757 Systems - Fuel

Question 1

What tank does the APU get fuel from?

Answer 1

Left main tank

Question 2

What is the purpose of the DC pump?

Answer 2

Provides the APU fuel when AC power is not available

Question 3

Do all AC pumps have the same output pressure? Why?

Answer 3

No, the 2 Center tank pumps have higher pressure than the 4 main tank AC pumps so that the center tank fuel is used before either main tank fuel.

Question 4

How many crossfeed valves are there?

Answer 4

1 or 2 depending on configuration

Question 5

When are the Center Fuel Pump PRESS lights inhibited?

Answer 5

When the respective Center Pump Switch is OFF.

Question 6

When AC power is established and the APU is running, what pump automatically supplies fuel to the APU, regardless of switch position?

Answer 6

Left forward fuel pump

Question 7

When will the Center Fuel Pumps not operate, even though their switches are ON?

Answer 7

1. When the respective engine is OFF
   or
2. There is no usable fuel in the center tank

Question 8

How is CALCULATED fuel derived?

Answer 8

TOTALIZER fuel at engine start minus fuel burned

Question 9

When will the FUEL CONFIG light illuminate?

Answer 9

1. Left and Right main tanks differ by 1800 lbs
2. Center Pump switches OFF and > 1200 lbs in center tank
3. Either Main Tank < 2200 lbs of fuel (EICAS also shows LOW FUEL)