Re: Emergency exits capacity

From:         bradg@io.org (Brad Gillies)
Organization: Leading Edge Aviation Services
Date:         18 Sep 95 12:06:49 
References:   1
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In article <airliners.1995.1437@ohare.Chicago.COM>,
   mezei_jf@eisner.decus.org (Jean-Francois Mezei) wrote:
>I have a few question on emergency exits for airplanes :
>
>Is the "must be able to empty plane in 90 seconds" a real requirement or just
>urban legend ?
>
>Are there specific and widely accepted ways to measure each exit's capacity in
>an emergency ? If so, what are the criteria used ? (door size, chute length,
>cabin/aisle design ?) Or do aircraft manufacturers actually load up a plane
>with people and make the test ?
>
>Does anyone have specific numbers on how many passengers a full fledged door
>(with chute) can process (per minute ?) and how over-wing exits fair in that
>regard ?
>
>If the "90 seconds" requirement is true, does it apply to a plane with all of
>its doors usable, or does it assume that a certain percentage of its doors will
>be unusable ?

THe requirement is for 90 second evacuation with half of the doors
inoperative.

THe tests are conducted with real people in a cabin mockup with smoke and
all but this is not really atrue test as people react much differently
when they are actually in danger of dying.  I do not have specific numbers
but I'm sure over the last 50 or so years the enginneers have compiled
enough data to be able to plan the required exits and their positions.

NOTE: On aircraft in service, if a door is not operative the plane can
not carry passengers in the area adjacent to the exit. THe actual number
of passengers that are not boarded obviously depends on the type of
aircraft.

Hope that helps.

--
Brad Gillies    Bradg@io.org
http://www.io.org/~bradg/
Leading Edge Aviation Services
Aviation Maintenance, The Backbone of Aviation.