Learjet 36A - Anti-Ice Systems

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ANTI-ICE SYSTEMS
Anti-ice systems should be turned on prior to operation in icing conditions.
Icing conditions exists when the outside air temperature
is 10°C to -40°C
and visible moisture in any form is present (such as clouds, rain, snow, sleet,
ice crystals, or fog with
visibility of 1 mile or less.)
If icing conditions are encountered and the anti-ice systems have not been
energized, turn them on prior to significant ice accumulation. Observe rec-
ommendations
for normal use of all anti-ice systems.
Even
smaU accumulations of ice on the wing leading
edge can cause aerodynamic stall prior
to activation of
the stick shaker
and/or pusher. These ice accumulations
can also cause angle-of-attack indicator information to
be unreliable.
Minimize the duration of icing encounters as much as practical. Minimize
holding in icing conditions with
flaps extended. This includes requesting an
altitude above or below icing conditions, if practical.
Intermittently operating with the autopilot off
will allow more readily detect-
able changes
in flight control feel.
If flight has been conducted in icing conditions, remove any accumulated ice
prior to next
flight.
In the event of significant ice accumulation or failure of any portion of the
anti-ice system, refer to INADVERTENT
ICING ENCOUNTER and/or
appropriate Anti-Ice System Failure procedures in Section IV.
When using anti-ice systems at high altitude, the cabin altitude may exceed
8000 feet unless engine speed is increased to compensate for the additional
bleed air extraction.
Aircraft anti-icing
is accomplished through the use of electrically heated
anti-ice systems, engine bleed-air heated anti-ice systems, and alcohol anti-
ice systems. Electrically heated systems include static ports, pitot tubes, en-
gine inlet air-temperature and pressure sensor, and stall warning vanes.
En-
gine bleed air is utilized to heat the wing leading edge, horizontal stabilizer
leading edge, windshield and engine anti-icing. An alcohol anti-ice system
is installed for radome anti-ice and as a back-up for windshield bleed air anti-
ice system.
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2-66
In icing conditions above approximately 12,000 feet,
ice buildup may occur at the junction of the wings and
tip tanks. Satisfactory handling qualities have been dem-
onstrated with this ice accumulation. Below approxi-
mately
12,000 feet, using normal descent procedures,
all wing leading edge ice will be removed.
FAA APPROVED 4-30-76
REISSUED 2-25-81, CHANGE 12