曝光台 注意防骗
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cell. Both engines will feed from either the FWD TK or
AFT TK when selected. This allows the pilot an emergency
means to continue fight to a safe area after sustaining
fuel system damage. The crossfeed switch can
still be used on the ground to control fuel feed during
hot refueling. CROSSFEED switch must be placed in
the NORM position at least 30 seconds prior to takeoff.
If the ENG 1 or ENG 2 fire pull handle is pulled, the
2-34 Change 2
TM 1-1520-238-10
selected engine crossfeed/shutoff valve automatically
closes.
Some helicopters have been modified with green and
amber crossfeed (X FEED) annunciator lights located
on the pilot and CPG caution/warning panels (fig
2-44.1). The green X FEED annunicator light will illuminate
on both caution/warning panels when crossfeed
is selected by the pilot and both engine fuel valves are
correctly positioned for the selection. The green X
FEED annunicator light will also illuminate when
override and crossfeed is selected by the CPG and both
valves are correctly positioned. When the CROSSFEED
switch on the pilot fuel control panel is placed in
the FWD TK or AFT TK position the X FEED caution/
warning lights will be inhibited for 3 ± 1 second while
the fuel valves move to their selected position. The amber
X FEED annunicator light and the MASTER
CAUTION light (fig 2-43) will illuminate on both caution/
warning panels when the pilot has selected crossfeed
or the CPG has selected override and one or both
fuel valves are incorrectly positioned. The amber X
FEED caution/warning lights will also illuminate
when a fuel valve is in the CLOSED position (in response
to actuation of a fire handle or pilot fuel control
panel ENG 1 or ENG 2 fuel switch in the OFF position.
NOTE
During engine start the amber X FEED
caution/warning lights will illuminate if
the CROSSFEED switch is not in the
AFT TK position.
c. External Tank Switch (EXT TK). The pilot activates
fuel transfer from as many as four external fuel
tanks to the internal fuel cells by positioning the EXT
TK switch to ON. The switch opens the auxiliary fuel
tank shutoff valve and the two transfer shutoff valves.
Opening the auxiliary fuel tank shutoff valve allows
pressurized air to force fuel from the left auxiliary fiel
tank into the forward Fuel cell and from the right auxiliary
fuel tank into the aft fuel cell. When all auxiliary
tanks are empty, the EXT EMP caution light on the pilot
caution/warning panel illuminates.
NOTE
l The REFUEL VALVE switch (located
on the external fuel servicing panel (fig
2-45) must be closed for operation of the
TRANS switch to be effective. The
transfer pump will not transfer fuel if
the refuel valve is open.
l The fuel transfer system is the primary
method of balancing loads.
d. Transfer Switch (TRANS). The TRANS switch
controls the position of the fuel transfer air valve. The
fuel transfer air valve directs pressurized air to the bidirectional
transfer pump which allows fuel transfer
between fuel cells. With the switch in the TO AFT or
TO FWD position, pressurized air is directed to the air
motor which turns the transfer pump and transfers fuel
forward or aft. If the transfer pump is transferring fuel
and the fuel cell to which it is transferring becomes full,
a fuel level control valve will shut off the fuel flow
through the pump. There is no need to stop the transferring
operation until the fuel cells are at the desired
level.
Some helicopters have been modified with green and
amber transfer (FUEL XFR) annunciator lights located
on the pilot and CPG caution/warning panels (fig
2-44.1). The green FUEL XFR annunicator light will
illuminate on both caution/warning panels when the pilot
or CPG fuel transfer switch is in the transfer position
and transfer occurs. The amber FUEL XFR annunicator
light and the MASTER CAUTION light (fig
2-43) will illuminate on both caution/warning panels
when the pilot or CPG fuel transfer switch is in the
transfer position and transfer does not occur.
The CROSSFEED switch shall be set
to the NORM position at all times unless
executing emergeney procedurea
for FUEL PSI ENG 1 and FUEL PSI
ENG 2. Using the fuel system crossfeed
may result in a dual engine
flameout if one of the engine fuel
valves fails to properly position.
e. BOOST Switch. The boost pump (located in the
aft fuel cell) is used for starting the engines and when
the FUEL PSI ENG 1 and FUEL PSI ENG 2 caution
lights illuminate. The BOOST switch electrically
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阿帕奇攻击直升机操作手册1(25)
