Fuel System

Question 1

General

Answer 1

Crash worthy, suction-type system with a self-sealing main tank. The system is capable of pressure refueling, gravity refueling, and HIFR. It can prime, dump, indicated quantity, and warn of low fuel levels.

Question 2

Lines

Answer 2

Include self-sealing breakaway valves that stop fuel flow in the event of damage.

Question 3

Particle of Fuel

Answer 3

• Start in the tanks
• Fuel lines
• engine driven fuel pump
• fuel filter
• HMU

Question 4

Main Tank

Answer 4

• Two interconnected cells, interconnect level is 270-600 pounds
• system capacity is 590 usable gallons
• Left Cell: 2 high level shutoff floats, check valve, sump drain, and vent; this cell is the refueling cell
• Right Cell: 2 check valves, sump drain, a vent, APU fuel line, and dump system

Question 5

External Tanks

Answer 5

Inboard pylons accept a crash-worthy, ballistically hardened 120 or 113 gallon capacity external tank

• tank has a self-sealing breakaway valve
• jettisonable and refuelable through main system

Question 6

Aux Tank Jettison

Answer 6

ALL STORE JETT inhibited with less than 40 gallons (272 pounds); requiring SEL JETT to be used.

Fuel gauge only indicates in 50 pound increments so SELL JETT should be used when there is less than 300 pounds.

Question 7

PUMP/VALVE FAIL

Answer 7

single valve of pump fails

Question 8

AUTO FUEL XFER FAULT

Answer 8

“indicates a lack of fuel transfer aux tanks to main tank” due to failed closed transfer valve, both transfer/dump pumps inop, FMCP control fail, or blockage

Question 9

Right Cell Caution

Answer 9

If right cell fills faster than left cell, monitor gauges closely. If difference in cell quantities persists, stop transferring fuel before right cell is full (approx. 1700 pounds)

Why? a clogged vent in left cell won’t activate the shutoff floats and you could get the pressure in the cells to exceed 2 and rupture the fuel system

Question 10

When can you initiate unmonitored fuel transfer?

Answer 10

main tank below 3200 pounds

Question 11

Manual fuel transfer check

Answer 11

When main fuel tank capacity (4012 pounds of JP5) has decreased approximately 300 pounds.

Question 12

Automatic fuel transfer initiated?

Answer 12

At AUTO, the fuel management logic is not initiated until the main fuel tank level depletes to approx. 2640 pounds.

Question 13

Primary Fuel

Answer 13

Fuel authorized for continuous unrestricted operations

Question 14

Restricted Fuel

Answer 14

Fuel that imposes operational restrictions on the aircraft

Question 15

Emergency Fuel

Answer 15

Fuel that is to be used for minimum time when primary or restricted fuels are unavailable in cases of emergency or operational necessity

Question 16

Primary Fuels

Answer 16

JP5 (F-44)
JP8 (F-34)
A++ (F-24)
TS-1

Question 17

Restricted Fuels

Answer 17

A1 (F-35)
A
JP4 (F-40)
B

Question 18

Emergency Fuels

Answer 18

JP8+100 (F-37)

F-27

Question 19

Operational Restrictions with JP4/JET B

Answer 19

1. All takeoffs shall stabilize in a hover with no fuel pressure cautions for a min of 10 seconds before commencing transition to forward flight.
2. Single engine training is prohibited.
3. Operating characteristics may change. Lower operating temps, slower acceleration, and shorter range may be experienced.
4. Due to the vapor qualities of mixed JP4/JET B, the next two refuelings with a primary fuel shall be treated as if JP4/JET B is in the tanks