STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS
are located beneath the cabin floor, one adjacent to each wing. Each wing contains a single fuel
tank divided into three fuel bays. The inboard bay contains a specialized fuel feed chamber.
Vent surge tanks are located in each wing tip and in the aft fuselage. Two miniature holding
tanks (drain boxes) capture fuel drain at engine shutdown.
404. FUEL DISTRIBUTION SUBSYSTEM
Fuel will gravity-flow from the aft fuselage and aft cabin tanks into the mid tanks, and from the
outboard wing tank bays into the inboard bay. To provide reliable fuel transport for the entire
system, several types of pumps are used:
Electric pumps for boost and transfer
Motive flow jet pumps
Engine-driven fuel pumps
These pumps are used to transport the fuel from the mid tanks to the wing tanks, from the wing
tanks into the fuel feed chamber, and from the fuel feed chamber to the engines.
One electric boost pump is located in each fuel feed chamber. The boost pumps serve four
Backup for the primary jet pumps
Source of fuel pressure for operation of the two transfer jet pumps in each fuel feed
In the automatic mode, the boost pump will operate when:
Fuel feed line pressure drops below 5 psi
Fuel feed chamber volume falls below full
Engine starting is selected
Crossfeed is selected
FUEL SUPPLY SYSTEM