TM 55-1510-222-10
Table 2-2. Usable Fuel Quantity Data
TANKS
NUMBER
GALLONS
LEFT ENGINE
Main Tanks
6
192
Auxiliary Tank
1
78
RIGHT ENGINE
Main Tanks
6
192
Auxiliary Tank
1
78
*TOTALS
14
540
*Unusable fuel quantity not included in totals.
BT00102
Section IV. FUEL SYSTEM
2-32. FUEL SUPPLY SYSTEM.
The engine fuel supply system (fig. 2-15) consists
of two identical systems sharing a common fuel
management panel (fig. 2-16) and fuel crossfeed
plumbing (fig. 2-17). Each main fuel system consists of
five interconnected wing tanks, and a nacelle tank.
Each auxiliary fuel system consists of one tank located
between the nacelle and the fuselage. A fuel transfer
pump is located within each auxiliary tank. Additionally,
the system has an engine-driven boost pump, a standby
fuel pump located within each nacelle tank, a fuel heater
(engine oil-to-fuel heat exchanger unit), a tank vent
system, a tank vent heating system and interconnecting
wiring and plumbing. Total fuel tank capacity is shown
in Table 2-2. Gravity feed fuel flow is shown in figure 2-
18.
a.
Engine Driven Boost Pumps.
CAUTION
Engine operation using only the
engine-driven
primary
(high
pressure) fuel pump without standby
pump or engine-driven boost pump
fuel
pressure
is
limited
to
10
cumulative hours. This condition is
indicated by illumination of either the
#1 or #2 FUEL PRESS warning
annunciator and the simultaneous
illumination
of
both
MASTER
WARNING annunciators. All time in
this category shall be entered on DA
Form 2408-13 for the attention of
maintenance personnel.
A gear-driven boost pump, mounted on each
engine supplies fuel under pressure to the inlet of the
engine-driven primary high-pressure pump for engine
starting and all normal operations. Either the engine-
driven boost pump or standby pump is capable of
supplying sufficient pressure to the engine- driven
primary high-pressure pump and thus maintain normal
engine operation.
b. Standby Fuel Pumps. A submerged,
electrically-operated standby fuel pump, located within
each nacelle tank, serves as a backup unit for the
engine-driven boost pump. The standby pumps are
switched off during normal system operations. A
standby fuel pump will be operated during crossfeed
operation to pump fuel from one system to the oppo-site
engine. The correct pump is automatically selected
when the CROSSFEED switch is activated. Each
standby fuel pump has an inertia switch included in the
power supply circuit. When subjected to a 5 to 6 g
shock loading, as in a crash situation, the inertia switch
will remove electrical power from the standby fuel
pumps. The standby fuel pumps are protected by two
10-ampere circuit breakers placarded STANDBY PUMP
#1 or #2, located in the overhead circuit breaker panel
(fig. 2-6), and four 5-ampere circuit breakers (two each
in parallel) on the hot battery bus.
c. Fuel Transfer Pumps. The auxiliary tank fuel
transfer system automatically transfers the fuel from the
auxiliary tank to the nacelle tank without pilot action.
Motive flow to a jet pump mounted in the auxiliary tank
sump is obtained from the engine fuel plumbing system
downstream from the engine driven boost pump and
routed through the transfer control motive flow valve.
The motive flow valve is energized to the open position
by the control system to transfer auxiliary fuel to the
nacelle tank to be consumed by the engine during the
initial portion of the flight. When an engine is started,
pressure at the engine driven boost pump closes a
pressure switch, which after a 30 to 50 second time
delay to avoid
2-32
