Protection Systems; Normal Differential Control; Overpressure Limiter; Altitude Limiter - BOMBARDIER Challenger 601-3A CL-600-2B16 Pilot Training Manual

INDICATIONS
When electrical power is initially provided, or
the mode selector switch is moved to auto
from manual, the computerized controller per-
forms a self-test which, if successful, illumi-
nates the amber FAULT and AUTO FAULT
lights for two seconds only.
A dual-scale, three-needle indicator (Figure
12-2) on the copilot's side panel provides si-
multaneous indication of (1) cabin altitude in
thousands of feet, (2) cabin atmosphere-dif-
ferential pressure in psid, and, when applica-
ble, (3) cabin rate of change up or down in feet
per minute times 1,000. The cabin altitude
needle is labeled "ALT," and the cabin differ-
ential pressure needle is labeled "PSI." Both
indicate on the same scale. The cabin rate-of-
change needle indicates on the left scale and
the needle is not labeled.
An amber light labeled "CABIN PRESS LOW"
on the pressurization control panel (Figure
12-1 and Annunciator Panel Section) is oper-
ated from an aneroid switch behind the panel.
The light will illuminate if the cabin altitude
exceeds approximately 10,400 feet. In addi-
tion, the NO SMOKING, SEAT BELTS, and
ENVironmental CONTrol annunciators will il-
luminate, and the MASTER CAUTION lights
(Annunciator Panel Section) will flash.
RATE DISPLAYS
CABIN RATE OF CLIMB
0
ALT DISPLAY
CABIN ALTITUDE
Figure 12-2. Cabin Altimeter—
Differential—Rate Indicator
12-4 CL 601-3A
PSI DISPLAYS CABIN
DIFFERENTIAL PRESSURE
0
1
2
2
3
1
4
UP 5
RATE X 1000
6
DN
7
CABIN
1
8
9
2
10
20
40
ZERO RATE
ADJUSTMENT
FOR TRAINING PURPOSES ONLY FOR TRAINING PURPOSES ONLY
FlightSafety Canada
CL-600-2B16 PILOT TRAINING MANUAL

PROTECTION SYSTEMS

The protection systems incorporated in the
pressurization system are:

• Normal differential control

• Overpressure limiter (maximum differ-
ential)

• Altitude limiter

• Negative pressure relief
NORMAL DIFFERENTIAL
CONTROL
The normal differential control is an auto-
matic function of the pressurization controller
when operating in the AUTO mode. Normal
differential pressure for the controller is lim-
ited to 8.8 psid.

OVERPRESSURE LIMITER

Each outflow valve includes an overpressure
limiter that constantly senses the difference be-
tween cabin pressure and atmospheric pressure.
If this value reaches approximately 9.1 psid, ei-
ther, or both, valve(s) will respond and increase
the metering rate to limit the differential.
ALTITUDE LIMITER
Each outflow valve includes an altitude lim-
iter to prevent cabin altitude from exceeding
a preset value. Cabin pressure is admitted to
a sealed bellows chamber, compressing the
bellows and keeping a valve closed. If cabin
altitude reaches approximately 13,000 ±500
feet, the bellows will expand (because of the
decreasing cabin pressure) and open the limit
valve. The outflow valve will close and limit
the cabin altitude to approximately 13,000
±500 feet.
L t é e
L t d.