STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS
Two electric pumps are used to transfer fuel from the mid-fuselage tanks into the wing tanks.
These pumps operate continuously as long as fuel is available in the mid tanks. When the fuel
level within the tank reaches a level slightly above empty and the line pressure drops to
5.0 + 0.5 psi, a signal is sent to the pump terminating operation.
Transfer Jet Pumps
Two transfer jet pumps are used to maintain fuel quantity in each feed chamber. These pumps
draw fuel into the feed chamber from the surrounding inboard bay of the wing tank.
Primary Jet Pumps
One primary jet pump is located in each fuel feed chamber. The primary jet pumps supply fuel
under pressure to the engines through the fuel feed line. An engine-driven fuel pump (located at
each engine) is connected to the primary motive flow line to initiate motive flow.
Engine-Driven Fuel Pumps
The fuel system uses two engine-driven pumps, one at each engine. These pumps initiate motive
flow as the engine starts by pumping fuel into the motive flow return line. This line then
supplies the motive flow to start/maintain primary jet pump operation.
405. FUEL MANAGEMENT SUBSYSTEM
During normal fuel feed operations, fuel gravity-flows into the mid fuselage tanks from the aft
tanks and is transferred from the mid tanks to the wing tanks by electric transfer pumps. Full
fuel condition in the wings and working pressure is maintained by the electric transfer pumps in
the respective mid tanks. Two pressure relief valves are provided in each wing tank to prevent
excessive wing overpressure.
The system includes caution or warning annunciator lights on the main annunciator panel for fuel
system malfunction. These lights include:
Annunciation of low fuel pressure to the engine
Low fuel in the feed chamber
Wing fuel level low
Low transfer pressure
Fuel filter bypass
FUEL SUPPLY SYSTEM