Avionics Cooling; Instrument Panel Cooling - BOMBARDIER LEARJET 40 Pilot's Manual

Pilot's Manual
• WX (weather) — selects the weather radar main operating
mode.
• GMAP (ground map) — in the ground mapping mode, the
system internal parameters are set to enhance returns from
ground targets.
• FP (flight plan) — selecting this position places the radar in the
flight plan mode.
• TST (test) — when this mode is selected the weather depiction
will be a special colored test pattern to allow verification of sys-
tem operation.
Power is provided to the RTA and cockpit controller from the right
avionics main bus with a 7.5-amp circuit breaker located in the
INSTRUMENT/INDICATIONS group of the copilot's circuit breaker
panel.

AVIONICS COOLING

INSTRUMENT PANEL COOLING

The instrument panel cooling system is located forward of the throttle
quadrant and is provided to draw flight deck ambient air through the
instrument panel and thus prevent overheating of avionics displays
and instruments. The system consists of an avionics cooling fan, an on/
off thermostat switch and an overtemperature thermostat circuit. The
avionics cooling fan is activated when the temperature sensing switch
reaches 90° F (32° C). The fan automatically turns off when the temper-
ature has been reduced below 70° F (21° C). If the temperature reaches
an extreme of 135° F (57° C) the overtemperature circuit is energized
and an annunciation is posted on the CAS. The CAS remains displayed
until the temperature has been reduced to 125° F (51.7° C).
The following CAS illumination is specific to the avionics cooling sys-
tem:
CAS
INSTR PNL TEMP
The instrument panel cooling system is powered from the L MAIN bus
and protected by the INSTR FAN 3-amp circuit breaker located on the
pilot's circuit breaker panel (ENVIRONMENTAL group).
5-78
Color
White The temperature at the instrument panel is
higher than normal.
Description
PM-132A