General; Failure Detection; Test Function; Pneumatically Operated Systems - BOMBARDIER Challenger 601-3A CL-600-2B16 Pilot Training Manual

When ice is detected, the crew must activate
the wing and cowl anti-icing systems. This
causes the white ICE lights on the right side
of the panel to illuminate and the red (Canadian
amber) ICE lights to extinguish.
When ice is initially detected, the microcom-
puter activates the ice signal for 60 seconds.
It then activates heaters in the probe and strut
for 5 seconds. This deices the probe, allowing
it to return to its natural frequency of 40 kHz.
If ice is detected again, the ice signal is reac-
tivated for an additional 60-second period and
the detector heaters operate for another 5 sec-
onds. This cycle is repeated continuously until
the airplane departs icing conditions.
When ice is no longer being detected, the
white ICE lights extinguish, indicating to the
crew that the wing and engine anti-icing sys-
tems may be selected off.

FAILURE DETECTION

Failure detection circuitry illuminates an
amber FAIL light on the ice detector panel
and causes appropriate master caution reac-
tions if the following failures occur:
• If the program cycle stops. The execu-
tion pulse monitor performs a built-in
test function that detects when the pro-
gram has stopped.
• An internal failure of the microcom-
puter, its function, or the heaters. This
type of fault would not necessarily cause
the program to stop but may cause a
change in the program.

TEST FUNCTION

Depressing the FAIL switchlight on the ice de-
tector panel initiates a test of the system. This
test determines whether or not the internal
circuitry, the heaters, and the ice warning and
failure detection signals are serviceable. A
successful test is indicated by flashing of the
red (Canadian amber) ICE lights.
10-4 CL 601-3A/R
CL-600-2B16 PILOT TRAINING MANUAL
ANTI-ICING SYSTEMS
PNEUMATICALLY OPERATED
SYSTEMS

General

Hot air for the operation of the cowl and wing
anti-icing systems is supplied by the 14th-stage
bleed-air system of each engine's compressor.
The 14th-stage shutoff valves are spring loaded
open and are energized closed. Bleed-air is re-
quired to close these electropneumatic valves.
After engine start, the 14th-stage bleed shut-
off valves are selected open and are normally
left in that position until engine shutdown.
Cowl Anti-icing
An electrically controlled, pneumatically op-
erated, normally closed, pressure-regulating
and shutoff valve controls the flow of bleed air
to the forward cowl of each engine (Figure 10-
4). The regulating air pressure is delivered via
an ejector to piccolo tubes, which spray the hot
air against the cowl leading edge and into the
plenum. Temperature is regulated by recircu-
lating the air (through the ejector) within the
plenum before being discharged overboard.
The fail-safe valves are energized to the closed
position and deenergized to the open posi-
tion. In case of electrical power failure, with
bleed-air pressure available, the valves will au-
tomatically go to the open position and pro-
vide a continuous flow of regulated anti-icing
air until electrical power is restored.
Pressure switches are installed downstream
of the valves. The switches activate FAIL in-
dicators on the anti-icing panel when the open
position has been selected and air pressure in
the duct is insufficient to provide adequate
anti-icing.
The system is further protected by a pressure-
relief valve which provides overpressure
dumping from the cowl duct should a cowl
anti-icing valve fail in the open position.
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