Air Conditioning And Pressurisation Flashcards
Cabin altitude in pressurised flight is
The altitude corresponding to the cabin pressure regardless of aircraft height
Normal Pressurised climb pressure reduction must not exceed
Not exceed 500ft/min
Pressurisation system works
Air pumped into cabin pressure hull
Regulation via outflow valves to dump pressure overboard
Pressure controller sense and maintain required differential pressure between cabin atmosphere
Constant input mass flow and variable output
Cabin altitude vs cabin pressure in climb
Ambient pressure and cabin pressure both decrease but cabin altitude rises more to allow fuselage to pressurise more gradually
Pressure controller sets rate of climb to ensure desired cabin altitude is reached at same time as ac reaches cruise
What component controls max differential in pressurisation system
Cabin pressure controller
How to work out pressurisation in climb (cabin rate of climb)
Work out difference in cabin altitude
Cabin rate of climb required = cabin altitude rate/time
Ditching Valve
Prevent water entering the hull when an emergency landing has taken place on water
Closes the flow valves
Cabin altitude is reached when
Rate of discharge from outflow valve equals inflow air provided by the mass flow controller
Constant pressure maintained
Isobaric Range
The cabin altitude is equal
Cabin decompression - normal decompression
6 to 10 seconds
Rapid decompression
4 to 6 seconds
Explosive decompression
0 to 3 seconds
10,000ft cabin pressurisation
Visual audible warning
At 14,000ft excessive cabin altitude will
Deploy oxygen masks before exceeding 15,000ft
Cabin decompression steps
Mask on
Close outflow valves
Initiate descent
