BOMBARDIER BD-100-1A10, Operating Manual

Page: 102 / 544

AIR CONDITIONING/PRESSURIZATION
Volume 2 Flight Crew Operating Manual Sep 13/2004
02-04-06
CSP 100-6
REV 1
CONTROLS AND INDICATIONS (Cont)
LANDING SEQUENCES AT FIELD ELEVATION GREATER THAN 7850 FT
This sequence does not require additional crew action, if the actual landing field elevation was selected prior to takeoff.
The scheduled cabin pressure altitude is normally limited to 7850 ft during flight and then automatically reset to the landing
field pressure altitude.
The CABIN ALTITUDE (C) CAS message is normally set for 8500 ft and the CABIN ALTITUDE (W) CAS message and
aural “CABIN ALTITUDE” voice warning is set for 9400 ft. When the aircraft descends below 41 000 ft, the caution and
warning thresholds start to increase as a function of the aircraft altitude and aircraft rate of descent.
The CABIN ALT WARN HIGH (A) CAS message is displayed, informing the crew that the warning and caution limits
have been reset to higher than normal values.
The CABIN ALTITUDE (C) message increases up to 650 ft above landing field pressure altitude and the
CABIN ALTITUDE (W) message increases up to 1550 ft above the landing field pressure altitude. Both thresholds are lim-
ited to 14 300 ft pressure altitude.
LEVELING OFF DURING DESCENT
If a leveling off occurs above 41 000 ft during descent:
- The cabin altitude remains at 7850 ft
- The CABIN ALTITUDE caution and warning remain at 8500 ft and 9400 ft respectively
If leveling off between 41 000 and 25 000:
- The cabin altitude as well as caution and warning thresholds will level also as a function of aircraft altitude
- If the leveling off lasts for more than 3 minutes, the cabin altitude will descend at a rate of -300 sea level fpm back-
wards towards 7850 ft. The caution and warning thresholds will also descend at a rate of -300 fpm until aircraft
descent is initiated
If leveling off occurs at or below 25 000 ft during descent:
- The cabin will reach and remain at targeted landing field pressure altitude minus 300 ft
- The CABIN ALTITUDE caution and warning thresholds will reach and remain at landing field pressure altitude
+650 ft and + 1550 ft respectively with both limited to 14 300 ft
If a short climb followed by a level off is performed below 25 000 ft, cabin altitude will descend at a rate of -300 sea level
fpm back towards 7850 ft. A subsequent aircraft descent will automatically initiate the return to the landing field pressure
altitude and decrease the caution and warning thresholds.
TAKEOFF AND RETURN TO BASE SEQUENCE AT FIELD ELEVATION GREATER THAN 7850 FT
Similar to the takeoff at lower field elevations, as the aircraft leaves the ground, the takeoff sequence is initiated. The system
will maintain the pre pressurization cabin altitude of 300 ft below takeoff pressure altitude until the aircraft reaches 6000
ft AGL or 10 minutes has elapsed. If a return to base is initiated the aircraft will land slightly pressurized at the pre pres-
surization value to avoid cabin bumps and the landing field elevation does not have to be reset. During this sequence, the
caution and warning thresholds will be maintained at the takeoff pressure altitude.
CLIMB MODE WITH SELECTED LANDING FIELD ELEVATION GREATER THAN 7850 FT
When the aircraft is in climb following a takeoff from an airfield above 7850 ft, the cabin altitude will decrease at a rate of
-500 sea level fpm towards the maximum normal limit of 7850 ft. The caution and warning thresholds decrease as a func-
tion of the aircraft altitude and the aircraft rate of climb, but at a minimum rate of -500 sea level fpm in order for the caution
threshold to reach 8500 ft and the warning threshold to reach 9400 ft before the aircraft reaches 41 000 ft.
CRUISE MODE WITH SELECTED LANDING FIELD ELEVATION GREATER THAN 7850 FT
When the aircraft is in cruise following a takeoff and climb from an airfield above 7850 ft, the cabin altitude will continue
to decrease at a rate of -300 sea level fpm until the maximum normal cabin altitude limit for 7850 is reached.
The warning and caution thresholds will continue to decrease at a rate of -300 fpm until the caution threshold of 8500 ft
and the warning threshold reaches 9400 ft.