Learjet 60 - Land R Ws Defog Annunciators; Windshield Anti-Ice - Alcohol System

Normal system operation is indicated by illumination of the L and R
WS DEFOG annunciators when the system is activated (windshield
temperature below 85'F (29 ° C]) . When
the windshield is heated above
85'F (29'C), the annunciators will extinguish .
LAND
R WS DEFOG
ANNUNCIATORS
Illumination of a WS DEFOG annunciator, located on the glareshield
annunciator panel, indicates an over-temperature
condition, under-
temperature
condition or loss of AC or DC power . Temperature sensors
are attached to each windshield panel
which provide temperature
to the
windshield heat control unit .
Should the temperature
of ,
windshield
drag below 85'F (29C), the applicable WS DEFOG annun-
ciator will illuminate to alert the crew . Should the temperature of the
windshield
increase above 150'F (66'C), the
applicable WS DEFOG an=
nunciator will illuminate and the affected windshield
will
be cteactivat-
ed . When the windshield cools to the normal operating range, the
system will reactivate and beWS DEFOG anriunciator will extinguish .
Electrical faults detected by the system monitor will cause
the
affected
WS DEFOG annunciator to
illuminate .
WINDSHIELD ANTI-ICE - ALCOHOL SYSTEM
The alcohol anti-ice system is utilized for windshield anti-icing in the
event of a windshield heating
system malfunction . Alcohol anti-icing is
accomplished by directing methyl alcohol over the pilot's windshield
surface through an external outlet in the windshield heat outlet nozzle
assembly . The system consists of a 2 .35 gallon alcohol reservoir, a float
switch, a filter, a relief valve, a three-way control valve, a bleed air shut-
off and
pressure regulator
valve, a
system switch, an
amber ALC LOW
caution
light
and associated aircraft wiring . The pressure relief valve is
installed to prevent system overpressurization by venting system pres-
sure greater than 2 .6 psi above ambient, and bleed system pressure
when
be system
is
off . The system control circuits operate on 28 VDC
supplied
through
the 5-amp ALCOHOL SYSTEM circuit breaker on be
copilot's circuit breaker panel .
644
Learjet6O
Normally, the
left inverter will power the left wind-
shield panel while the right inverter will power the
right windshield panel .
However, either inverter is
capable of
powering both
windshield
panels, Should
,ter switch be in the on position and the oth-
er in the off position, switching will
occur
allowing
the
operative inverter to power
both
windshield
panels .
Ph4423
Change 4