Re: AA changes rules after BDL incident

From:         amb@cs.columbia.edu (Andrew M. Boardman)
Organization: Slug Hordes of the Planet Gamma
Date:         21 Dec 95 03:33:10 
References:   1 2
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Andrew Goldfinger  <Andy.Goldfinger@aplmail.jhuapl.edu> wrote:
>Does this mean that an aircraft flying a proper approach would have
>cleared the ridge by only 180 feet?  Isn't this too close for comfort?

Actually, I've got the approach plate in front of me, and the ridge is
marked at 819' +/-.  The MDA is, indeed, 1080', leaving a scant margin
of 261'.  The ridge is also only about 1.5 miles beyond the FAF, which
needs to be crossed at 2000', which indicates a pretty steep descent
to get down to the MDA, even with 0.3" Hg of altimiter error.  I'd
expect, considering today's accident driven FAA, that we're going to
see another stepdown fix in the near future keeping aircraft higher
over the ridge until after they've passed it on this approach.

It looks like this is another case of an accident being caused by the
snowballing of otherwise manageable factors; I *am* curious what
source AA crews use for QFE, and if that source (if they're not
calculating it themselves) was on a slower update cycle than the
well-distributed QNH.  (Do ATC units have fingertip access to QFE?)

Time (and the NTSB) will tell...

andrew