The system has two wing tanks and a collector tank.  The basic operation is that the wing tanks feed into the collector tank through use of transfer jet pumps.   From the collector tank, it proceeds to the engine via the fuel pickup valve.  A primary jet pump or electric boost pump in the collector tank sends the fuel to the engine-driven low pressure pump.  The fuel then proceeds to the engine-driven high pressure pump.  The fuel/air mixture is controlled by the FMU (fuel management unit).  The engine is fed if the aircraft is inverted because of the weighted "flip-flop" valve for a minimum of 15 seconds.  Wing tank fuel quantity is automatically balanced but the system also incorporated and means to manually balance the fuel quantities.  The normal quantity on the UPT sortie is 1100# which allows the plane to fly for approximately 3 hours.  UPT sorties are normally scheduled for a 1.3 so fuel is not usually the limfac in a training sortie.

Easy way to remember the fuel system numbers and functions:  7,6,5,4,3,2,2,1

7 – Fuel Probes

• 3/wing tank(Full, 445 ± 50#, 308 ± 50#

• 1/collector tank(40#)

6 – CWS indicators

RED(x1)

• FUEL PX (activates when pressure downstream of the low pressure engine driven pump (Motive Supply line) < 10psi

AMBER(x3)

• FUEL BALANCE (when the EDM cannot maintain < 30# imbalance longer than 2 minutes, or with Fuel Probe failure)

• L FUEL LO (when < 110# in left wing tank)

• R FUEL LO (when < 110# in right wing tank)

GREEN(x2)

• M FUEL BALANCE (whenever the Manual Fuel Balance switch(FCP) is set to MAN/RESET)

• BOOST PUMP (whenever the Boost Pump switch(F+RCP) set to on, whenever Motive Supply Line < 10psi, and when the Starter switch set to AUTO/RESET

5 – Motive Flow Pumps (driven by low pressure engine driven pump)

• 2/wing tank (transfer fuel to collector tank, pressurize collector to 1.0-1.5 psi)

• 1/collector tank (primary feed for low pressure engine driven pump through maintenance shutoff valve – fuel filter – firewall shutoff valve, attached to Flip-Flop Valve)

4 – Fuel Control Switches (can also include Starter switch if desired)

Front Cockpit

• Boost Pump – activates the Boost Pump

• Fuel Balance – Activates the Manual Fuel Balance select switch

• Manual Fuel Balance – L/R stops fuel flow from the selected tank by closing the Transfer Valve which provides motive flow to the Transfer Pumps.

Rear Cockpit

• Boost Pump – same as FCP

3 – Fuel Tanks

• Wing – 2 tanks hold 530/580# each(single point/over wing fueling respectively)

• Collector – 1 tank holds 40# (allows for inverted flight >15sec, fed by gravity feed(eg. Refueling), or motive flow from transfer pumps(eg. Inflight))

2 – Engine Driven Pumps

• Low Pressure fed by collector tank feeds Motive Flow pumps, Fuel Pressure switch, and High Pressure pump

• High Pressure fed by Low Pressure pump feeds FMU, Fuel flow transmitter, and engine can suction feed(10 hours) with failure of both boost pump and low pressure pump.failure will cause flameout and restart will be impossible.

2 – Shutoff Valves

• Maintenance – upstream of fuel filter, only accessible on the ground and allows maintenance to work on filter/motor.

• Firewall – activated by Firewall Shutoff Handle.

1 – Electric Boost Pump

• Activated when starter engaged, switched on manually, or when pressure <10psi in motive flow line.

Total Fuel – 1100# single point refueled (takes 3-5 minutes, cutoff check instant), 1200# overwing refueled

200# - Normal Recovery Fuel & Solo Student Min Fuel

150# - Dual Min Fuel

100 # - Emergency Fuel

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