Learjet 20 Series Pilot Training Manual page 178

Engine bleed air is used to heat the windshields,
wing leading edges, and the engine front frame.
An alcohol system is installed for radome anti-
icing and as a backup to the pilot's windshield
bleed-air anti-icing.
NOTE
All anti-ice systems except engine
front frame heat require electrical
power for operation.
All anti-icing equipment must be turned on
before icing conditions are encountered. To
delay until ice buildup is visually detected on
aircraft surfaces constitutes an unacceptable
hazard to safety of flight.
FRONT FRAME
WING LEADING EDGE
ANTI-ICE (BLEED AIR)
RADOME ANTI-ICE
(ALCOHOL)
10-2
LEARJET 20 SERIES PILOT TRAINING MANUAL
HORIZONTAL STABILIZER
LEADING-EDGE ANTI-ICE
ANTI-ICING
(BLEED AIR)
WINDSHIELD HEAT
(BLEED AIR AND ALCOHOL)
Figure 10-1. Ice and Rain Protected Areas
FOR TRAINING PURPOSES ONLY
Icing conditions exist when visible moisture
is present and the indicated ram-air tempera-
ture (RAT) is +10º C or below. Takeoff into
icing conditions is permitted with all bleed-
air anti-icing systems on. The RAT gage should
be checked frequently when flying in or en-
tering areas of visible moisture.
During descents, the cabin altitude may in-
crease unless sufficient engine rpm is main-
t a i n e d t o c o m p e n s a t e f o r t h e a d d i t i o n a l
bleed-air use. To ensure adequate bleed air
for anti-ice protection and cabin pressuriza-
tion, maintain at least 80% engine rpm.
Figure 10-1 illustrates the ice-protected areas.
(ELECTRIC)
FlightSafety
international
NACELLE LIP ANTI-ICE
(ELECTRIC)