Fuel System Flashcards
Tanks
1 integral tank/ wing
Fuel distribution
Under normal conditions each tank supplies the equidistant engine through a collector tank located at the inboard of each tank.
APU
Is supplied by the engine’s 2 collector tank.
Is fed my electrical pumps when engines are not running or by the primary ejector pumps when the engines are running.
How are engines being fed
By primary injector pumps one each side which are driven by primary ejector pumps which are driven by high pressure motive fuel pumps.
AC pumps
They are to assure engine feed in the event of a primary ejector pump failure plus it provides a source of pressurized fuel supply to the engines and APU for ground and in-flight start.
Refueling and Defueling
Refueling and Defueling is made from the right wing but only Refueling can be done from the Gravity Refuel Adapter on the top of each wing.
It is designed to provide continuous pressurized fuel to the engines without pilot intervention.
Wing Tanks include
Surge tank to collect fuel during uncoordinated manœuvres or wing down
Collector tank to ensure continuous fuel feed.
Fuel distribution is made from outboards and into the collector tank.
Baffle and Flapper check valves on each wing to prevent fuel escaping from the collector tank and from entering the surge tank.
Tank vent system
Keeps differential pressure btwn the tank and ambient
Prevents fuel spillage
The vents are separated lines for each wing into the surge tank.
Drain valves
Due to gravity, water will be collected from collectors and wing tanks and drained through the drain valves
Fuel indication system
Electrical fuel quantity
Mechanical fuel quantity
Fuel temperature
Fuel low level indication (independent probe from the fuel quantity indication probe)
Type of determining fuel quantity
AC capacitance type electrical fuel indicating subsystem. In case this fails the back up system is operated by means of magnetic level indicators and allows the aircraft to be dispatched
Temp indication
Green when temp is -37< celsius
Amber when temp -37> celsius
Amber dashes when there is a fault
Fuel status indications
White when on Standby
Green when in operation
Amber dashes when there is a fault
Fuel warnings
When fuel drops <300kg a low level warning will be displayed on EICAS.
Important Notes
- in case of loss of the transfer system followed by the EICAS warning message, fuel quantity indication monitoring during the flight is achieved through the EICAS or the MFD fuels System synoptic page.
*Engine flameout is possible due to starvation if the airplane is submitted to attitudes 15degrees up/down, uncoordinated manœuvres or negative Gs