Fuel System Flashcards
Fuel tanks
2 Feed tanks2 wing auxiliary tanks2 forward sponson tanks 1 aft sponson tankProvisions for up to 3 Mission Auxiliary Tanks
Type of fuel pumps
2 suction lift pumps one at each feed tank. Boost pumps which are normally used during refueling and fuel dumping are available to support the suction lift pumps in the event of a failure.
L/R Feed tank capacities
88 gallons (600 lbs)
L/R Wing Aux tank capacities
294 gallons (2000 lbs)
L/R Fwd Sponson tank capacities
478 gallons (3250 lbs)
R Aft Sponson tank Capacity (if installed)
301 gallons (2050 lbs)
Total capacity in normal configuration (L/R Feed, L/R Wing Aux, L/R Fwd Sponson tanks)
11,700 lbs
Quantities of MATS tanks based on 80% full for the forward and 75% full for the mid and aft tanks
Fwd - 345 gallons (2350 lbs)Mid - 324 gallons (2200 lbs)Aft - 324 gallons (2200 lbs)
MATS
Mission Auxiliary Tank System - Comprised of up to 3 430 gallon fuel tanks (Forward, Mid, and Aft tanks if installed)
OBIGGS
Onboard Inert Gas Generating System - Provides a nitrogen enriched atmosphere for fuel tank inerting which reduces tank vulnerability to fire and explosions attributable to ballistic impacts.
Which tanks are 100% self sealing
Wing feed tanks
How many fuel probes are there in each tank
There are two Fuel Quantity Probes in each Feed, Wing Auxiliary, and Forward Sponson Tank. There is only one Fuel Quantity Probe in each Mission Auxiliary Tank and the right Aft Sponson Tank.
Rupture Disks
Aluminum membranes that break and vent fuel overboard through vent lines if the tank is overfilled or if the tank is overpressurized (climb valve fails to open during ascent)
Climb/Dive Valves
As a fuel tank’s pressure increases or decreases due to altitude changes, the Climb/Dive Valves open to compensate
Sump Drain Valves
provided as a means of sampling fuel and defueling tanks by gravity
Negative Gravity Inlet Assemblies
Installed on the left and right Feed Tanks to provide 10 second supply of fuel to the engines during negative G maneuvers
FMU
Provide an interface to the aircraft pumps, valves, and quantity measurement system, and also perform monitoring using Built-In-Test (BIT) and fault annunciation.
How do you isolate tanks
Fuel status layer Menu 3, and Fuel status layer Menu 4 for MATS tanks
Fuel Burn Sequence
Right Aft Sponson (if installed)Aft Mission Aux (if installed)Mid Mission Aux (if installed)Fwd Mission Aux (if installed)L/R Wing AuxL/R Fwd SponsonL/R Wing Feed
When is the Cross Transfer Valve taken out of the AUTO mode
If there is a single FMU failure in which case it defaults to CLOS, or if it’s manually changed by the pilot.
When should the Cross Transfer Valve be manually placed in the OPEN mode
During Single engine operation select the XFER VALVE to OPEN and the Transfer Pumps (TPUMP BOOST) to ON to ensure fuel is made available to the operative engine and mitigate uneven fuel burn
Suction Transfer
Primary means of transferring fuel and the 2 suction lift pumps are automatically controlled by the FMUs
Where are boost pumps installed
Sponson Tanks, Wing Auxiliary Tanks, and MATS (if installed).
All fuel can be dumped except for ___
fuel in the feed tanks (unless the suction lift pump has failed)
Rate that fuel is dumped
Approximately 800 lbs per minute
Fuel Dump System utilizes____
all available boost pumps
Configuration for fuel dump
Cargo ramp door closedLanding gear up Main cabin door closed
Fuel dump altitude limitation
6000 ft AGL and above except for in an emergency
When will fuel dump automatically secure
approximately 70 seconds after usable fuel reaches 1700 lbs indicated
Where is the fuel dump panel located
overhead panel
When can fuel dump not be initiated
With a single FMU failure
How does an FMU failure affect the Fuel Transfer/Crossfeed System
When the Cross-Transfer Valve (XFER VALVE) is operating in the automatic (AUTO) mode, failure of an FMU will automatically set the XFER VALVE to the closed (CLOS) position. If the XFER VALVE is operating in the manually selected OPEN or CLOS position when the FMU failure occurs, it will remain in that selected position.
EARP
Emergency Aerial Refueling Panel - Located above the left hand avionics rack, used to manually open and close the refuel valves and pump bypass valves for the transfer tanks on the FMU failed side to facilitate or secure aerial refueling with an FMU failure.
Fuel Dump capability with single FMU failure
Fuel cannot be dumped with a single FMU failure
FEED TANK LOW Caution
Quantity below 550 lbs +/- 20 lbs or when gauged quantity reads 520 lbs
FEED TANK OVERFILL Caution
Quantity at 675 lbs
What triggers a FUEL TRAPPED Caution
FMU detects a FEED TANK LOW condition and fuel is not transferring from the tank that should be transferring
PRESSURE SOV IN TEST Advisory
Simply lets the crew that an automatic BIT of the Pressure Shut Off Valves has commenced. It may last as long as 15 minutes.
What conditions must be met for the Pressure Shutoff Valve test to begin
- BOTH engines running for more than 60 seconds2. BOTH engines burning more than 600 pph for at least 20 seconds