FUEL

Question 1

The wing feed tanks are designed to maintain approx ___min supply of fuel for each engine.

Answer 1

30 mins

Question 2

What compensates for the tank pressure increasing/decreasing due to altitude changes?

Answer 2

climb/dive valves

Question 3

What characteristics make the fuel tank crash-worthy?

Answer 3

• 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

Question 4

The fuel supply system is a ______, ______, ______-type system.

Answer 4

crash-worthy, fully automatic, suction-type system

Question 5

8 Major functions of the FMUs:

Answer 5

• 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

Question 6

What is the fuel burn sequence?

Answer 6

1. aft sponson tank
2. mid and forward MAT (if installed)
3. wing auxiliary tanks
4. forward sponson tanks

Question 7

What tanks have suction lift pumps?

Answer 7

feed tanks

Question 8

What tanks have boost pumps?

Answer 8

• sponson tanks
• wing aux tanks
• MATs (if installed)

Question 9

When do the boost pumps come on when TRUMP BOOST - ON or AUTO is selected?
(4ish instances)

Answer 9

• 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

Question 10

When does FEED TANK LOW come on and when does it turn off.

Answer 10

• 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

Question 11

The XFER valve is unavailable (slashed) during the following fuel system operations:

Answer 11

• 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

Question 12

T/F: The FMU follows the same burn sequence for single engine operation as it would for both engines running.

Answer 12

TRUE

Question 13

During single engine operation, commanding TRUMP BOOST ______ and selecting XFER valve to ______ will do what and why?

Answer 13

ON ; OPEN
mitigate uneven fuel burn to minimize any lateral CG offset

Question 14

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?

Answer 14

to maintain fuel estimation integrity

Question 15

Are you able to aerial refuel with a failed FMU?

Answer 15

YES

Question 16

What enables you to be able to aerial refuel with a failed FMU and how?

Answer 16

the EARP (Emergency Aerial Refueling Panel) is used to manually open/close the refuel valves for the affected wing aux tank, forward sponson, and the affected sponson bypass valve.

(if anyone has a better way to word this question please do)

Question 17

Fuel is dumped to reduce aircraft gross weight at a rate of approximately ______ppm.

Answer 17

800 ppm