Learjet 60 - PITOT HEAT Switches; PITOT HT Light; Pitot-Static and Stall Warning Anti-Ice

Learjet 60

Pilot's Manual
PITOT-STATIC AND STALL WARNING ANTI-ICE
Anti-ice protection for the pitot-static probes, total temperature probe,
stall warning vanes, and the pressurization static port is accomplished
by energizing integral electrical heating elements in each component .
The independent pitot-static probe, total temperature probe, and stall
warning vane anti-ice systems consist of control switches, probe heat-
ers, vane heaters, and pitot heat monitors . Both left, right and standby
systems utilize the same PITOT HT light . The pressurization static port
heater is
part
of the right system . The pitot-static probe
heating
ele-
ments receive 28 VDC through their respective 15-amp L PITOTHEAT,
R PITOT STALL-TAT HEAT, and STANDBY PITOT HEAT circuit
breakers on the pilot's and copilot's circuit breaker panels . The total
temperature probe
heating
element receives 28
VDC through the
15-amp TAT PROBE HEAT circuit breaker on the copilot's circuit break-
er panel . Total temperature probe heat is only enabled when the squat
switch
is
in
the air mode . The pressurization static port heating element
receives 28 VDC
through
the 15-amp R PITOT STALL-TAT HEAT
circuit breaker on the copilot's circuit breaker panel . The stall warning
vane heating elements receive 28 VDC through the respective 15-amp
L and R STALL VANE HEAT circuit breakers on the pilot's and
copilot's
circuit breaker panels .
An optional Triple Pitot Heat Indication System may be installed . The
system does not change the anti-ice protection for the pitot-static
probes, stall warning vane, or total temperature probe . It does add
specific warning annunciators in the event of failure of either left, right,
or
standby
pitot-static heat system
. The
annunciators are installed on
the center instrument panel, below the PITOT HEAT placard .
PITOT
HEATSWITCHES
The pitot-static heat systems are controlled through the PITOT HEAT
switches in the ANTI-ICE group on the center switch panel . Each
switch has two positions : On (L or R) and OFF . When the L and R
PITOT HEAT
switches are set to On
(L
and
R), power is
supplied to
each pitot-static probe heater, each stall warning vane heater, the total
temperature probe heater (aircraft in flight), and the pressurization
static port heater . The standby pitot-static probe, pressurization static
port, and
the total temperature
probe
heat are
activated through
the
R
PITOT HEAT switch .
PITOT HT
LIGHT
A pitot heat monitor system is installed to alert the pilot if insufficient
current is being applied to any of the pitot-static probe heating ele-
ments (left, right and standby) . Each monitor is basically a relay which
PM-123

6-17
Change 4