conversation went like this:
Student: "There's ice developing on the windshield."
Instructor: "What are you going to do about it?"
Student: "I don't know."
Any ice that develops on an aircraft indicates immediate action is
How ice forms on an aircraft and what happens is required knowledge for
any IFR pilot. The potential hazards include:
air intakes, static ports, carb air filters
changes, especially the disruption of the laminar flow during rime ice
drag resulting in changes in stalling speed
& balance concerns
reduction in lift.
changes in aircraft performance can occur in less than 10 minutes in
conditions. Types of ice include:
Ice: a smooth, glassy/clear ice formed by slowly freezing water of
supercooled water droplets.
a frosty/milky color ice formed by quick freezing of small supercooled
Ice: a combination of both types, brittle, hard, rough surface.
are reported as defined in the AIM:
Ice becomes perceptible. Rate of accumulation is slightly greater
than sublimation. Deicing/ anti-icing equipment is not utilized
encountered for an extended period of time (>1hr).
The rate of accumulation may create a problem if flight is prolonged in
this environment (>1hr). Occasional use of deicing/ anti-icing
removes or prevents accumulation. It does not present a problem
the deicing/ anti-icing equipment is used.
The rate of accumulation is such that even short encounters become
hazardous and use of deicing/ anti icing equipment or flight diversion
The rate of accumulation is such that deicing/ anti icing equipment
to reduce or control the hazard. Immediate flight diversion is
you expect icing conditions? Anytime you fly in visible moisture
(clouds & rain) between +2C and -10C.
for reducing your risks:
Weather Briefing Tips
of FZRA (freezing rain) and FZDZ (freezing drizzle) are very likely to
produce icing conditions.
sigmets imply severe icing potential.
of 50% relative humidity usually implies icing conditions.
to the center of a low pressure system, moisture moves upwards
This results in icing conditions at higher altitudes.
amended TAFs which indicated better information about icing conditions.
pireps for the route of flight but remember that pireps are a snapshot
at a given moment.
Never fly with frost on your aircraft. Using water to remove
creates clear ice. Use the sun to remove it and be sure the
is dry prior to takeoff.
Use early warning devices on your aircraft: corners of
through windshield thermometers, and wing strut steps are all early
devices for icing conditions.
Any time you experience visible moisture (fog, clouds, rain), use pitot
Stay clear of clouds if possible. Clouds are visible moisture and
are likely to provide you an icing experience to remember, particularly
at the tops. If you are flying through a cloud which is causing
buildup, the bottom of the cloud is less likely to give you more ice
the top. You might be able to descend 1000 feet to clear the
or stop the icing.
If you are experiencing ice, leave the area of precipitation, or leave
that altitude. Use the rule of 4000: it will give you an
degree shift in temperature which will likely end ice accretion.
If you are leaving an area of icing by climbing or descending, use
control movements. Climb and descend at moderate angles of
Induction icing can be just as serious a problem. Use carb heat
icing conditions exist. If using carb heat and alternate air,
the mixture to improve engine performance and increase engine operating
If you are experiencing icing conditions, notify and obtain priority
Give pireps enroute. Example: Cessna 123A over ABC VOR,
at four thousand a Cessna 172. We are experiencing trace ice,
air temperature is 2C.
The standard rate 180 degree turn back out of icing conditions may not
produce the result you're looking for so always have a way out.
During landing, use a stabilized approach with minimal use of flaps and
avoid large power changes.
write to me with your comments and tips for avoiding aircraft icing.
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