cabin pressure

[monkeyboy726]

does anybody know the average cabin atmospheric pressure on the majority of airliners? is it anywhere near the pressure around sea level? thanx

[Eskimo]

I think it's to do with the cruising height.

Eg. FL350 (35,000), the pressure is about 8000 ft.

I think.  ;)

[Craig.]

8000 feet once at cruise altitude regardless from what i have read

[Nexus]

These are general figures

FL220-FL260 = Cabin altitude of 4000
FL260-FL320 = Cabin altitude of 6000
FL320-FL410 = Cabin altitude of 8000

The pressurization systems on modern airliners are very automated so the only thing the system needs to know is the CRZ altitude/ landing field elevation. When at crz level it regulates the psid (psi differential between cabin and ambient psi) after a set schedule which can look like this

SEA LEVEL to 18.500ft= Landing field elevation
18.500-28.000ft = 7.45 psid
28.000ft- 37.000ft = 7.80 psid
37.000ft and above = 8.35 psid