TM 55-1510-215-10
(1) Auxiliary fuel pump switches .
Two
annunciator panel (fig. 2-22).
switches, placarded AUX PUMP ON and OFF, located
on the fuel management panel (fig. 2-12) control a
NOTE
submerged fuel pump located in the corresponding
nacelle tank. During normal aircraft operation both
The L or R FUEL XFR light will also
switches are OFF (except during takeoff, landing or
serve as an operation indicator for
crossfeed, refer to chapter 9) so long as the engine-
the designated transfer pump. If the
driven boost pumps function. The loss of fuel pressure,
light illuminates, and the respective
due to failure of an engine driven boast pump will initiate
wing tank gage does not show
two flashing MASTER CAUTION lights on the instrument
empty, the transfer pump has
panel and will illuminate the yellow L FUEL FAIL or R
stopped transferring fuel into the
FUEL FAIL on the caution annunciator panel (fig. 2-22).
nacelle tank.
A positive transfer
Turning ON the AUX FUEL PUMP will extinguish the
pump test (as accomplished in
FUEL FAIL lights. The MASTER CAUTION lights must
be manually turned off.
without fuel transfer indicates a
nacelle tank fuel quantity sensor
(2) Fuel transfer pump switches .
Two
failure. Holding the TRANSFER TEST
switches on the fuel management panel (fig. 2-12),
switch to ON will override the fuel
placarded TRANSFER PUMP, ON and OFF control
quantity sensors and allow transfer
arming of the fuel transfer pumps in the normal mode.
of the remaining fuel. The L or R
During normal operation both switches are on, which
FUEL XFR light may be extinguished
allows the pump to be automatically turned off and on by
by turning the TRANSFER PUMP
a quantity sensor located in each nacelle tank. If either
switch to off.
transfer pump fails to operate when switched ON and
triggered to function by its quantity sensor, the fault
(5) Fuel crossfeed switch. The fuel crossfeed
condition is indicated by two flashing MASTER
valve (fig. 2-13) is controlled by a two position switch
CAUTION lights on the instrument panel and a steadily
illuminated yellow FUEL XFR light on the caution
placarded OPEN, and CLOSED. Under normal flight
annunciator panel (fig. 2-22).
conditions the switch is left in the CLOSED position. For
crossfeed system operation, refer to chapter 9.
(3) Fuel transfer test switch.
A switch,
Crossfeed operation is indicated by the illumination of
placarded TRANSFER TEST (fig. 2-12) on the fuel
the yellow FUEL CROSSFEED indicator light on the
management panel provides a means of checking the
caution annunciator panel (fig. 2-22), when the switch is
operation of either fuel transfer system. This switch is a
placed in the OPEN position. The crossfeed valve is
three-position toggle type, spring-loaded to the OFF
protected by a 5-ampere circuit breaker placarded
(center) position. When positioned to either L (left) or R
CROSSFEED VALVE located on the fuel system circuit
(right) the switch applies power to the selected transfer
breaker panel (fig. 2-22).
pump by bypassing the normal automatic circuit. If the
nacelle tank is full, the selected transfer pump will be
(6) Fuel crossfeed indicator light . Illumination
energized momentarily, which is enough to establish the
of the yellow FUEL CROSSFEED indicator light on the
operating status of that transfer system, indicated by the
caution annunciator panel (fig. 2-22) indicates that the
momentary flash of a yellow L FUEL XFR or R FUEL
electrically operated crossfeed valve is open.
XFR indicator light on the caution annunciator panel
NOTE
(4) Fuel transfer indicator lights. When all
The fuel crossfeed light may remain
usable fuel has been transferred from a wing tank
illuminated if the crossfeed valve
system, a sensing switch detects the pressure drop in
closes due to malfunction. The same
the fuel transfer line. After 30 seconds the affected
circuit that opens the crossfeed valve
transfer pump is shut off. This will illuminate the flashing
also illuminates the fuel crossfeed
MASTER CAUTION lights (fig. 2-22) and the appropriate
light.
yellow L or R FUEL XFR indicator light on the caution
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