Hot Weather Operation; Engine Heat Soaking - Continental Motors O-470-B Operator's Manual

HOT WEATHER OPERATION
(Ambient Temperature in Excess of 90°F.)
CA
UTION ... Whe,n operating in hot weather areas, he alert for
higher than normal levels of dust, dirt or sand in the air. Inspect air
filters
frequent~l'
and be prepared to clean
or
replace them (f
necessary. Weather conditions can
I(fi
damaging levels
(~fdllst
and
sand high above the ground. In the event the aircra/i .\"hould he
.f70wn through such conditions, an oil change is recommended as
soon as is practical. Do not intentiona/fl' operate the engines in dust
and/or sand storms. The use of dust COl'ers on the cowling
will
afford additional protection for a parked aircraft.
In-flight operation during hot weather usually presents no problem
since ambient temperatures at flight altitudes are seldom high
enough to overcome the cooling system used in modern aircraft
design. There are, however, three areas of hot weather operation
which will require special attention on the part of the operator.
These are: Starting a hot engine, Ground operation under high
ambient temperature conditions and Takeoff and initial c1imbout.
Engine Heat Soaking
After an engine is shutdown, the temperature of its various com-
ponents will begin to stabilize; that is, the hotter parts such as
cylinders and oil will cool, while other parts will begin to heat up due
to lack of air flow, heat conduction, and heat radiation from those
parts ofthe engine which are cooling. At some time period following
engine shutdown, the entire unit will stabilize near the ambient
temperature. This time period will be determined by temperature
and wind conditions and may be as much as several hours. This heat
soaking is generally at the worst from 30 minutes to one hour
following shutdown. During this time, the fuel system will heat up
causing the fuel in the pump and lines to "boil" or vaporize. During
subsequent starting attempts, the fuel pump will initially be pump-
ing some combination of fuel and fuel vapor. Until the entire fuel
system becomes filled with liquid fuel, difficult starting and unstable
engine operation may be experienced.
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