Fuel Flashcards
How is fueling accomplished?
Aircraft fueled at single-point pressure fueling station located on the right wing.
*The fueling station panel is energized when the panel door is open.
*The refueling system is
powered by the hot
battery bus; however,
one of the following
electrical sources must
be available:
*External power
connected, regardless if
external power has been
selected
*APU generator power
*Battery power (BAT
switch must be ON)
What does an IMBAL alert on the Fuel Quantity Indicator indicate?
IMBAL: Main tank fuel quantities differ by 1000 pounds for greater than 60 seconds
Alert remains until the difference between main tanks is 200 lbs or less
What does the LOW alert on the Fuel Quantity Indicator indicate?
LOW: Respective Main Tank fuel quantity is less than 2000 pounds for greater than 30 seconds.
What does a CONFIG alert on the Fuel Quantity Indicator indicate?
Misconfiguration of the fuel system boost pumps
CONFIG: Center tank fuel quantity is greater than 1600 pounds, both Center Fuel Tank switches are OFF, either engine is running.
What does INSUFFICIENT FUEL on the Fuel Quantity Indicator indicate?
The FMC predicted fuel at the destination is less than 2000 pounds
With all fuel pumps operating, what ensures center tank fuel is used before main tank fuel?
Higher fuel pump output pressure from the center tank pumps ensures center tank fuel is used first
When do the Center tank fuel pumps shut off automatically?
Approximately 15 seconds after a continuous LOW-PRESSURE signal has been detected.
Turning the pumps off will reset the logic if they’re turned on again and will run until the shutoff logic is met again
How is fuel provided to the engines without the fuel pumps?
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.
Center tank does not suction feed
When does the center tank fuel scavenge jet pump activate?
Fuel quantity less than 4500 pounds in Main Tank 1. Continues for the remainder of the flight.
With main tank No. 1 FWD FUEL PUMPS switch ON, center tank scavenge jet pump operates automatically to transfer any residual center tank fuel to main tank # 1.
When main tank No. 1 fuel quantity decreases to 4500 lbs or <, a float valve to the scavenge jet pump opens and uses motive flow from the main tank No. 1 forward pump to transfer residual fuel from the center tank.
Once the scavenge process begins, it continues for the remainder of the flight, transferring 220–450 lbs per hour.
What is the purpose of the Cross-feed Valve?
- To provide cross-fed fuel to the operative engine during single engine operations, thereby maintaining fuel balance.
- To balance fuel during normal operations.
DC powered
What does the engine start lever control?
Fuel flow to the engine is controlled by the fuel SOV located in each engine and wing spar
The position of the fuel SOV is controlled by the start levers below the throttles
What does a bright blue illumination of the VAVLE OPEN on the Fuel Panel indicate?
Valve is in transit or valve position disagrees with its commanded position.
*dim blue VALVE OPEN light indicates valve is open with the selector positioned open)
*CROSS FEED selector closed with the valve close then the light is extinguished
What does the dim illumination of an ENG VALVE CLOSED light indicate?
The ENG VALVE is closed.
*When the valve is open and the start levers are in IDLE then light is extinguished
What does a bright illumination of a SPAR VALVE CLOSED light indicate?
A bright ENG VALVE CLOSED light indicates the valve is in transit or disagrees with the start lever or FIRE SWITCH position
Where could the APU suction feed fuel from?
If fuel pumps are not on, fuel is suction fed from Left main tank.
Where is the Nitrogen Generation Operability Indicator located?
Right Main Wheel Well.
