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COLD WEATHER OPERATION
Predeparture Check
This check will determine the need for deicing. This check is usually
accomplished by the flight crew during the normal walk-around inspection
completed at the gate. Qualified ground personnel may also determine the need
for aircraft deicing without the flight crew present.
The Predeparture check is a check of critical aircraft surfaces to ensure that they
are free of any adhering ice, snow, slush, or frost. Critical aircraft surfaces
include the following:
· Wings – Takeoff with light coatings of frost, up to 1/8 inch (3mm) in
thickness on lower wing surfaces due to cold fuel is permissible. However,
all leading edge devices, all control surfaces, and all upper wing surfaces
must be free of snow, ice, slush, and frost.
· Fuselage – Thin hoarfrost is acceptable on the upper surface of the fuselage
provided all vents and ports are clear. Thin hoarfrost is a uniform white
deposit of fine crystalline texture, which is thin enough to distinguish
surface features underneath, such as paint lines, markings or lettering.
· Tail
· Control Surfaces
· Engine Inlets
· Landing Gear and Gear Doors, Wheels and Brakes
· Air Conditioning Inlets/Exits and Outflow Valves
· Air data Sensors, Stall Vanes, Pitot Tubes and Static Ports
If these aircraft surfaces are not free of any adhering ice, snow, slush or frost,
the aircraft must be deiced prior to departure.
In many cases, it may be necessary to start the engines and/or taxi to another
location prior to deicing the aircraft. In situations such as this, it is permissible
to start the engines and proceed to the deicing area with an accumulation of
snow and/or ice on the aircraft. However, in no case will an aircraft taxi for
takeoff without first ascertaining that the critical aircraft surfaces are free of any
adhering ice snow, slush, or frost.