TM 55-1520-228-10
d. The OH-58A/C, in its typical mission configura-
tion, is closer to its maximum gross weight th an most
other aircraft in the Army inventory; thus, the pilot is
consistently operating closer to power and directional
control limits. For this reason, the aircraft heading
should be ke pt in to the wind as mu ch as p ossible; it is
very important that precise heading control be main-
tained to minimize the yaw excursions that could lead
to LTE. Additionally, it has been determined that there is
a greater susceptibility to LTE for right turns (especially
right downwind turns at low altitude and low airspeeds)
than for left turns. Therefore, pilot should exercise
caution when executing right turns under conditions
conducive to LTE.
SECTION V. ADVERSE ENVIRONMENTAL CONDITIONS
8-33. GENERAL
This section provides information relative to operation
under adverse environmental conditions. Section II
checklist provides for operational requirements o
fthis
section. Refer to FM 1-202, Environmental Flight.
8-34. COLD W EATHER OPERATIONS.
Operation of the helicopter in cold weather or an arctic
environment presents no unusual problems if
the oper-
ators a re aware of those changes that do take place and
conditions that may exist because of the lower temper-
atures and freezing moisture.
a. Inspection. The pilot must be more thorough in
the preflight check, when temperatures have been at or
below 0 degrees C (32 degrees F). Water and snow may
have entered many parts during operations or in peri-
ods when the helicopter was parked unsheltered. This
moisture often remains to form ice w h ich will immobi-
lize moving parts or damage structure by expansion and
will occasionally foul electric circuitry. Protective covers
afford protection against rain, freezing rain, sleet, and
snow, when installed on a dry helicopter prior to the pre-
cipitation. Since it is not practicable to completely cover
an uns heltered he licopter, those parts not protected by
covers and those adjacent to cover overlap and joints
require closer attention, espe cia lly after blowing snow
or freezing rain. Remove accumulation of snow and ice
prior to fl ight. Failure to do so can result in hazardous
flight, due to aerodynamic and center-of-gravity distur-
bances, as well as the introduction of snow, water, and
ice into internal moving parts and elect rical systems. Pi-
lot should be particularly attentive to the main and tail
rotor systems and their e xposes control linkages.
b. Checks.
(1) Exterior checks 0 degrees C (32 degrees F)
to -54°C (-65°F) Perform exterior check as outlined in
Section II plus the following checks.
Check that all surfaces and controls are free of
ice and snow.
NOTE
Contraction of the fluids in the helicopter sys-
tem at extreme lo w temperature causes indi-
cation of low levels. A check made just af-
ter the previous shutdown and carried forward
to the walk-around check is satisfactory, if no
leaks are in evidence. Filling, when the sys-
tem is cold-soaked, reveals an over full condi-
tion immediately after fligh t, with the possibility
of forced leaks at seals.
(a) Main rotor. Check free of ice, frost, and
snow.
(b) Engine.
1
Inspect inlet for possible accumulations
of snow, slush, or ice. Accumulations must be removed
from the interior of the reverse flow inlet (hand removal
is acceptable).
2
Inspect the engine plenum chamber
through the plexiglass windows (a flashlight may be
required) on each side of the inlet cowling for snow,
slush, or ice, paying particular attention to the firewalls ,
rear face of the particle separator, bottom corners, and
protruding surfaces, such as guide vanes, etc.
3
Visually inspect the plastic particle sepa-
rator ejector tubes on each side of the engine fairing for
obstructions and snow. A thin film of ice about the inte-
rior of each tube is acceptable. External ice, adjacent to
the ejector tube, is acceptable.
8-14 Change 14
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