Section V. ADVERSE ENVIRONMENTAL CONDITIONS
The purpose of this section is to inform the pilot of
the special precautions and procedures to be followed
during the various weather conditions that may be
encountered in flight This section is primarily narrative,
only those checklists that cover specific procedures
characteristic of weather operations are included. The
8-48. COLD WEATHER OPERATIONS.
To ensure adequate bleed air pressure to
the deice boots, do not simultaneously
actuate the surface and antenna deice
systems in the manual mode.
Operation of the surface deice system in
ambient temperatures below -40 ° C can
cause permanent damage to the deice
Under conditions where one bleed air
source is inoperative, sufficient bleed air
pressure for deice boot inflation may not be
available. Prior to deice boot inflation,
check the regulated bleed air pressure gage
for a minimum of 16 PSI. If insufficient
pressure exists, increasing engine N, and/or
decreasing aircraft altitude will increase
bleed air pressure.
Operational difficulties mav 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 precautions involved.
Preparation For Flight. Accumulations of
snow, ice, or frost on aircraft surfaces will adversely
affect takeoff distance, climb performance, and stall
speed 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
Ensure 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 temperature should not exceed 71° C
(160° F). Refer Chapter 2 for anti-icing, deicing, and
Engine Starting. When starting engines on
ramps covered with ice, PROP levers should be in the
FEATHER position to prevent the tires from sliding.
Warm-up and Ground Test. Warm-up
procedures and ground test are the same as those
outlined in Section II.
Taxiing. Whenever possible, taxiing in
deep snow, light weight dry snow, or slush should be
avoided, particularly in colder FAT 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,
ensure that the bleed air valves are open and that the
condition levers are in HIGH IDLE An outside observer
should visually check wheel rotation to ensure brake
assemblies have been deiced.
(1) If icing conditions are expected, activate
all anti-ice systems before takeoff, allowing sufficient
time for the equipment to become effective.
(2) If the possibility of ice accumulation on
the horizontal stabilizer or elevator exists, takeoff will
not be attempted.
Takeoff. Takeoff procedures for cold
weather operations are the same as for normal takeoff.
Taking off with temperature at or below freezing, 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. Before
flight into icing conditions, the pilot and copilot
WINDSHIELD anti-ice switches should be set to the
(1) After takeoff from a runway covered
with snow or slush, it may be advisable to leave brake
deice ON to dislodge ice accumulated from the spray of