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Date: Sun, 29 Jun 2008 21:18:15 -0400
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From: "Jeffrey Liegner, MD" <liegner@embarqmail.com>
Subject: Chelton as a Flight Data Recorder: Post Accident Analysis
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Our Chelton units are durable flight data recorders that frequently 
retain their data after a catastropic accident.  I recall in May 2003 
when the Chelton unit was pulled from the wreakage of my frined's 
Lancair IVP (N29ME) and given to Brent Regan for analysis, there were 
some graphic descriptions of the VSI shifts and G forces and roll 
angles and pitch changes that not only impressed me what happens 
inside a TStorm, but scared me to think that's what awaits us inside 
that IMC.  For example, Brent described one moment 5,328 fpm UP and 
the next moment 10,208 fpm DOWN with extremes in bank angle.

Here's the NTSB report:
http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20030520X00696&ntsbno=ATL03LA094&akey=1
The damaged Sierra Flight Systems navigation systems were forwarded 
to the Seattle Flight Standards District Office for further analysis 
by Regan Designs, Coeur-D"Alene, Idaho. The data cards were removed 
and the systems were downloaded after replacing damaged components. 
Review of information downloaded from the Sierra Flight Systems 
navigation system revealed the airplane was at 11,676 feet at 
1755:31. The airplane climbed up to 12, 236 feet at 1755:46, and 
entered a left spiraling dive. The last data point at 1756:01 shows a 
tightening left hand spiral dive with a true airspeed of 253, and a 
positive 3.75 G's.

I also recall that his description was later suppressed in an apology 
and an expression of regret that the Chelton data retreived was 
disclosed to us outside the NTSB process, conceiveably a "no no" by 
the bureaucracy.  
http://mail.lancaironline.net/Lists/lml/Message/19072.html

And so we get very little descriptive information in the NTSB reports 
about the sheer terror of the forces acting on the plane at the time 
of the accident event.  I think this is a missed opportunity, and 
would like to ask if others would also be interested in these 
details.  The NTSB excerpt above contains some of these Chelton 
details, but does not invoke the timeline and in the way that Brent 
Regan did many years ago.

The recent N101BX accident had a Chelton unit, as have many others. 
Perhaps there is a way to have this raw Chelton data available 
outside the NTSB, or have the more detailed interpretation of this 
data shared with us, so we can benefit from the recorded events.

I think there is a need for this type of detail beyond the NTSB 
summary report.  Does anyone agree, and does anyone know how to gain 
access to it?

As a footnote, I'm sure many ListServ members appreciate Brent 
Regan's contributions everytime he weighs in.

Jeff Liegner
LIVP


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<html><head><style type="text/css"><!--
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 --></style><title>Chelton as a Flight Data Recorder: Post Accident
Analysis</title></head><body>
<div>Our Chelton units are durable flight data recorders that
frequently retain their data after a catastropic accident.&nbsp; I
recall in May 2003 when the Chelton unit was pulled from the wreakage
of my frined's Lancair IVP (N29ME) and given to Brent Regan for
analysis, there were some graphic descriptions of the VSI shifts and G
forces and roll angles and pitch changes that not only impressed me
what happens inside a TStorm, but scared me to think that's what
awaits us inside that IMC.&nbsp; For example, Brent described one
moment 5,328 fpm UP and the next moment 10,208 fpm DOWN with extremes
in bank angle.</div>
<div><br></div>
<div>Here's the NTSB report:</div>
<div><font face="Lucida Grande" size="-1"
color="#000000"
>http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20030520X00696&amp;ntsbno=<span
></span>ATL03LA094&amp;akey=1</font></div>
<div><font face="Lucida Grande" size="-1" color="#000000">The damaged
Sierra Flight Systems navigation systems were forwarded to the Seattle
Flight Standards District Office for further analysis by Regan
Designs, Coeur-D&quot;Alene, Idaho. The data cards were removed and
the systems were downloaded after replacing damaged components. Review
of information downloaded from the Sierra Flight Systems navigation
system revealed the airplane was at 11,676 feet at 1755:31. The
airplane climbed up to 12, 236 feet at 1755:46, and entered a left
spiraling dive. The last data point at 1756:01 shows a tightening left
hand spiral dive with a true airspeed of 253, and a positive 3.75
G's.</font></div>
<div>&nbsp;</div>
<div>I also recall that his description was later suppressed in an
apology and an expression of regret that the Chelton data retreived
was disclosed to us outside the NTSB process, conceiveably a &quot;no
no&quot; by the bureaucracy.&nbsp;<font face="Lucida Grande"
size="-1" color="#000000">
http://mail.lancaironline.net/Lists/lml/Message/19072.html</font></div
>
<div><br></div>
<div>And so we get very little descriptive information in the NTSB
reports about the sheer terror of the forces acting on the plane at
the time of the accident event.&nbsp; I think this is a missed
opportunity, and would like to ask if others would also be interested
in these details.&nbsp; The NTSB excerpt above contains some of these
Chelton details, but does not invoke the timeline and in the way that
Brent Regan did many years ago.</div>
<div><br></div>
<div>The recent N101BX accident had a Chelton unit, as have many
others.&nbsp; Perhaps there is a way to have this raw Chelton data
available outside the NTSB, or have the more detailed interpretation
of this data shared with us, so we can benefit from the recorded
events.</div>
<div><br></div>
<div>I think there is a need for this type of detail beyond the NTSB
summary report.&nbsp; Does anyone agree, and does anyone know how to
gain access to it?</div>
<div><br></div>
<div>As a footnote, I'm sure many ListServ members appreciate Brent
Regan's contributions everytime he weighs in.</div>
<div><br></div>
<div>Jeff Liegner</div>
<div>LIVP</div>
<div><br></div>
<div><br></div>
<div><br></div>
<div><br></div>
<div><br></div>
<div><br></div>
<div>&nbsp;</div>
<div><font face="Lucida Grande" size="-1"
color="#000000"><br></font></div>
</body>
</html>
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