Fuel Flashcards
Describe how fuel gets from the gas truck to the engine
1) Fuel pumped into airplane through over wing filling ports or single point refueling
2) The main or center tanks are filled as selected on the refueling panel
3) Fuel travels from main tanks by gravity or scavenger ejectors (once the engine is running) to the collector tanks
4) From the collector tanks either the boost pumps or the main ejectors send fuel from the collector tanks towards the engine for combustion
Describe the fuel tank venting system
There are NACA vents and climb vents. The tanks are positively pressurized
Describe the fuel quantity gauging system
A DC type capacitance system indicates usable fuel
Is the capacitance system calibrated for ground or flight conditions?
Both. In flight the computer compensates for pitch and roll
Aside from the digital readouts, is there any other way to determine fuel quantity?
Yes. There are 5 magnetic level indicators that can manually be checked on the exterior of the aircraft, 2 under each wing and 1 under the fuselage
Can raw data from the MLIs be used to determine the fuel level
No. A conversion chart must be used found in the AFM
Is dispatch authorized with the fuel quantity gauging computer inoperative?
No
Where is the bulk fuel temperature sensor?
Right wing tank
Explain the automatic fuel crossflow system
The FQGC initiates a crossflow by activating the bi-directional crossflow pump when it detects a fuel imbalance of 200 pounds between the wings. The crossflow pump will continue to operate until the low wing has 50 pounds more fuel than the wing with the previous higher quantity.
How is fuel manually transferred?
First, press the MAN XFLOW AUTO OVERIDE switch light. Then press the L or R XFLOW switch light on the low side (remember “press the light on the light side”) to activate the bi-directional crossflow pump. The GRAVITY XFLOW switch light could also be pressed allowing fuel to freely move from one tank to the other. By banking the aircraft or entering a gentle slip, gravity will move the fuel.
Where does the APU get fuel from?
A dedicated boost pump in the left collector tank
If the APU boost pump fails, will the APU keep running?
Yes, however it will not start unless the pump is operating
Will the main engines start without their respective boost pump running?
Yes
After turning on the boost pumps, what do the switch lights look like?
The upper section of the switch lights illuminate “on”, because low pressure is detected in the fuel lines and the pumps begin running
After starting both engines, what do the fuel switch lights look like?
The light extinguishes because the pumps enter the standby mode. Motive flow supplies the fuel to the engines.
