Re: exit door latch

From:         Nicolas Ercan Murat <vis@amy29.Stanford.EDU>
Organization: Stanford University
Date:         11 Sep 95 21:27:26 
References:   1 2 3
Followups:    1
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On 8 Sep 1995, Brandon M Walts wrote:

> >someone opening a hatch in flight is cabin pressure.  A 2' x 4' overwing
> >exit hatch has around 8 lbs/sq in holding it closed, and that translates
> >to over 4 tons!  I don't know of anyone strong enough to move that sort
> >of weight.  Once the aircraft is depressurised after it leaves the runway
> >after landing, the hatch could then be opened as the pressure on either
> >side has been equalised.

> On a related note, what's the case with outward-opening doors, like
> the kind on Airbus aircraft, airstair doors, etc.?  On a couple of
> occasions, while flying on A300s, the rear galley/lavatory area
> turned into a makeshift bar and gathering spot, often with people
> standing inches from the door handles.  I was personally worried by
> this, and wondered if there was something that kept doors of this
> type from being opened in flight.

As in the earlier case, the pressure differential and door mechanism will
not let door open so easily while in flight.  This was proven when an
evacuation slide on an PIA A310 decided to inflate during flight.  The door
opening handle on all airbus' is a long metallic handle that is lifted
from down to up (as opposed to the Boeings and MD where is anti/clockwise
180 degree motion).  So when the slide began inflating, it crew out of
the packboard and decorative cover and started lifting the door handle
towards "open".  Now, the force required was so high that the door warped
and bent rather than the opening the door.  Also, any movement on the
handle (however small) generateds an ECAM message on the flight deck.
The end of the story was that an on-board mechanic ran back and gave a big
stab with his screwdriver and punctured the slide.  Bottom line is that, at
cruising altitude, no way the door is going to open so easily.

Nick
Cabin Interior & Payload Systems