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From: Robert Dorsett <>
Subject: MD-11 (Re: hydraulic problems on DC-10)
Date: 10 Dec 92 20:58:52 PST

In article <airliners.1992.133@ohare.Chicago.COM> pab@po.CWRU.Edu (Pete
Babic) writes:

>Does anyone know if the MD-11 has a proper locking mechanism for the slats?
>I'm a layman when it comes to aircraft design, but the DC-10 really looks
>like a substandard design that has killed a bunch of people due to cost
>cutting short cuts.

I had wondered about this, and researched it about a year ago.  I wasn't
able to find a clear-cut answer.

Otherwise, my conclusion is that the MD-11 is a very marginal upgrade of the
basic DC-10 design.  The systems layout is almost identical; none of the major
"complaint areas" have changed.  There's a high degree of commonality between
the DC-10 and MD-11, the "hydraulics plug" adopted after the SUX crash being a
good example.

The changes incorporate a 6-meter fuselage stretch, the winglets, composites
in the tail, new engines, and a new cockpit.  The latter appears to be the
most radical change, but other than that, what characterizes the industry
media is a lot of manufacturer "gee whiz" propaganda, long on "radical
changes," but short on specifics.

I recall an Av Leak article a couple of years ago, which suggested the
full new type-certification wasn't necessary, but McDonnell-Douglas did it
anyway, to try to exorcise itself from the political "ghosts" of the DC-10:
a regulatory face-lift, if you will.  Problem is, not much has changed.

So: I see no objective reason to conclude the MD-11 is any "safer" than the
DC-10, if one accepts the existence of the problems that characterized the
DC-10's development.

More detailed information would be welcome.  I was really appalled by how
little "hard" info was out there, and I spent quite a bit of time on it.
Literally hundreds of articles on 767-X and 777 aerodynamic and systems
development, dozens on Airbus, but only two or three "skimpy" treaments on
the MD-11, the kind of things you'd find in "Aerospace America."  Does MDC
have some kind of anti-publishing policy or something?

Robert Dorsett

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