tm 1-1520-240-10 technical manual operator's manual for army ch ...

8-4-17. Before Leaving Helicopter.
If the helicopter is to be parked outside for extended
periods, maintenance personnel should install all protective
covers and secure the rotor blades. When ambient
temperatures of –18C and below are expected and the
helicopter is to be parked outside, maintenance personnel
should also remove the battery and store it in a warm
area until required for further operation.
8-4-18. Desert and Hot Weather Operation.
Refer to FM 1-202, Environmental Flight.
8-4-19. General.
The reduction in power available and the resulting decrease
in helicopter performance caused by reduced air
density and EAPS is the main consideration during desert
and hot weather operation. Therefore, greater emphasis
must be placed on determining performance during
mission planning.
8-4-20. Preparation for Flight.
A normal preflight inspection is to be conducted as described
in section II. Extra emphasis should be placed on
equipment which may be affected by higher temperatures,
such as tires, seals and hydraulic components. In
addition, check equipment for signs of deterioration or
excessive abrasion from blowing dust or sand. Windows
and doors should be opened to provide increased ventilation.
8-4-21. Engine Starting.
The normal engine starting procedures in section II are
to be used.
8-4-22. Taxiing.
Braking should be kept to a minimum to prevent overheating.
Ground operation in general should be kept to a
minimum.
8-4-23. Takeoff, Climb, Cruise, and Descent.
Helicopter performance may be reduced; therefore techniques
should be adjusted accordingly.
8-4-24. Landing.
The landing procedures in Section II apply. Braking
should be kept to a minimum to prevent overheating.
8-4-25. Engine Shutdown.
It may be necessary to motor the engines if temperature
does not decrease below 350C. It may not be possible
to lower the temperature to 260C. If the temperature will
not decrease below 260C, terminate motoring when the
temperature indication stabilizes.
TM 1-1520-240-10
NOTE
Pilots should make an attempt to avoid motoring
periods in excess of 15 seconds.
8-4-26. Before Leaving the Aircraft.
Leave all windows and doors open to increase ventilation,
except during conditions of blowing dust or sand.
8-4-27. Turbulence and Thunderstorm Operation.
8-4-28. Prior to Entering Turbulent Air.
CAUTION
To prevent engine overtorque, do not enter
forecast moderate or stronger turbulence
with the thrust brake (portion of the CCDA)
inoperative or BARO ALT engaged.
Prior to entering moderate or stronger turbulent air, the
following should be accomplished:
1. BARO ALT switch — Disengaged.
2. Crew — Alert.
3. Airspeed — Adjust as follows:.
a. In severe turbulence, decrease airspeed
to Vne minus 15 knots or to
maximum range, whichever is slower.
(Refer to Chapter 7.)
b. In moderate turbulence, decrease air
speed to Vne minus 10 knots or to maxi
mum range, whichever is slower. (Refer
to chapter 7.)
4. Longitudinal cyclic trim — Select MAN, then
adjust both actuators for the airspeed to be
flown. This is accomplished to prevent the
cyclic trim actuators from cycling.
5. Loose equipment — Secure.
6. Safety belts and shoulder harneses —
Tighten.
8-4-29. In Turbulent Air.
The thrust control position, when adjusted for the airspeeds
mentioned above, should be maintained and the
attitude indicator should be used as the primary pitch
instrument. The altimeter and vertical velocity indicator
may vary excessively in turbulence and should not be
relied upon. Airspeed may vary as much as 40 knots. By
maintaining a constant thrust control position and a level
flight attitude on the attitude indicator, airspeed will remain
relatively constant even when erroneous readings
are presented by the airspeed indicator.
8-4-3