Fuel System

Question 1

How many fuel pumps does each fuel tank use?

Answer 1

Two AC powered fuel pumps

Question 2

What ensures that center tank fuel is used before main tank fuel, even though all pumps are operated?

Answer 2

the center tank pumps produce higher pressure

Question 3

If main tank fuel pump pressure is low, how can the engine draw fuel from the main tank?

Answer 3

there is a suction feed line, however, at high altitude, air may collect in this line and restrict fuel flow

Question 4

The fuel crossfeed valve interconnects the engine fuel manifolds. how is the valve operated?

Answer 4

DC motor operated from battery bus

Question 5

There are two fuel shutoff valves per engine. Where are they?

Answer 5

Spar fuel SOV valves located at engine mounting wing stations (DC motor operated from hot battery bus)
Engine fuel SOV. powered by battery bus.

These close whenever the respective fire switch is pulled or start lever in CUTOFF

Question 6

What does the center tank fuel scavenge jet pump do?

Answer 6

With main tank fuel pump 1 FWD on, the center tank fuel scavenge jet pump operates automatically to transfer remaining center tank fuel to main tank 1. begins when main tank No. 1 is about one half full

Question 7

Where is the fuel temperature sensor?

Answer 7

Main tank No. 1 using AC power

Question 8

How many pounds does each main tank hold?

Answer 8

8,630 lbs

Question 9

how many pounds does the center tank hold?

Answer 9

28.803

Question 10

how many pounds of fuel total can the a/c hold?

Answer 10

46,063

Question 11

ENG VALVE CLOSED and SPAR VALVE CLOSED lights

Answer 11

extinguished- related engine or spar fuel SOV open

bright blue- related engine or spar fuel SOV valve in transit, or valve position and engine start lever or engine fire switch disagree

dim blue- related engine or spar fuel shutoff valve closed

Question 12

fuel crossfeed VALVE OPEN light

Answer 12

extinguished- crossfeed valve is closed

bright blue- crossfeed valve in transit or valve position and crossfeed selector disagree

dim blue- crossfeed valve open

Question 13

Center Tank FUEL PUMP LOW PRESSURE light (amber)

Answer 13

fuel pump output pressure is low and fuel pump switch is ON.

If extinguished, the fuel pump output pressure is normal or fuel pump switch is OFF

Question 14

Main tank FUEL PUMP LOW PRESSURE lights

Answer 14

when amber, the fuel pump output pressure is low ore the fuel pump switch is OFF

Question 15

fuel LOW alert (amber) on upper DU

Answer 15

1. fuel qty less than 2000 lbs in related main tank, which remains until fuel qty is increased to 2500 lbs

Question 16

fuel CONGIF alter (amber) on DU

Answer 16

will display amber when:

1. either engine running
2. center tank qty greater than 1600 lbs AND
3. both center fuel tank pump switches positioned OFF

Question 17

fuel IMBAL alert (amber) on DU

Answer 17

1. main tanks differ by more than 1000 lbs

Question 18

What are the fuel measuring sticks in the wings for and how many?

Answer 18

Allows comparison of fuel quantity or weight as determined from measuring stick reading and fuel weight indicated by fuel quantity indicators.

6 installed in each main tank and four in the center