Re: Passenger cabin pressurization

Date:         06 Oct 97 02:14:23 
From:         Chris Dahler <>
References:   1 2 3 4
Next article
View raw article
  or MIME structure

Larry Stone wrote:

> 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.

Aircraft designs do allow for the possibility, however.  For example,
suppose a flight departed Denver bound for DFW and the pressurization
system had a fault after takeoff and merely kept the pressurization in
the cabin at the field elevation for Denver for the entire flight.
During the descent into Dallas, the outside air pressure would exceed
the inside air pressure.  To allow for the possibility, most transport
category jets have negative pressure relief panels somewhere on the
fuselage (on the B-727 and B-737, these panels are in the rear of the
aircraft) that will open inwards and allow the pressure to equalize
should the need arise.

Chris Dahler