Fuselage Pressurization Cycles

[halls]

I need to understand the pressurization cycle for a typical transport category aircraft as it climbs and descends through different altitudes so I can determine the pressure differential across the skin at any given altitude. Can anyone help me or point me in the right direction, preferably accessible through the Web?

Thanks,

Steve

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Steve Hall (halls@celeris.ca)

[wxwatcher]

I really don't know the formulas or math involved, but, if I recall correctly, most commercial passenger aircraft are presurized to a constant 8000 msl during flight, regardless of the actual cruising altitude. Therefore, the pressure differential will vary according to the actual altitude of the aircraft.

Jerry

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Comments and opinions are my own and do not reflect those of my employer.

[djschaut]

It would seem to me that a cabin altitude of 8000' at an aircraft altitude of 8000' would create a differential of 1/1. A cabin altitude of 8000' at an aircraft altitude of 16,000' would give a pressure differential of 2/1. A cabin altitude of 8000' at an aircraft altitude of 32,000' would give a pressure differential of 4/1. This is because the measure of cabin altitude and the measure of outside altitude are done using altimeters calibrated at the same barometric pressure, with sea level at 0 ft. with the altimeter set at 29.92" Maybe it's not that simple.

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DJSchaut