Fuel Flashcards
Where is the Nitrogen Generation System Operability indicator?
The NGS Operability Indicator is located in the main wheel well adjacent to the APU Fire Control Panel.
What do IMBAL, CONFIG, and LOW (amber) lights indicate?
The IMBAL (amber) Alert is displayed when Main Tank fuel quantities differ by greater than 1000 lbs for greater than 60 seconds.
The Fuel CONFIG (amber) Alert is displayed when:
- Center Tank fuel quantity is greater than 1600 lbs, and
- both CTR FUEL PUMP switches are positioned OFF, and
- either engine is running
The Fuel LOW (amber) Alert is displayed when the respective Main Tank fuel quantity is less than 2000 lbs for greater than 30 seconds.
With all pumps operating, which fuel tank is burned first? Why?
Fuel pump output pressure differential ensures that Center Tank fuel is used before Main Tank fuel, even though all fuel pumps are operating.
Ctr Tank Fuel Pump pressure is higher than Main tank pumps.
When do the Center Tank Fuel Pumps automatically shut off?
Approximately 15 seconds after a continuous LOW PRESSURE signal has
been detected, the respective pump automatically shuts off.
What causes the Center Tank Fuel Scavenge Jet Pump to activate?
With the No. 1 Main Tank Fuel Pump FWD switch ON, the Center Tank Fuel Scavenge Jet Pump operates automatically to transfer any remaining Center Tank fuel to Main Tank No. 1.
Fuel transfer is initiated when a float valve in Main Tank No. 1 opens on fuel quantity in the No. 1 tank decreasing to 4500 lbs or less
With the loss of AC power, how is fuel provided to the engines?
When Main Tank fuel pump pressure is low, each engine can draw fuel from its corresponding Main Tank through a suction feed line that bypasses the pumps.
What is the purpose of the Crossfeed Valve?
When open, the Fuel Crossfeed Valve
interconnects the engine fuel manifolds to enable crossfeeding.
What is indicated by a bright blue Crossfeed VALVE OPEN light?
- bright blue when valve is in transit or valve position disagrees with selector
position - dim blue when the valve is open and the selector is positioned open
The light is extinguished when the Crossfeed Valve is closed with the CROSSFEED selector in the closed position.
What does the Engine Start Lever control? What occurs in each position?
When the Engine Start Lever is positioned to IDLE:
- the Ignition System is energized via the EEC
- the Spar Fuel Shutoff Valve is electrically opened (wing leading edge outboard of
the pylon)
- the Engine Fuel Shutoff Valve in the Hydromechanical Unit (HMU) opens via the
EEC
When the Engine Start Lever is positioned to CUTOFF:
- the Spar Fuel Shutoff Valve and Engine Fuel Shutoff Valve close, and
- the Ignition System de-energizes
What do the ENG VALVE CLOSED (blue) and SPAR VALVE CLOSED (blue) lights indicate?
The ENG VALVE CLOSED (blue) light illuminates:
- bright blue when valve is in transit or valve position disagrees with Engine Start Lever or Engine Fire Switch position
- dim blue when the valve is closed
The light is extinguished when the respective Engine (High Pressure) Fuel Shutoff Valve is open.
The SPAR VALVE CLOSED (blue) light illuminates:
- bright blue when valve is in transit or valve position disagrees with Engine Start Lever or Engine Fire Switch position
- dim blue when the valve is closed
The light is extinguished when the respective Engine Spar Fuel Shutoff Valve is open.
Which tank can the APU suction feed from?
If the AC fuel pumps are not operating, fuel is suction fed from Main Tank No. 1.
How is fueling and defueling accomplished?
at the single-point pressure fueling station in the
right wing.
What is the CAUTION regarding the crossfeed valve open with no fuel in the center tank?
CAUTION! A progressive fuel imbalance may occur during continued operation with the Crossfeed Valve open, no Center Tank fuel feed, and Main Tank Fuel Pumps operating within the normal pump output pressure tolerances. If a Main Tank Fuel Pump has a slightly higher output pressure than the other operating Main Tank Fuel Pumps, the dominant pump will provide fuel feed not only to its respective engine but also the opposite engine. This produces a higher flow rate out of the Main Tank with the dominant pump
and a reduction in flow rate out of the opposite Main Tank, resulting in a lateral fuel imbalance.
