Re: Passenger cabin pressurization

Date:         17 Sep 97 02:49:16 
From: (Larry Stone)
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In article <airliners.1997.2233@ohare.Chicago.COM>, wrote:

>Kind of a related question. I almost remember hearing, from some
>flight crew friend of mine, that most airlines actually decrease
>pressure prior to take-off. This way, they have to accelerate less
>mass during the takeoff process. Is this ever true? I've felt pressure
>changes in planes on the tarmac prior to takeoff (ear pop), but
>this may be caused by Gerry's pressure bump.

Aircraft pressurization systems hold a high pressure inside the plane than
outside. Since the actual control mechanism is an outflow valve (allowing
air out of the cabin to outside), there's no way to make the plane's
pressure inside less than the outside.

-- Larry Stone ---
   Belmont, CA, USA
   My opinions, not United's.