TM 55-1520-240-23-8
10-1
FUEL SYSTEM
(Continued)
10-1
ENGINE FUEL FEED SYSTEM
Engine fuel is supplied by the airframe fuel system. The
No. 1 (left) engine is supplied by the No. 1 (left) fuel
subsystem. The No. 2 (right) engine is supplied by the
No. 2 (right) fuel subsystem.
NO BREAK - WORK HARDER
The fuel passes through a breakaway fitting in the rear
wall of the main tank into the aft intertank area to a cross
connector on the fuselage.
NO BREAK - WORK HARDER
The cross connector directs fuel through the fuselage
and to a drain fitting on the bottom skin of the intertank
bay. The connector on the left side also directs fuel to
the APU and on the right side to the heater.
NO BREAK - WORK HARDER
Interconnecting the two engine fuel feed systems is
a fuel crossfeed line with two motor operated shutoff
valves. The crossfeed system allows fuel from one
system to supply both engines in case one system
becomes inoperative. The No. 2 system has a manually
operated valve for defueling purposes.
NO BREAK - WORK HARDER
The engine fuel passes a pressure switch, motor
operated valve, and fuel flow transducer before passing
through a fuselage quick-disconnect filling on the way to
the engine fuel boost pump.
NO BREAK - WORK HARDER
An engine feed suction line in each main tank works as
a backup system in case both main tank boost pumps
fail. When one main tank boost pump fails, the check
valve for that pump closes to prevent reverse flow, or air
being drawn into the engine feed line. When both boost
pumps fail, fuel is drawn by the engine fuel boost pump
through a separate hose in the main tank. Flight altitude
must not exceed 6000 feet in this condition.
10-12
