Fuel Flashcards
Will you get a center pressure low lights if the center pumps are turned off?
No they are inhibited.
How many fuel pumps are in each fuel tank?
2
Are the fuel pumps ac or dc?
Ac
Where does the apu get fuel from?
Left fuel feed system
What pump provides fuel for apu when ac power is not available?
Dc fuel pump in the left main tank
Where do fuel from the surge tanks drain into?
Center tank
Where are surge tanks located?
Each wing tip
When do you get a fuel config light?
- A fuel unbalance of 2000 LBS ± 500 between main tanks (EICAS Advi-sory message - FUEL CONFIG).
- Low fuel quantity less than 2200 LBS in either main fuel tank (EICAS Caution message - LOW FUEL).
- Center fuel pump switches are off with greater than 1200 lbs in the cen-ter tank (EICAS Advisory message - FUEL CONFIG)
Name approximate fuel quantities?
Main tanks each - 40000
Center tank - 80000
Total 160000
When does the associated fuel pressure light come on?
When the fuel pump pressure is low.
What does the L or R FUEL SYS PRESS message mean?
EICAS caution messages, L or R FUEL SYS PRESS, indicate low fuel pressure in the left or right fuel manifold.
Are the center tank pumps more powerful than the main tank pumps?
Yes
Why does the aircraft drain the center tanks first?
Because the center fuel pumps are more powerful than the main tank pumps.
When is the center tank pumps inhibited?
To reduce electrical loads, the center tank pumps are inhibited in flight or on the ground when the associated N2 is less than 50% RPM. Thus both center tank pumps are inhibited with the engines shutdown.
What happens to the center tank pump inhibit when the fueling door is opened?
The inhibit is cancelled
Where does the scavenge ejectors transfer fuel to?
From center tanks to each main tank
Other than on apu start, when does the dc fuel pump run?
In addition, the pump operates automatically in-flight to provide fuel to the left engine when left engine N2 RPM drops below a preset value, the APU Switch is OFF, and left engine fuel manifold pressure is low. When N2 RPM increases above a preset value, the DC pump shuts down.
Can the engines suction feed fuel?
When main tank fuel pump pressure is low, each engine can draw fuel from its corresponding main tank through a suction feed line that bypasses the pump
After apu is turned on and running, which fuel pump takes over?
The left fwd fuel pump takes over regardless of switch position
Can the left fwd fuel pump be turned off on the ground while the apu is running?
No
Can the left fwd fuel pump be turned off in the air while the apu is running?
Yes
What happens to the apu if you turn off the left fwd fuel pump in flight?
The apu keeps running as any operating ac fuel pump in the left system can supply fuel to it. If you turn the left fwd pump off, the left aft is still working so the apu keeps running.
How does the fueling station normally get power?
Thru the ground handling bus.
How does the fueling station get power if the ground handling bus is not available?
Thru the switch for the hot battery bus.
How does the tank overfill system work?
If the surge tanks sense any fuel in it, the system shuts off all the fueling valves.
