HEADQUARTERS OH-58A, Technical Manual

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TM 55-1520-228-10
2-24. CONTROLS AND INDICATORS.
a. Fuel Quantity Indicator. The FUEL QTY indi-
cator (figure 2-13 and 2-14) is located in the instrument
panel and displays the quantity of fuel in the fuel cell in
pounds (0 to 600 lbs.). The indicator is powered by 28
Vdc and protect by INST CLUSTER circuit breaker ,
FUEL QTY circuit breaker .
b. Fuel Boost Caution Light. The FUEL BOOST
caution light (figure 2-13 and 2-14) is located on the cau-
tion panel and illuminates if the fuel boost pressure is
below safe operating limits when fuel boost switch is in
the ON position. The system is powered by 28 Vdc and
protected by CAUTION PANEL LTS circuit breaker.
c. Fuel Boost Pump Switch. The FUEL BOOST
switch (figure 2-13 and figure 2-14) is located in the
lower right corner of the instrument panel. The fuel boost
switch will be in the fuel boost position for all normal
conditions when the engine is operating and for start-
ing. The system is powered by 28 Vdc and protected by
FUEL PUMP circuit breaker.
NOTE
Low fuel caution systems alert the pilot that fuel
in the tank has reached a specified level (capac-
ity). Differences in fuel densities due to temper-
ature and fuel type will vary the weight of fuel
remaining and actual time aircraft engine may
operate. Differences in fuel consumption rates,
aircraft altitude and operational condition of the
fuel subsystem will also affect actual time air-
craft engine may operate.
d. Low Fuel Quantity Caution Light. The LOW
FUEL caution light, (figure 2-13 and figure 2-14), located
in caution panel, should illuminate when there is approx-
imately 20 minutes or 65 to 98 pounds of fuel remaining.
The illumination of this light does not mean a fixed time
remains. When the 20 minute fuel caution light is on, the
fuel remaining may not be available except when the air-
craft is in level or coordinated flight. The 20 minute fuel
caution light in conjunction with a fuel boost caution light
may indicate impending fuel starvation. The system is
powered by 28 VDC and projected by Caution PNL LTS
circuit breaker.
e. Fuel Filter Caution Light. The FUEL FILTER
caution light (figure 2-13 and figure 2-14), located in the
caution panel, will illuminate when the filter in the fuel
supply line becomes partially obstructed. The system
is powered by 28 Vdc and protected by CAUTION PNL
LTS circuit breaker. The light may illuminate momen-
tarily when the boost pump is turned on, but it should
extinguish within approximately ten seconds.
SECTION V. FLIGHT CONTROLS
2-25. DESCRIPTION.
When carrying non-rated passengers unfamil-
iar with operation of the helicopter, pilot should
evaluate the mission as to advantages and dis-
advantages of stowing copilot controls or ac-
cepting the responsibility of the potential hazard
when leaving the controls in place.
The flight control system is a positive mechanical type,
actuated by conventional helicopter controls which,
when moved, directs the helicopter in various modes
of flight. Dual flight controls are provided. The system
includes; the cyclic control stick, used for fore and aft
and lateral control; the collective pitch control lever,
used for vertical control; and the tail rotor anti-torque
control pedals, used for heading control. The con-
trol forces of the main rotor flight control system are
reduced to a near zero pounds force, to lessen pilot
fatigue, by hydraulic servo cylinders connected to the
control system mechanical linkage and powered by
the transmission driven hydraulic pump.
Force trims
(force gradients) connected to the cyclic controls are
electrically operated mechanical units used to induce
artificial control feeling into the cyclic controls and to
prevent the cyclic stick moving from a pre-set position.
2-26. CYCLIC CONTROL.
The pilot cyclic grip (figures 2-3 and 2-4) contains the fol-
lowing switches: force trim release switch, ICS switch,
and RADIO transmit switch. The cyclic control system
controls the fore, aft, and lateral movement of the heli-
copter. Control feel is provided by the force trim units.
2-30 Change 1
4