Pressurization Flashcards
AUTO PRESS (DC BUS ) Memorize departure field elevation up to ...
3500 ft
AUTO PRESS panel - ELV SET
Trigger switch to set landing elevation
AUTO PRESS panel - DESCENT RATE
- NORM=
- FAST
- NORM: -400 ft/min
- FAST: -500 ft/min
Fast is used when Vs > -1500 ft/min
AUTO PRESS panel - TEST
Displays alternately 18800 and –8800, FAULT appears on MAN pb.
!!! Test is inhibited in flight !!!
AUTO PRESS panel - DUMP FUNCTION ON (guarded pusbutton)
A fully open signal is sent to the electropneumatic valve and to its slave, the pneumatic valve.
!!! DUMP function is available as long as pressurization is in AUTO mode !!!
Cabin pressure indicators - ALT
The cabin altitude is based on:
29.92 in.hg (1013,2 hPa)
Cabin pressure indicators - DIFF
Maximum and minimum differential pressure values …
+6.35/–0.5
MAN RATE KNOB - NORM
AUTO MODE position.
When used in MAN mode (only the pneumatic valve operates), cabin rate selection +2500/–1500 fpm
CABIN PRESS panel - DITCH
Pb ON - two electrical motors close both outflow valves.
!!! Ditching mode is available in both automatic and manual modes !!!
CABIN PRESS panel - FAULT
digital controller failure. CAP + AIR on CAP
CABIN PRESS panel - MAN
Digital controller out of operation.
no more digits in landing elevation display
By who is the pressurization done and what is the working principle:
Compressed air is delivered by the packs. Pressure is controlled by the amount of cabin air discharged outboard by the outflow valves.
How many outflow valves are there installed …
Two valves:
- An electropneumatic
- A pneumatic
How is the functioning of the valves in automatic mode:
The pneumatic valve is slaved to the electropneumatic one and their opening will be the same
AUTO MODE operation:
The digital controller receives signals (landing elevation, take off elevation, cabin pressure and aircraft static pressure generated by ADC 1 with CAPT altimeter baro setting or, in case of ADC 1 failure, aircraft static pressure generated by ADC 2 with a 1013.2 hPa reference) and operates the outflow valves during all phases of flight.
