BOMBARDIER BD-100-1A10, Operating Manual

Page: 95 / 544

AIR CONDITIONING/PRESSURIZATION
Sep 13/2004 Flight Crew Operating Manual Volume 2
REV 1 CSP 100-6
02-03-09
AVIONICS AND COCKPIT DISPLAYS VENTILATION
DESCRIPTION
The avionics and cockpit displays cooling system ensures the ventilation of the avionics and displays in order to comply
with aircraft reliability and safety requirements.
The system consists of an underfloor fan and avionics cooling valve, either of which pulls air from the cockpit panel area
behind the displays and from above the avionics racks. During ground operations, the fan is operated in high speed mode.
During flight the fan is operated at low speed unless the temperature in the avionics racks reaches 122
°
F (50
°
C
)
in 60
seconds, then the fan operates at high speed. If the temperature rises above 149
°
F (65
°
C) during a 60 second time period
while the aircraft is above 10 000 ft the fan is turned off and the avionics cooling valve is opened by the IASC. If the fan
or valve fails, an EQPT RACK COOL FAULT (A) CAS message is displayed. If an overheat condition occurs in the avi-
onics rack, an EQPT RACK TEMP HIGH (C) CAS message is displayed.
Control and monitoring is normally operated by IASC 1, in the event of failure in the system, a degraded mode, controlled
by IASC 2 is activated and the avionics fan is turned on. If the fan has failed, then the avionics valve opens.
CF
O
0202002_ 007
DISPLAY
UNITS
CABIN
DOOR
AVIONICS
EXHAUST
FAN
TO AVIONICS VALVE
TO OVERFLOW VALVE
C
F
O
0203002_00
2
AVIONICS
RACK
CHECK
VALVE
OUTFLOW
VALVE
DISPLAYS
COCKPIT
AVIONICS
VALVE
FAN
REV 1