767 Fuel
What occurs when the fueling door is opened?
- Powers the controls and indicators, and - Removes the center tank pump inhibit
What do the center tank pump PRESS light indicate?
- Pump output pressure is low, or - Associated engine N2 is below 50% with the pump selected ON
What do the main tank pump PRESS light indicate?
- Pump output pressure is low, or - Pump is selected off
If you wanted to crossed fuel from the left tank to the right engine, how would you do that?
- Select crossfeed ON - Select right side fuel pumps OFF
What is the difference between sensed fuel quantity and calculated fuel quantity on the FMC?
- Sensed quantity accounts for APU fuel burn - Calculated qaunity is the calculated engine burn subtracted from the original sensed quantity
What does selecting the jettison pump selector to ON do?
- Turns on the jettison pumps (associated with fault light) - Opens the transfer valve (associated with fault light) - inhibits UFI - Inhibits calculated fuel quantity on the FMC - L3 and R3 window heat is load shed
When does the FUEL TEMP EICAS message appear?
-37C
How many fuel pumps are needed for all thrust conditions?
1 in each tank
How many probes are in the right fuel tank?
1 quantity sensing probe
Which tanks are vented to the surge tanks?
All 3 tanks
What occurs if fuel enters the surge tank while refueling?
All fueling valves are closed to prevent fuel spillage.
How long does it take to jettison a full center tank?
Approximately 30 minutes
What must happen with the XFEED valve every flight?
It must be exercised once every flight since it a required for ETOPS
What is the purpose of the fuel quantity processor?
It takes information from the probes in each tank and corrects it for temperature and pressure
What does the EICAS message L or R XFER VALVE and FAULT light indicate?
Jettison XFER valve has failed, valves should be closed when switch is off and should be open when switch is on.
What does a blank fuel qauntity display indicate?
No power or a failure of the quantity sensing system
Is center tank fuel available with no AC power?
No, because there are no bypass valves.
What is the status of the center tank pumps if the right engine is running and the left engine is off?
Right center tank pump is ON if selected, left pump is off regardless of position
Why do the center tank fuel pumps have a higher output than the main tank pumps?
So that center tank fuel is consumed before main tank fuel
What does the EICAS advisory LOW FUEL and FUEL CONFIG light indicate?
Total useable fuel is below 2,200lbs in either tank
What does a FUEL DISAGREE CDU scratchpad message indicate?
Totalizer and calculated quantity differ by 3000lbs or more
How does fuel flow to the engines if AC pump output is low?
Via a suction feed line that bypasses the pumps.
How is fuel quantity data taken?
Via probes in each tank
767-300 Center tank capacity
80,400lbs (36,469kgs)
What is the correct procedure to jettison fuel?
Turn the pump selector to ON, then turn the nozzle switches ON
What occurs when fuel is below 1200 lbs in the center tank?
- CTR PUMP LOW PRESS Advisory message displays and - Both pumps are deenergized by Universal Fault Interruptor Circuitry (UFI). *You should turn off both center tank pumps when this happens
What does the fuel quantity processor send information to?
- FMC - FUEL CONFIG - Fuel quantity indicating system
What indicates a failed crossfeed valve?
- EICAS message FUEL CROSSFEED - FUEL CONFIG LIGHT - VALVE light illuminated in the fuel crossfeed button
How many AC powered pumps are in each tank?
2
What provides the force to jettison fuel through a manifold?
2 dual pump units in the center tank, they were at approximately 2600PPM
How many probes are in the center fuel tank?
2 quantity sensing probes
How many probes are in the left fuel tank?
2; 1 temperature probe and 1 quantity sensing probe
How much more powerful are the center tank pumps compared to the main tank pumps?
2x as powerful
Minimum in flight fuel temperature
3 degrees above the freezing point of the fuel being used.
How many fuel tanks are there?
3; left, right and center
767-300 Main tank capacity
40,669lbs (18,447kgs)
After the Center tank fuel pump low pressure lights illuminate, what transfers the low remaining fuel to the main tanks?
A scavenge pump
What does a check valve in each main tank serve to do?
A bypass valve to allow fuel to be sucked out of the tanks by the engine driven pumps when AC power isn't available:
Where is the aircraft fuel from?
A common point on the left wing
When should the main tank pump switches be turned on?
After engine start
What happens to FMC fuel after a jettison?
It is set equal to the totalizer
Why is the temperature probe in the left fuel tank?
Because it is the coldest fuel tank.
Why is fuel flow restricted at higher altitudes when the suction feed line is supplying the engines?
Because of dissolved air released from the fuel tank due to decreased air pressure.
How is the output of the DC pump separated from the left engine manifold?
By a check valve, restricting the output to the APU
How is refueling provided?
By a refueling valve, which uses either the tank pumps or fuel truck suction (not available for the center tank)
How is refueling provided?
By a refueling valve. The aircraft can be defueled using the AC pumps or fuel truck suction.
What occurs when the FUEL CROSSFEED switch is pushed out? (bar not in view)
Commands the crossfeed valve to close
What occurs when the FUEL CROSSFEED switch is pushed in? (bar in view)
Commands the crossfeed valve to open
What does the EICAS message FUEL JET NOZ and the VALVE light in the nozzle switches indicate?
Fuel jettison nozzle is not in the commanded position
What does the EICAS message L or R JET PUMP and FAULT light above the pump selector indicate?
Fuel jettison pump is inoperative
What does the EICAS advisory FUEL CONFIG and FUEL CONFIG light indicate?
If either main tank fuel quantity differs by more than 2,000 lbs. (plus or minus 500 lbs.) or the center fuel pump switches are OFF with more than 1.200 lbs. of fuel in the center tank
When and why are the center tank pumps inhibited?
Inhibited below 50% N2 to reduce electrical loads
What is the purpose of the Nitrogen Generation System (NGS)?
It converts bleed air to nitrogen enriched air during all phases of flight and is delivered to the center fuel tank to reduce the flammability of the tank.
What occurs to the associated center tank boost pump if the engine falls below 50% N2 in flight?
It is load shed
Where are the indicators for the NGS located?
Left main wheel well
Are there any controls or indications for the DC pump?
No
Does each fuel qauntity indication come from the same calculation?
No
How can total fuel quantity be viewed?
On the fuel panel or on the FMC
Where are the surge tanks located?
Outboard of both main tanks
What will the fuel tank pumps switches indicate when off?
PRESS
What does the CDU scratchpad message INSUFFICIENT FUEL indicate?
Predicted fuel at destination is less than the FMC reserves
What do check valves on each fuel pump serve to do?
Prevent reverse flow of fuel from the fuel manifold back into the tanks
When should the center tank pumps be turned on?
Prior to engine start (PRESS lights remain illuminated to indicate the pumps aren't yet operating)
How does fuel flow to the engines?
Tank -> Fuel manifold -> engine driven fuel pumps
If AC power is available before APU start, what happens?
The FWD left pump will automatically turn on, even if it wasn't selected
What does a green light on the NGS indicate?
The NGS is fully operational
What does an amber light or no light on the NGS indicate?
The NGS is inoperative.
What does a blue light on the NGS indicate?
The NGS is operational, but it is operating in a degraded condition.
What does the VALVE light inside the FUEL CROSSFEED switch indicate?
The crossfeed valve is not in the commanded position
Where is fuel temp taken from?
The left tank
What occurs if the center tank is below 1200 lbs and the main tanks drop below 50% useable fuel?
The pumps in the center tank will transfer the remaining fuel to the main tanks
Assuming all systems are working normally, what occurs if fuel is sent to the surge tanks during refueling?
The refueling shutoff valves are all closed automatically
What is the purpose of the surge tanks?
They accept excess fuel due to tank overfilling or thermal expansion, fuel then drains back into the center tank.
What occurs to the center tank pumps when the engines are below 50% N2?
They are inhibited
When is the center tank fuel pump inhibit removed with engines below 50% N2?
When the fueling station door is open so that the pumps can function and pump fuel out of the center tank if needed
When does fuel scavenging begin?
When the main tanks are approximately half empty
Are the totalizer and FMC fuel always the same number?
Yes
Can you dump fuel while on the ground?
Yes
Is it possible to jettison all center tank fuel and still be overweight?
Yes
What is the purpose of the DC electric motor in the left tank?
to provide fuel pressure to the APU when AC power is not available
