Fuel Flashcards
How many fuel tanks do we have and what are their approximate capacities?
- 7 fuel tanks (+ horizontal stab for pax airplanes)
- 1 and 4 mains = 13.2 kgs each
- 2 and 3 mains = 38.1 kgs each
- center tank = 52.1 kgs.
- 2 and 3Reserves = 4.0.kgs. each
- total capacity = 163, 042
Note:FCOM, VOL 2; 12.20.4
What commands fuel valves to open or close and fuel pumps to turn on and off according to fuel management logic?
• Fuel system management cards (FSMCs)
Note:FCOM, VOL 2; 12.20.11
Which crossfeed valves are affected by flap extension on the ground?
• 2 and 3. They are closed by the FSMCs when flaps extend to takeoff position on the ground.
Note:FCOM, VOL 2; 12.20.12
Which fuel pumps are system logic pumps, in other words, commanded to turn on and off by system logic during normal operations?
• Override/jettison pumps 2 and 3. They are inhibited from operating when pressure is detected from both CWT override/jettison pumps.
Note:FCOM, VOL 2; 12.20.12
Trace the flow of fuel to the engines when there are 7700 kgs or MORE fuel in the Center Wing Tank., from blockout.
- Both CWT pump switches should be ON.
- X-feed valves 2 and 3 close when flaps extended for takeoff
- CWT pumps feed engines 1 and 4.
- Main pumps 2 and 3 feed their related engine.
After Takeoff with Flaps not in 10 or 20
All x-feed valves are open
CWT pumps feed all engines
Note:FCOM, VOL 2; 12.20.12
Trace the flow of fuel to the engines when there is LESS than 7700 kgs of fuel in the center wing tank, from blockout.
- Both CWT tank pumps should be off.
- X-feed valves 2 and 3 close when flaps extended for takeoff.
- Override/jettison pumps 2 feed engine 1
- Override/jettison pumps 3 feed engine 4.
- Main pumps 2 and 3 feed their related engine.
After Takeoff with Flaps not in 10 or 20
All x-feed valves are open
• Override/jettison pumps 2 feed engine 1 and 2
• Override/jettison pumps 3 feed engine 3 and 4
Note:FCOM, VOL 2; 12.20.12
When do the FSMCs open the reserve transfer valves?
- When main tank 2 or 3 fuel quantity decreases to approximately 18,200 kgs.
- Fuel transfers from reserve tanks 2 and 3 to the related main tank.
Note:FCOM, VOL 2; 12.20.11
Under what conditions would fuel automatically transfer from main tanks 1 and 4 to their adjacent tanks 2 and 3?
• During fuel jettison, when either main tank 2 or 3 fuel quantity decreases to 9,072 kgs.
Note:FCOM, VOL 2; 12.20.11
Can fuel be manually transferred from any tank to another tank?
- Yes, there is a Main Tank 1 and 4 Transfer Switch on the overhead panel.
- Fuel can transfer from the outboard to the inboard main tanks, to approximately 3,200 kgs remaining in each outboard main tank.
Note:FCOM, VOL 2; 12.20.11
State what occurs when you select the Fuel Jettison Switch to A or B.
- Arms the jettison system
- Displays preselected fuel to remain on EICAS
Note:FCOM, VOL 2; 10.4
Describe how the fuel quantity indication changes upon termination of fuel Jettison
- The fuel to remain quantity indication changes from magenta to white.
- The fuel to remain quantity flashes for 5 seconds.
Note:FCOM, VOL 2; 12.20.15
What occurs when you push either fuel jettison nozzle valve to ON during the QRH fuel jettison procedure?
- It activates all override/jettison pumps in the tanks containing fuel (pump switches must be on).
- The required jettison nozzle valve also opens.
Note:FCOM, VOL 2; 12.20.14
What is the source of fuel for the APU?
• Normally supplied from main tank 2.
• When ac power is available, fuel is supplied by main pump 2 aft.
• If AC power is not available, a dedicated DC pump in main tank 2
supplies fuel to the APU.
• Main pump 3 aft operates to prevent tank to tank transfer and provides
fuel if main pump 2 aft fails (with aircraft exceptions)
Note:FCOM, VOL 2; 12.20.11
In general, how would you handle a fuel imbalance situation?
• By opening or closing crossfeed valves and turning off and on fuel pump switches (refer to QRH and Supplementary Procedures)
Note:FCOM, VOL 2; 12.20.3
What is the impact on the aircraft of excessive fuel imbalance?
- Adversely affects CG
- Aerodynamic drag
- Fuel economy
Note:FCOM, VOL 2; 12.20.3
When is an engine on suction feed, and how would you correct a suction feed situation?
- An engine is on suction feed when main tank fuel pressure is low.
- Open the appropriate fuel crossfeed valve from a main tank with operating pumps.
Note:FCOM, VOL 2; 12.20.3