8-69. COLD WEATHER OPERATIONS.
Operation of the surface deice system in
ambient temperatures below -40°C can
cause permanent damage to the deice
boots. Operational diffIculties may be
encountered during extremely cold
weather, unless proper steps are taken
prior to or immediately after flight. All
personnel should understand and be fully
aware of the necessary procedures and
a. Preparation For Flight. Accumulations of
snow, ice, or frost on aircraft surfaces will adversely
affect takeoff distance, climb performance and stall
speeds to a dangerous degree. Such accumulations
must be removed before flight. In addition to the
normal exterior checks, following the removal of ice,
snow, or frost, inspect wing and empennage surfaces
to verify that these remain sufficiently cleared. Also,
move all control surfaces to confirm full freedom of
movement. Assure that tires are not frozen to wheel
chocks or to the ground. Use ground heaters, anti-
ice solution, or brake deice, to free frozen tires.
When heat is applied to release tires, the tempera-
ture should not exceed 71 °C (160°F). Refer to Chap-
ter 2 for anti-icing, deicing, and defrosting treat-
Engine Starting. When starting engines on
ramps covered with ice, propeller levers should be in
the FEATHER position to prevent the tires from
sliding. To prevent exceeding torque limits when
advancing CONDITION levers to HIGH IDLE dur-
ing the starting procedure, place the power lever in
BETA and the propeller lever in HIGH RPM before
advancing the condition lever to HI IDLE.
Warm-Up and Ground Test. Warm-up pro-
cedures and ground test are the same as those out-
lined in Section II.
d. Taxiing. Whenever possible, taxiing in
deep snow, light weight dry snow or slush should be
avoided, particularly in colder OAT conditions. If it
is necessary to taxi through snow or slush, do not set
the parking brake when stopped. If possible, do not
park the aircraft in snow or slush deep enough to
reach the brake assemblies. Chocks or sandbags
should be used to prevent the aircraft from rolling
while parked. Before attempting to taxi, activate the
brake deice system, insuring that the bleed air valves
are OPEN and that the condition levers are in HI
IDLE. An outside observer should visually check
wheel rotation to insure brake assemblies have been
deiced. The condition levers may be returned to
LOW IDLE as soon as the brakes are free of ice.
e. Before Takeoff.
If icing conditions are expected, acti-
vate all anti-ice systems before takeoff, allowing suf-
ficient time for the equipment to become effective.
If the possibility of ice accumulation
on the horizontal stabilizer or elevator exists, takeoff
will not be attempted. If icing conditions are
expected, activate all anti-ice systems before takeoff,
allowing sufficient time for the equipment to
f. Takeoff. Takeoff procedures for cold
weather operations are the same as for normal take-
off. Taking off with temperatures at or below freez-
ing, with water, slush or snow on the runway, can
cause ice to accumulate on the landing gear and can
throw ice into the wheel well areas. Such takeoffs
shall be made with brake deice on and with the ice
vanes extended to preclude the possibility of ice
build-up on engine air inlets. Monitor oil tempera-
tures to insure operation within limits. Before flight
into icing conditions, the pilot and copilot WSHLD
ANTI-ICE switches should be set at NORMAL posi-
g. During Flight.
Brake deice. After takeoff from a run-
way covered with snow or slush, it may be advisable
to leave brake deice ON to dislodge ice accumulated
from the spray of slush or water. Monitor BRAKE
DE-ICE annunciator for automatic termination of
system operation and then turn the switch OFF.
(2.) Flight controls. During flight, trim
tabs and controls should also be exercised periodi-
cally to prevent freezing.
Anti-icing equipment. Insure that anti-
icing systems are activated before entering icing con-
ditions. Do not activate the surface deice system
until ice has accumulated one-half to one inch. The
propeller deice system operates effectively as an
anti-ice system and it may be operated continuously
in flight. If propeller imbalance due to ice does
occur, it may be relieved by increasing RPM briefly,
then returning to desired setting.