AIR_CABIN PRESSURIZATION PANEL Flashcards
1
Q
AUTO FAIL Light
What could cause the AUTO FAIL light to illuminate? (1sp)
A
[1sp:
- cabin alt - rate of change too high (>2000 fpm)
- cabin alt - too high (>15,800’)
- cabin alt - differential press too high (>8.75 psi)
- CPC failure
- Outflow valve control fault
- loss of power (DC 1 or DC 2) ]
Illuminated (amber):
- means automatic pressurization system failure detected (ie one or more channels are inop)
- MC + AIR COND light illuminate
- moving the selector to ALTN will extinguish AUTO FAIL light if the other CPC is working correctly
-
Reasons for [AUTO FAIL]
- cabin alt - rate of change too high (>2000 fpm)
- cabin alt - too high (>15,800’)
- cabin alt - differential press too high (>8.75 psi)
- CPC failure
- Outflow valve control fault
- loss of power (DC 1 or DC 2)
-
SINGLE CONTROLLER FAILURE: (CPC Failure)
- [AUTO FAIL + ALTN} light illuminated
-
DUAL CONTROLLER FAILURE:
- [AUTO FAIL] light illuminated alone
- FLT ALT and LAND ALT show 5 dashes (meaning the auto system is not working)
- must manually go to the MAN mode
2
Q
OFF SCHED DESCENT Light
When would this light come on? (1sp)
A
[1sp: you start descending before you reached your planned cruise altitude]
Illuminated (amber):
- comes on if airplane descends prior to reaching w/in .25 psi (about 1,000’) of FLT ALT selected when in the AUTO or ALTN press modes
Notes.
- controller programs airplane to land back at departure airport if this happens automatically
- light will go out when:
- you get to FLT ALT
- airplane begins to climb again
- FLT ALT is reset to current altitude (lose auto return feature)
- FLT ALT RESET is pressed during climb (lose auto return)
- MAN mode selected
- airplane lands
- if you divert:
- reset FLT ALT to current alt
- set the LAND ALT to divert field
3
Q
ALTN Light
What does this light mean? (1sp)
A
[1sp: the pressurization controller is operating in the alternate mode]
Illuminated (green):
- press system operating in alternate automatic mode
- if both ALTN and AUTO FAIL lts are on = single controller CPC failure
4
Q
MANUAL Light
A
Illuminated (green):
- pressurization system operating in the MANUAL mode
- you now have to control the position of the outflow valve
- at traffic pattern altitude - position outflow valve FULL OPEN
5
Q
FLIGHT ALT Indicator
A
Indicator.
- indicates selected cruise altitude
- set before takeoff
- ‘88888’ or ‘all dashes’ - if you see this it is caused by a DC power interruption. if cabin alt and rate are normal, automatic control of cabin pressure is not affected by failure
Selector.
- rotate to set planned cruising altitude in 500 foot increments
6
Q
LAND ALT Indicator
A
Indicator.
- indicates altitude of intended landing field
- set before takeoff
- ‘88888’ or ‘all dashes’ - if you see this it is caused by a DC power interruption. if cabin alt and rate are normal, automatic control of cabin pressure is not affected by failure
Selector.
- rotate to set planned cruising altitude in 50 foot increments
7
Q
OUTFLOW VALVE POSITION Indicator
A
- indicates position of the outflow valve
- operates in ALL MODES
8
Q
OUTFLOW VALVE Switch
A
- spring-loaded to center
- powered from the BATTERY BUS (DC)
CLOSE:
- closes outflow valve ELECTRICALLY when in MAN mode
OPEN:
- opens outflow valve ELECTRICALLY when in MAN mode
- full range can take 20 seconds
9
Q
PRESS MODE Selector
A
AUTO:
- pressurization controlled automatically
- the AUTO system has 2 identical controllers each with its OWN DC MOTOR
- the active changes every flight OR with [AUTO FAIL] light
ALTN:
- green [ALTN] light illuminates
- if [AUTO FAIL] is illuminated - this position should turn it off
MAN:
- press system controlled manually by outflow valve switch
- BOTH AUTO CONTROLLERS BYPASSED (both CPC’s)
- has its OWN DC Motor - TRIPLE REDUNDANT
- 24v DC Battery Bus power source
10
Q
CABIN/FLT ALT Placard
A
- used to determine setting for cabin altitude when in manual mode
