possible
The wing tanks can also be fuelled by gravity through the over wing fuelling points.
When would a collector tank low level alert be presented
Jet pump failure
What is the procedure for cross feeding to the correct imbalance
Crossfeed on then fuel pump off
