Fuel Flashcards
Center Tank Press lights
- Pump ON with associated N2 or N3(RR) below 50%
- inhibited with C tank switch Off
FUEL CONFIG light
- Center pumps off w/ 1200 lbs+ fuel in Center tank
- Fuel Imbalance of 1800 lbs+ between Main tanks
- Fuel below 2,2000 lbs in either Main tank
Where is Fuel Temp measured?
Right main tank (757)
Left main tank (767)
Normal Fuel Supply
- L Fuel Manifold (L AC FWD, L AC AFT, C Left OVRD) —> left engine
- R Fuel Manifold (R AC FWD, R AC AFT, C Right OVRD) —> right engine
- L AC FWD —> APU
Where is totalizer fuel displayed
- total fuel quantity indicator
- FMC PERF INIT and PROG 2
FUEL PUMPS and Output pressure
Left Tank:
- 2 x AC fuel pumps (FWD and AFT) - single pump can supply 1 engine under all conditions
- 1 x DC fuel pump - back up for APU start
Right Tank:
- 2 x AC fuel pumps (FWD and AFT) - single pump can supply 1 engine under all conditions
Center Tank
- 2 x AC Fuel Override pumps - supply greater output pressure and have priority over main tanks so that center tanks is used first
Fuel scavenge pumps
- operated automatically
- transfers remaining fuel in center tank to the left tank (757) / both tanks (767)
- begins when left tank is approx 1/2 full
DC Fuel Pump logic
- No AC power supplied to aircraft
- BATT switch ON
- APU start
How many crossfeed valves
Single or Dual (as installed)
- only one is needed for successful crossfeed
Suction Feed
- possible from main tanks only
- when fuel tank pump pressure is low
Fuel tank quantity (757)
Center - 46,200 lbs
Left Main - 14,600 lbs
Right Main - 14,600 lbs
Total 75,400 lbs
Fuel tank Quantity (767)
Left Main tank - 40,600 lbs
Right Main tank - 40,600 lbs
Center tank - 80,400 lbs
Total - 161,600 lbs
Fuel Jettison ON (767)
- two dual jettison/OVRD pumps operate (4 jettison pumps total)
- Fuel jettison valves open
- jettison rate of approx 2600 lbs per min
- jettison via nozzles inboard of each outboard aileron
How is center tank residual fuel transferred
- Center tank residual fuel is automatically transferred to both main tanks (767) or left main tank (757) by jet pumps
- Jet pumps begin to operate when the main tanks (767) or left main tank (757) are approximately half empty