Growler systems: Fuel

2 and 3

1, 4, and wing tanks

normally separated but can be interconnected by a normally closed crossfeed valve and a normally closed feed tank interconnect valve.

• a. airframe mounted accessory drive (AMAD) driven motive flow/boost pump
• b. feed tank with an internal motive flow powered turbo pump
• c. engine feed shutoff valve

two‐stage motive flow/boost pump. The first stage supplies low pressure fuel to its respective engine mounted fuel pump, while the second stage supplies high pressure fuel to the motive flow system

Each feed tank has a horizontal baffle which traps fuel, providing a minimum of 10 seconds of negative g flight at MAX power. No sustained zero g capability is provided, and prolonged transitions through zero g (greater than 2 seconds) may produce a L and/or R BOOST LO caution

fuel is suction fed to the motive flow/boost pump. In this case, flight at high altitude with high feed tank fuel temperatures may not supply enough fuel for high power settings.

electrically closes the corresponding engine feed shutoff valve, isolating that fuel feed system

normally closed, allows a single motive flow/boost pump to feed both engines when boostpressure is lost on one side

at least MIL power

During normal operation, the dual flapper‐type valve is held closed by motive flow pressure on either side (left motive flow on the tank 2 side and right motive flow on the tank 3 side), and no fuel gravity transfers.

1. designed to keep tanks 2 and 3 within 100 lb of each other

2. balancing begins after tank 4 is effectively empty (less than about 300 lb) and the feed tanks begin to deplete below full

3. If a feed tank imbalance reaches 100 lb, the SDC shuts off the corresponding tank 4 scavenge pump until the imbalance is 50 lb in the opposite direction

4. Feed tank balancing stops at FUEL LO to make sure tank 4 fuel is transferred to both feed tanks in case one feed tank is damaged and is leaking.

5. After transitioning to WonW, balancing is reinitiated and continues until either feed tank is below 300 lb.

feed tank balancing begins when either feed tank drops below approximately 2,100 lb for 1 minute

When driven by an idling engine, a motive flow/boost pump can support fuel flow up to 28,000 pph through the crossfeed valve (MIL power fuel flow is approximately 12,000 pph at sea level, standard day). If the fuel flow demand on the usable engine exceeds 28,000 pph (midrange afterburner), motive flow/boost pump output pressure drops,setting the other BOOST LO caution, closing the crossfeed valve, and starving the good engine. MAX power, single engine fuel flow is approximately 38,500 pph at sea level, Mach 0.2, standard day (approach conditions).

28,000

shutdown the idling engine. This opens both the interconnect and crossfeed valves.

two dual‐speed electric transfer pumps

afterburner operation, ARS replenishment, or fuel dump

two motive flow powered scavenge pumps, one routed to tank 2 and the other to tank 3

when tank 1 and 4 fuel is not scheduling properly or wing tank imbalance exceeds 350 lb. The caution is inhibited when the inflight refueling probe is extended.

two motive flow powered ejector pumps, one in each tank.

2,200

• a. PROBE switch in EXTEND
• b. both HOOK and LDG GEAR handles down

prevents transfer and refueling of controlled external tank(s) except with a FUEL LO caution

The internal fuel tank pressurization system provides ram air from the vertical tail vents to all internal tanks to prevent fuel boil‐off at altitude.

fuel flows through the vent lines to the fuselage vent tanks. Two motive flow powered vent tank scavenge pumps return this fuel from the fuselage vent tanks to the feed tanks.

The thermal management system uses fuel from the high pressure fuel stage of the motive flow/boost pump to cool the FADECs, liquid coolant, AMAD, and hydraulic oils

1. used to run motive flow powered pumps and valves in the fuel system

2. directs cooling flow to the FADEC and exits into the fuel recirculation return line

3. runs through the liquid coolant/fuel heat exchanger and the combined AMAD oil and hydraulic oil/fuel heat exchanger in order to cool those fluids. A hot fuel diverter valve in the third branch either directs fuel away from the engine and into the fuel recirculation return line or directs fuel to the engines where it is combined with fuel feed from the motive flow/boost pump and burned.

4. runs to the cross cooling valve which opens following a motive flow system failure, allowing one motive flow system to cool both FADECs and both engines' accessories.

engine fuel control unit, maintains engine combustor nozzle, engine lube oil, and aircraft accessories within their temperature limits

the liquid coolant pump and liquid cooling system (LCS) ground cooling fan may be commanded on (if not already on) to provide LCS cooling of the fuel system. The ECS controller will only direct liquid coolant to the liquid coolant/fuel heat exchanger if the RADAR knob is in OFF.

above each engine inlet, near the leading edge.

the SDC closes the heat exchanger bypass valve and isolates the heat exchanger.

the heat exchanger uses inlet air to provide additional fuel cooling.

400.

below approximately Mach 0.35 and anytime the ECS auxiliary scoops are deployed to guard against potential for engine inlet fuel ingestion.

HYD 2B or APU accumulator

feed tank fuel

1,300 lb per minute (78,000 pph)

• 1. The DUMP switch is placed to OFF.
• 2. The BINGO caution comes on.
• 3. Tanks 1 and 4 are empty and all available fuel from internal wing and external tanks has been depleted.
• 4. The FUEL LO caution comes on.

during high alpha maneuvering may ignite the fuel mist causing extensive damage or loss of aircraft.

inadvertently move the fuel DUMP switch from the OFF to ON position during normal throttle movements.

there are none

the tank 1 and 4 transfer line

• JP-5: 1,430 
• JP-8: 1,410

• JP-5: 2,660
• JP-8: 2,610

• JP-5: 2,680
• JP-8: 2,640

• JP-5: 3,860
• JP-8: 3,810

• JP-5: 10,630
• JP-8: 10,470

• JP-5: 1,670
• JP-8: 1,650

• JP-5: 13,970
• JP-8: 13,770

• JP-5: 3,220
• JP-8: 3,170

13 seconds

completely independent

When the fuel level in either feed tank drops to approximately 1,125 lb, a FUEL LO caution, caution light, and voice alert are activated, and the affected fuel tank quantity is displayed in inverse video on the EFD.

60 seconds