FUEL SYSTEM

Question 1

How many primary fuel tanks are there?
How many total fuel tanks?

Answer 1

3 primary fuel tanks
7 total including collector tanks and surge tanks

Question 2

Total fuel quantity

Answer 2

38,350lbs

Question 3

Wing tanks fuel quantity

Answer 3

6725lbs

Question 4

Center tank quantity

Answer 4

24,900lbs

Question 5

What is the primary way to move fuel?

Answer 5

Motive flow. Pressure from the Engine Driven Pump (EDP) passes through a Venturi-shaped fuel ejector. A low pressure is created. The suction caused by low pressure moves the fuel out of the tank.

Question 6

What is the AC Boost Pumps used for?

Answer 6

An AC boost pump in each collector tank is the backup for the main fuel ejector pump.
Engine fuel feed backup
APU fuel feed backup
Fuel crossfeed
Fuel transfer
Supports engine start in flight

Question 7

What is the fuel inverting system?

Answer 7

Uses Nitrogen-Enriched AIR to reduce the risk of fuel fumes igniting in fuel tanks

Question 8

What is the Scavenger System?

Answer 8

A scavenger ejector pump in each wing tank continuously moves fuel from the wing tank to the collector tank. Requires motive flow from the EDP to operate.

Question 9

Center tank to wing tank transfer

Answer 9

Fuel from the center tank is automatically transferred to the wing tanks by transfer ejector pumps. When 85.6% of maximum wing tank usable
fuel is left, a float valve opens to let the center tank transfer ejector pumps to fuel.
Crew have no control over this transfer process.

Question 11

How much fuel can you transfer from wing tanks to center tank?

Answer 11

1000lbs

Question 11

How much fuel can you transfer from wing tanks to wing tank?

Answer 11

FQC only permits 500lbs

Question 12

MAN XFR switch

Answer 12

Allows fuel transfer from wing tanks to wing tank or wing tank to center tank.

Question 13

Gravity transfer system

Answer 13

A gravity transfer manifold connects the left and right wing tanks. Separated by gravity crossflow valve. The GRAV XFR switch opens the valve so that the wing tanks can equalize.
If the crossflow switch is inoperative, the gravity crossflow valve can be overridden on the ground only.

Question 14

Automatic fuel balancing

Answer 14

Imbalance of 400lbs between wing tanks. The heavier tank AC boost pump turns on automatically. Both engines are fed directly from the heavier tank until within 100lbs of each other.
Only activated when center tank is empty.
If pressure drops in the fuel feed line, both AC boost pumps activate and automatic fuel balancing is no longer available.