Pressurisation Flashcards
Max pressure differential for a jet transport
9 psi
Max cabin alt (normal)
8,000ft
At what height does the cabin alt warning system activate
10,000ft
Cabin o2 automatically drops at
14,000ft
Max cabin alt in an emerg
15,000ft
Pax comfort roc and rod of the cabin
Roc = 500fpm
Rod = 300fpm
Max roc and rod for the cabin
1800fpm
Max negative differential pressure
1/2 psi
Pressurised areas of the a/c
F/d
Fwd and aft cabins
Fwd and aft cargo holds
Unpressurised areas of the a/c
Radome Nose u/c bay Centre section torque box Main u/c bay Tail cone
Discharge/ outflow valves purpose and are controlled by - pressurisation
Controls pressurisation to allow for a varying rate of air being discharged to the atmosphere
Controlled by the pressure controller when in automatic or manual by the flight crew
Safety valve - pressurisation
Outwards pressure relief valve for when the max diff has been exceeded
Valve will open at 0.25 psi above the max diff
Normally occurs when the pressure controller is unserviceable
Inwards relief valve
Fitted to prevent excessive negative differential pressure - open if the pressure outside the a/c exceeds that of inside by 0.5
Dump valve
Allows the crew to dump all cabin pressure - operated manually
Pressure controller
As the cabin altitude changes, the controller automatically sends a signal to the outflow valves - regulate the release of air - maintain the a/c at the preselected levels
What happens when ditching - pressurisation
Slated ditching control will close the outflow valves in the event of l/d on water
Min system instrumentation for pressurisation
Cabin altimeter - reads cabin pressure
Cabin VSI
Cabin diff pressure - diff between the cabin and atmospheric pressure
What are the aural/visual warnings when the cabin alt exceeds 10,000
Horn and a red light on the centralised panel - visual and aural CABIN ALT warning
Or
Warning caption on the EICAS or ECAM
At what height does the AUTO FAIL light on the pressure controller panel illuminate
13,850ft
When is the pressurisation system ground tested and checked
Initial proof testing
When specified in the manual
After actual or suspected malfunction
After repairs and modifications to the hull
Ground testing and system checking of the pressurisation system include testing
Pressure controllers and temp control Max diff control Safety valve check Leak rate check General functioning
Rate/proportional control is maintained during (pressurisation)
Climb and descent
Cabin climbs and descends proportionally
Why do we put a bit of pressure in while taxing
Makes for a smooth transition and stops crap getting in
Set to about 0.1psi - doors can’t open until this has been dumped
