Re: New ground proximity warning.

Date:         27 Dec 96 04:41:06 
From:         faurecm@halcyon.com (C. Marin Faure)
Organization: Northwest Nexus Inc.
References:   1 2 3 4
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In article <airliners.1996.2850@ohare.Chicago.COM>, Steve D White
<steve@sdwhite.demon.co.uk> wrote:

> In article <airliners.1996.2764@ohare.Chicago.COM>, "C. Marin Faure"
> <faurecm@halcyon.com> writes
> >I agree that relying on a new, gee-whiz technology or systems is not a
> >guarantee of safety.  But anything that gives the pilots more information
> >about their airplane's relationship to the potential terrain dangers
> >around them is a good thing as far as I'm concerned, and well worth the
> >cost and effort to install.  Apparently, this same system is being
> >installed by American Airlines and United as well as Alaska.  I wish I had
> >it in the de Havilland Beaver floatplane I fly.  But I can't complain; at
> >least it has a com radio...
>
> As a person that works in aircraft safety, I get very twichy when people
> start saying thing like this.  Who verifies that the database is
> correct? What happens if the terrain changes? The problem this systems
> of this sort is that the crew become to rely on them and then when
> things go wrong it is put down to pilot error!

If this logic were followed to extent you seem to believe, then it seems
VOR, DME, GPS, ILS, inertial nav, radar, collision avoidance, ground
proximity, and radio altimeters should never have been installed in
commercial aircraft in the first place.  As soon as all these things
became available, airline pilots started depending on them and they still
do every minute of every flight.

Verification of terrain can be performed as often as you like with
satellites, and it's unlikely that a mountain or a ridge is going to
suddenly disappear without someone knowing about it.

C. Marin Faure
   author, Flying a Floatplane