Re: Boeing 777 Cabin Door

Date:         02 Apr 98 01:24:03 
From:         faurecm@halcyon.com (C. Marin Faure)
Organization: NorthWest Nexus Inc.
References:   1 2 3
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In article <airliners.1998.546@ohare.Chicago.COM>, procida@cardiff.ac.uk (D.M. Procida) wrote:
> C. Marin Faure <faurecm@halcyon.com> wrote:
>
> > Our design was put to the test ... an airport technician accidentally cut
> > the hydraulic pressure to the jetway.  It started to sink down on its
> > wheels and in the process neatly peeled the forward door right off the
> > 777.  But the shear mechanism worked as designed; the door ripped off and
> > fell onto a baggage cart down below, but there was no damage at all to the
> > door frame, skins, or surrounding airplane structure.
>
> Isn't this potentially dangerous, given that there are likely to be all
> kinds of people wandering around down below? What are the insurance
> implications of designing part of an aircraft so that it might fall off
> in such a fashion? On the other hand, it's not easy to see what is to be
> done about it. After all, a different design of door might damage a
> large part of the fuselage and *then* break off and fall onto the
> ground-crew...

Yes, it is potentially very dangerous, particularly to anyone who might be
under the jetway.  My understanding, however, is that in the WA-001
(prototype 777) incident I described earlier, the hydraulic system of the
jetway bled off fairly slowly and the jetway sort of sank down the side of
the plane rather than dropped abruptly.  The Boeing personnel on the plane
had just gotten off when the incident occurred.

When this occurs on planes other than the 777, I've been told that the
door often still breaks off the plane and falls down below or into the
jetway.  The difference is that on the 777, the departing door leaves no
structural damage behind.  As for the insurance aspect, well, I guess ramp
personnel shouldn't walk under the jetways, the same as they shouldn't
walk in front of or behind idling engines or they shouldn't put their hand
on an antenna on the belly of a plane that is marked "DANGER: HOT."  Most
of the airports I've been filming on recently paint warning stripes under
the operating area of the jetway, and in some places I have seen signs
warning people to keep clear of the area.  Presumably, the people
authorized to work on an airport ramp know about the potential danger of
all the equipment used, some of which presents a far greater risk on a
daily basis than the relatively remote possibility of having an airplane
door drop on your head.  But the possibility is always there.

C. Marin Faure
  author, Flying A Floatplane