If fuel tanks are completely filled during hot
overflow, creating a fire hazard.
j. Before Leaving Aircraft. Use normal
procedures in Section II. Take extreme care to
prevent sand or dust from entering the fuel and oil
system during servicing. During hot weather, release
the brakes immediately after installing wheel chocks to
prevent brake disc warpage.
Due to the comparatively light wing
loading, control in severe turbulence and
thunderstorms is critical. Since turbulence
imposes heavy loads on the aircraft
structure, make all necessary changes in
aircraft attitude with the least amount of
control pressures to avoid excessive loads
on the aircraft structure.
Thunderstorms and areas of severe turbulence
should be avoided. If such areas are to be penetrated,
it will be necessary to counter rapid changes in attitude
and accept major indicated altitude variations.
Penetration should be at an altitude which provides
adequate maneuvering margins as a loss or gain of
several thousand feet of altitude may be expected.
The recommended penetration speed in severe
turbulence is 170 KIAS. Pitch attitude and constant
power settings are vital to proper flight technique.
Establish recommended penetration speed and proper
attitude prior to entering turbulent air to minimize most
difficulties. False indications by the pressure
instruments due to barometric pressure variations
within the storm make the instruments unreliable.
Maintaining a pre-established attitude will result in a
fairly constant airspeed. Turn cockpit and cabin lights
on to minimize the blinding effects of lightning. Do not
use autopilot altitude hold. Maintain constant power
settings and pitch attitude regardless of airspeed or
altitude indications. Concentrate on maintaining a level
attitude by reference to the flight director/attitude
indicator. Maintain original heading. Make no turns
unless absolutely necessary.
8A-59. ICE AND RAIN (TYPICAL).
While in icing conditions, if there is an
unexplained 30% increase of torque
needed to maintain airspeed in level flight,
a cumulative total of 2 or more inches of
unexplained decrease of 15 KIAS, or an
unexplained deviation between pilot's and
copilot's airspeed indicators, the icing
environment should be exited as soon as
practicable. Ice accumulation on the pitot
tube assemblies could cause a complete
loss of airspeed indication.
The following conditions indicate a possible
accumulation of ice on the pilot tube assemblies and
unprotected aircraft surfaces. If any of the following
conditions are observed, the icing environment should
be exited as soon as practicable:
1. Total ice accumulation of 2 inches or more
on the wing surfaces. Determination of ice
summing the estimated ice thickness on
the wing prior to each pneumatic boot
deice cycle (e.g., four cycles of minimum
recommended 1/2 inch accumulation).
2. A 30% increase in torque per engine
required to maintain desired airspeed in
level flight (not to exceed 85% torque)
when operating at recommended holding/
3. A decrease in indicated airspeed of
15 knots after entering the icing condition
(not slower than 1.4 times the power off
stall speed) if maintaining original power
setting in level flight. This can be
condition entry speed to the indicated
speed after a surface deice cycle is
4. Any variations from normal indicated
airspeed between the pilot's and copilot's
a. Typical Icing. Icing occurs because of
supercooled water vapor such as fog, clouds, or rain.
The most severe icing occurs on aircraft surfaces in
visible moisture or precipitation with a true outside air
temperature between 5 °C and +1 °C. However,
under some circumstances, dangerous icing conditions
may be encountered with temperatures below 10 °C.