FUEL Flashcards
The wing feed tanks are designed to maintain approx ___min supply of fuel for each engine.
30 mins
What compensates for the tank pressure increasing/decreasing due to altitude changes?
climb/dive valves
What characteristics make the fuel tank crash-worthy?
- self-sealing protection against 0.50 caliber AP ballistic impacts
- wing tanks are 100% self-sealing
- sponson fuel cells are fully self sealing , except for the top surface and the top 2/3 of the outboard surface
- wing aux fuel cells are self-sealing on the lower 1/3
- break away fittings on the fuel tank lines prevent fuel from pouring out of the tank in the event of a crash landing
The fuel supply system is a ______, ______, ______-type system.
crash-worthy, fully automatic, suction-type system
8 Major functions of the FMUs:
- measure fuel quantity
- manage fuel burn sequence
- manage ground/aerial refueling, de-fueling, and fuel dump
- monitor fuel system health and isolate component faults
- communicate system status GRDP
- communicate system status to the integrated avionics system
- communicate fuel quantity status to the SFD
- communicate low engine/gearbox oil levels to the GRDP and the maintenance flight summary page
What is the fuel burn sequence?
- aft sponson tank
- mid and forward MAT (if installed)
- wing auxiliary tanks
- forward sponson tanks
What tanks have suction lift pumps?
feed tanks
What tanks have boost pumps?
- sponson tanks
- wing aux tanks
- MATs (if installed)
When do the boost pumps come on when TRUMP BOOST - ON or AUTO is selected?
(4ish instances)
- feed tank quantity drops below 565lbs
- low level sensor is dry for 5 seconds
- during fuel dump
- two sponson boost pumps operate during gravity refueling and refuel manifold purge
When does FEED TANK LOW come on and when does it turn off.
- FEED TANK LOW comes on at 520 lbs or the low level sensors are dry for 45 seconds
- FEED TANK LOW turns off at 585 lbs are the low level sensor indicates wet for 60 secs after feed tanks are considered recovered
The XFER valve is unavailable (slashed) during the following fuel system operations:
- Ground refuel/de-fuel
- PFBIT
- PSOV (Pump shut off valve) IN TEST
- FMU/AERIAL REFUEL
- FUEL DUMP
- TPUMP BOOST - AUTO
- engine or APU not running
T/F: The FMU follows the same burn sequence for single engine operation as it would for both engines running.
TRUE
During single engine operation, commanding TRUMP BOOST ______ and selecting XFER valve to ______ will do what and why?
ON ; OPEN
mitigate uneven fuel burn to minimize any lateral CG offset
In the event of a single FMU failure, the XFER valve will be set to the closed position. Why should it stay set to closed?
to maintain fuel estimation integrity
Are you able to aerial refuel with a failed FMU?
YES
