Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml@lancaironline.net
Date: Sat, 20 Sep 2003 17:09:01 -0400
Message-ID: <redirect-2587085@logan.com>
Reply-To: "Skip Slater" <skipslater@earthlink.net>
From: "Skip Slater" <skipslater@earthlink.net>
References: <list-2586174@logan.com>
Subject: Re: [LML] Legacy accident
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I'm sure Ron's accident has stirred a great deal of thinking among many of
us on the list.  Ron, I saw your plane in Reno and remarked to my wife how
beautiful it was.  I share the thoughts of those who have expressed their
deep regret at the loss of your plane as well as the profound relief that
you were able to walk away from the accident.

Turning to the circumstances of this incident, I've tried to put myself in
Ron's place and think of what I'd have done if the seat of my pants told me
the plane was ready to fly, yet two different airspeed indicators (IAS and
AOA) were telling me it wasn't.  I can't say with certainty what I'd have
done.  In every other plane I've flown that has angle of attack, it's the
first thing I've been trained to go to with a blocked pitot or static source
that renders the airspeed indicator useless.  It wasn't until Ron's accident
that it occured to me that the AOA indicators we get from Jim Frantz, while
a great tool, are also dependent on unblocked pitot and static sources.
With all of the redundencies we try to build into our planes (including dual
static sources in most cases) the pitot tube stands out as a single point of
failure that can ruin your whole day.  Unless we build in a second,
separately plumbed pitot tube for our AOA input or for a second airspeed
indicator such as the RMI micro encoder, this will remain a weak spot.  As
it is now, if one indication is bad, the other probably is as well.

In considering what other resources we have to determine our speed in a case
such as this, the only other one I can think of is the groundspeed readout
from our GPS.  Most of us have GPS and most of us have a groundspeed display
available to us most of the time.  While it will differ from IAS by the
amount of wind component you're dealing  with  (which is often a known
entity) and may lag by a few seconds, it will certainly be better than
nothing.  In light of Ron's unfortunate mishap, I now plan to  immediately
cross-check my GPS groundspeed readout should I ever have a suspect airspeed
indication.

If anyone else has any other ideas along these lines, I hope you'll share
them with the rest of the LML readers.  I think we're all in Ron's debt for
having shared the details of what happened to him.

Skip Slater