2.36.3 Fuel Quantity Indicators.
The pilot vertical-
scale fuel quantity indicator (fig 5-1) indicates the quantity
(in pounds X 10) of fuel remaining in the forward and aft
fuel cells. A digital display at the bottom of the indicator
shows the combined total of remaining fuel (in pounds X
10). The CPG selectable digital display (SDD) indicates
the pounds of fuel remaining in the forward and aft fuel
cells. The SELECT knob is rotated until the FUEL QTY X
10 display is illuminated thus causing the pounds of fuel
remaining in each cell to appear on the digital display.
Combined total fuel is not indicated. The fuel quantity
transmitters are capacitance-type transmitters. There are
three fuel quantity transmitters: two are in the forward fuel
cell because of the shape of the fuel cell, and one is in the
aft fuel cell. The transmitters provide data to the fuel signal
conditioner which, in turn, provides a readout to the fuel
quantity indicators in the crew stations.
2.36.4 Fuel System Caution/Warning Lights.
system caution/warning segments on the caution/warning
panel are discussed in Section XIV, (tables 2-4 and 2-5).
Their positions are shown on the caution/warning panel
2.36.5 Auxiliary Fuel Tank.
For ferry missions, there
are provisions for as many as four external fuel tanks to be
carried on the wing pylon attachment points. The external
tanks can be jettisoned in the same manner as any other
externally mounted stores.
2.36.6 Refueling Provisions.
All fuel service points
are located on the right side of the helicopter. For all re-
fueling operations, the REFUEL valve switch must be
placed in the OPEN position and then CLOSED after
completion of refueling. Section XV contains fuel specifi-
cations and weights. Chapter 6 describes the effects of
fuel loading on weight and balance.
a. Gravity Filling.
The forward and aft cells and the
external auxiliary tanks are gravity-filled separately. Fuel
cell filler ports are located forward and aft of the wing. Re-
fueling time required for gravity refueling depends on the
flow-rate capability of the servicing equipment. Section
XV contains specific filling procedures.
For gravity refueling, the closed vent system
requires the refuel valve to be open to obtain
maximum fill above the opening of the filler
neck. When fuel has reached this level, the
fuel flow rate will have to be decreased to
accommodate the restricted vent flow rate.
b. Pressure Refueling.
The pressure service man-
ifold, located forward of the right wing, has two adapters
for accommodating either a single point adapter (SPA) or
a closed-circuit adapter (CCA). Using either nozzle, for-
ward and aft cells may be filled separately or simulta-
neously dependent upon the refueling panel switch set-
tings (fig 2-45). The shutoff valve at the bottom of each
fuel cell responds to an adjoining float-type pilot valve at
the top of the cell. This valve will automatically stop fuel
flow when the cell is full. Shutoff is set to allow space for a
3% expansion in each cell. The IND switch to the left of the
FUEL QTY indicator on the refueling panel energizes the
quantity indicator and advisory lights. After refueling, the
REFUEL VALVE switch must be returned to the CLOSED
position, or fuel transfer from cell-to-cell cannot be accom-
plished by either crewmember. The inside panel of the re-
fueling panel access door contains servicing instructions.
Section XV contains complete pressure refueling proce-
2.36.7 APU Fuel Supply.
The APU receives fuel from
the aft fuel cell. Fuel is routed from the aft fuel cell through
the APU fuel shutoff valve to the APU boost pump and on
to the APU.
a. APU Fuel Shutoff Valve.
The APU fuel shutoff
valve is controlled by the APU OFF,-RUN, and,-START
switch When the switch is moved to the RUN position, the
shutoff valve is electrically opened to allow fuel flow to the
APU boost pump. If the FIRE APU PULL handle is pulled,
the APU fuel shutoff valve will close.
b. APU Boost Pump.
The electrically-driven APU
boost pump is energized when the APU START/RUN
switch is at the START or RUN position. The pump will
continue to run until the APU is shut down. The pump de-
livers fuel to the APU integral fuel shutoff valve. Pulling the
FIRE APU PULL handle will stop the pump.