Fuel System

Question 1

how much fuel does each tank hold?

Answer 1

using SGR of .8029 kg/ltr

Left and Right = 18267 kg

Center = 36349 kg

total around = 72882kg

Question 2

Explain the fuel pumps?

Answer 2

• Left and Right tanks have two AC motor driven pumps.
• center also has two AC motor pumps but they work at a higher rate than the left and right tank pumps
• when N2 drops below 50% then the center tank pumps are load shed
• fuel scavange system works when main tanks are below half and center tank is close to empty
• Several seconds after CTR L FUEL PUMP or CTR R FUEL PUMP the power is automatically removed from the center pump so that it isnt left running in a dry tank.
• The left main tank has a DC powered pump that supplies the APU when there is no AC power (prior to APU start and no ground power)

Question 3

What do the Fuel X Feed switches do?

Answer 3

They allow the pumps on one side to supply fuel to the other side. So one pump could supply fuel to either engine.

Question 4

What is suction feed?

Answer 4

When main tank pump pressure is low the engine can draw fuel from its corrisponding tank bypassing the pump.

Question 5

When does the Fuel configuration light come on?

Answer 5

• When left and right tanks differ by more than 900Kg +/- 200kg
• Center tank has more than 500Kg of fuel with the pumps not on
• Total usable fuel is less than 1000Kg in either main tank

Question 6

Explain the fuel jettison system

Answer 6

• Only center tank fuel
• 1200kg/min
• two dedicated duel pump units
• Load shedding of center fuel pumps removed
• FMC fuel calc figures are discontinued during jettison and calcs are restarted using the totalizer figure after jettison is complete.