Each wing tank contains the following pumps?
- Ejector fuel pump
- Wing AC electric fuel pump
- 3 scavenge ejector pumps
- DC electric fuel pump (right tank only)
What is the purpose of the DC electric fuel pump?
Provides pressurized fuel for normal APU operation and engine start when AC power or AC fuel pump is not available
Where is the fuel low level sensor located?
One in each tank located in the collector box
Is the fuel low level sensor independent of the fuel quantity indicating system?
Yes
Fuel density
6.76 lb/us gal
Total fuel quantity?
20,935 lbs
When will the fuel low level warning come on?
660 lbs
Where is fuel temperature measured?
Left fuel tank
What is the purpose of the scavenge pumps?
Maintain the fuel level in the collector tank
How many scavenge pumps per wing tank?
3
When will the FUEL IMBALANCE EICAS CAUTION message appear?
800 lbs fuel imbalance
What is the only way to close the fuel shutoff valves?
Actuation of the fire handles
When will the FUEL IMBALANCE cation message disappear?
When the fuel imbalance is reduced to 800 lbs
How does the fuel crossfeed work?
- Crossfeed valve supplies fuel to both engines from one tank
- Amount of fuel supplied to the lower level side is higher than the actual fuel burn on that engine
What is the purpose of the collector tanks?
- Keep fuel pumps submerged
* Ensures constant fuel flow to the engine
What is the purpose of the surge tank?
Collects fuel that enters the vent system during wing down and uncoordinated maneuvers
What is the purpose of the AC wing fuel pumps?
- Engine starts
- Crossfeed operations
- Backup pump if ejector pump fails
