Pressurisation Flashcards
Four functions
Ground: fully open outflow
T/o: increase cabin pressure
In flight: adjust cabin altitude and rate of change
Depressurisation: gradually releases over pressure
Auto operation
Follows schedules from FMGS
If no FMGS, manual set of landing elevation required
Manual
Outflow controlled via control panel
CPC (Cabin pressure controllers)
Receive data from: ADIRS, FMGC, EIU, LGCIU
When auto, one CPC active
Communicate via cross channel
Outflow valve
Actuator has two auto, one manual motor
Operating controller signals position of valve to ECAM
With ram air on, dap below 1, valve goes to 50% on auto, nothing on manual
Safety valves
Prevent cabin pressure too high or low, 8.6 psi above, 1 psi below
Rear of pressure bulkhead
RPCU (Residual pressure control unit)
Auto depressurises aircraft in case of abnormal residual P on ground
Auto opens outflow valve:
Not fully open
CPC failed or man mode
On ground and, engine shutdown or ADIRS indicates below 100 kts
Auto control
Controller switch when: 70s after landing, one fails
Limits cabin P to 8000 ft, supports high alt airfield ops up to 14100 ft
Normally uses: LDG ELEV, QNH FMGC, Pressure alt from ADIRS
Auto control modes
Ground: before t/o, 55s after land fully open, after land releases at 500 ft/min
T/o: pre-pressurises to at 400 ft/min to 0.1 psi
Climb: cabin alt varies according to pre-programmed law
Cruise: limited to max of 8000 ft
Descent: maintains descent so that cabin P is 0.1 psi just before landing, max 750 ft/min
Abort: prevents cabin alt climbing if aborted
Manual control
Release mode select pb
Push MAN V/S CTL switch to control cabin pressure
Outflow valve does not open auto on touchdown
Ditching closes
Outflow valve, emergency ram air inlet, avionics ventilation inlet, pack flow control valves, FWD cargo outlet isolation valve
