Cold Weather Operation; Starting - Cessna 172S Nav III Information Manual

SECTION 4 CESSNA
NORMAL PROCEDURES MODEL 172S NAV III
COLD WEATHER OPERATION
Special consideration should be given to the operation of the
airplane fuel system during the winter season or prior to any flight in
cold temperatures. Proper preflight draining of the fuel system is
especially important and will eliminate any free water accumulation.
The use of additives such as isopropyl alcohol or diethylene glycol
monomethyl ether may also be desirable. Refer to Section 8 for
information on the proper use of additives.
Cold weather often causes conditions which require special care
during airplane operations. Even small accumulations of frost,
ice, or snow must be removed, particularly from wing, tail and
all control surfaces to assure satisfactory flight performance
and handling. Also, control surfaces must be free of any internal
accumulations of ice or snow.
If snow or slush covers the takeoff surface, allowance must be made
for takeoff distances which will be increasingly extended as the
snow or slush depth increases. The depth and consistency of this
cover can, in fact, prevent takeoff in many instances.
STARTING
When air temperatures are below 20°F (-6°C), use an external
preheater and an external power source whenever possible to
obtain positive starting and to reduce wear and abuse to the engine
and electrical system. Preheat will thaw the oil trapped in the oil
cooler, which probably will be congealed prior to starting in
extremely cold temperatures.
WARNING
WHEN TURNING THE PROPELLER BY HAND,
TREAT IT AS IF THE MAGNETOS SWITCH IS IN
THE ON POSITION. A LOOSE OR BROKEN
GROUND WIRE ON EITHER MAGNETO COULD
ENERGIZE THE ENGINE.
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