7ER Fuel Flashcards
(25 cards)
From which tanks can fuel be dumped?
The center tank only (and only on the 767)
What is the meaning of a FUEL CONFIG light?
An imbalance (~1800lbs for 757, ~2000lbs +/-500 for 767) between the main tanks
-OR-
Low fuel ( <2200lbs) in either main tank (EICAS caution LOW FUEL)
-OR-
Fuel in center tank (>1200lbs) with both center pumps selected off
All cases also trigger an EICAS advisory FUEL CONFIG
What is the meaning of a FAULT light on the Fuel Jettison panel?
A transfer valve disagrees with the jettison switch position
With fuel in all tanks, and all pump switches on, which pumps have priority?
The center tank pumps override the main tank pumps so that the center tank fuel is used first
What is the fuel jettison rate?
About 1300lbs per minute
What is the meaning of a main fuel pump PRESS light?
Fuel output pressure from the pump is low
What is the meaning of a center fuel pump PRESS light?
Output pressure from the pump is low with the pump selected on
-OR-
The associated engine is below 50% N2 with a pump switch on, due to load shedding
Is the fuel jettison system inhibited on the ground?
No
Where are the fuel quantity and temperature indications?
On the Center Overhead
Which fuel tank is the temperature measured from?
The right main tank (757)
The left main tank (767)
The indication is always on the left
What does a proper fuel test look like?
Quantities: all 8s
Total Quantity: 1, followed by all 8s
Temperature: 186
What is the function of the Fuel Jettison selector?
OFF - closes both jettison transfer valves
ON - opens both jettison transfer valves
What is the function of the Fuel Jettison NOZZLE switches?
ON - opens the respective jettison nozzle
Off (blank indication) - closes the respective jettison nozzle
What powers the fuel pumps?
AC power
What is the meaning of an EICAS caution FUEL SYS PRESS?
All fuel pumps have low pressure
-OR-
All fuel pumps on one side have low pressure with the crossfeed switch(es) off
What happens if the EICAS advisory CTR FUEL PUMP displays?
The pump will automatically turn off after a few seconds, and about 1000lbs of fuel will remain in the center tank, which will be moved to the wing tanks by a scavenge system
What are the approximate fuel tank capacities?
757: 14,500lbs per wing, 47,000lbs in the center
763: 40,000 lbs per wing, 80,000lbs in the center
Why can there sometimes be a difference between the sum of the tank fuels and the totalizer fuel?
The totalizer fuel comes from a separate calculation of the Fuel Quantity Processor Unit
How is Calculated fuel calculated?
The FMC subtracts fuel used, as measured by the fuel flow gauges, from the fuel quantity at engine start. It does not account for APU fuel burn
How many fuel pumps are required to properly feed an engine
One
Which tanks can suction feed an engine?
Wing tanks only
What is a hazard of suction feeding?
Dissolved air can restrict fuel flow at higher altitudes and cause a power loss or flameout
What is the approximate total fuel capacity of the 752?
75,000lbs or 76,700lbs
What is the approximate total fuel capacity of the 753?
76,700lbs
