Re: Passenger cabin pressurization

Date:         16 Sep 97 02:37:12 
From:         John Weiss <John.R.Weiss@Boeing.*NOSPAM*.com>
Organization: Boeing Commercial Airplane Group
References:   1 2
Followups:    1
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Gerard Foley wrote:
> jf mezei ("[non-spam]jfmezei" wrote:
> : I have seen mentioned often that modern airliners maintain a cabin
> : pressure of 8000feet when flying at cruise altitude of 30-40k feet.
> : Is this an urban myth or actual precise figure that applies to all
> : airliners ?
>    I used to carry a pocket altimeter with me on airplanes (lately I
> forget to take it).  Different aircraft behaved in different ways,
> but I never had one that got down as low as 8000 feet equivalent
> pressure.

I'm not sure about "all" airliners, but the 777 was designed for an 8000
foot cabin at max cruise altitude.

Assuming the crew has control over the pressurization, at lower
altitudes they could either reduce the pressure differential to maintain
that cabin altitude, or keep the pressure differential constant and
allow a lower cabin altitude.  I don't know what the "normal" schedule
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