Re: [sc] A320 crash at Habsheim.



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From: Peter B. Ladkin (ladkin(at)rvs.uni-bielefeld.de)
Date: Wed 28 Aug 2002 - 15:01:25 BST


Mark,

> ... I have tried to look up on the Internet what the conclusions 
> [of the Habsheim accident investigation ]were 

As far as I know, the report is on the BEA site. Here is Section 3.2

3.2.1 Cause 

 "......a combination of the following conditions:

 * very low flyover height, lower than surrounding obstacles

 * speed very low and reducing to reach maximum possible angle of attack
 
 * engine speed at flight idle

 * late application of go-around power

This combination of conditions led to impact of the aircraft with the
trees.

The Commission also believes that if the descent below 100 feet was nmot
deliberate, it may have resulted from failure to take proper account of
the visual and aural information intended to give the height of the
aircraft."

3.2.2 Other factors:

"... the following factors contributed towards placing the crew in a
situation that they were not able to fully control:

 * The flight preparation was insufficient, especially due to the
   brevity and late provision of the brief and of the information
   about the airshow.

 * The task sharing lpanned for the flyover by the crew was incomplete
   and was not followed

 * The holiday atmosphere for the passengers and spectators could have
   been transmitted to the Captain.

 * These new features of the aircraft had sometimes been criticized and
   the Captain wanted to defend the aircraft.

 * Neither of the two pilots had previous experience of demonstration
   flights.

 * The late identification of the [Mulhouse-Habsheim] aerodrome led to
   a rush of events, and the making of the descent and then the complete
   flyover above the runway with the engines at flight idle, and without
   stabilizing the flight parameters.

 * Neither of the two pilots had previous experience of applying
   go-around power from flight idle in similar conditions. "

That's it.

There is a summary and WBG of the causes according to the report in
my Safecomp 2000 paper Causal Analysis of Aircraft Accidents on my
WWW site -> Publications -> Publications of Record.

> Some blame the pilot for poor attitude to the flight others reiterate 
> problems with the altimeter and may be the engines and others are
> claiming that the Lausanne Institute of Police Forensic Evidence and
> Criminology have proved, in May 1998, that the black boxes were
> switched.

Well, the flight planning was a mess (he planned stuff that broke
French airshow regs and Air France approved it anyway. He didn't
know the airfield, hadn't looked at it from ground or air, and didn't
know in advance which runway he was going to perform his flybys along).

The flight execution was a mess. The videos show clearly that he
wasn't stabilised until after he broke his planned 100ft altitude.
Besides, simple physics says that you cannot go up from 30 ft altitude
at minimum airspeed and engines at flight idle. You are at minimum 
kinetic energy and have no potential energy.

He had two altimeters, namely a radio altimeter and a barometric 
altimeter. Not only that, but the barometric is duplicated (I've
forgotten how many the A320 has, but the B757 for example has three
systems).

Switching the black boxes after the accident has, causally, nothing to
do with the accident.

The pilot acknowledges all these assertions. But he said that he
commanded go-around before the DFDR readout says he did, that the
engines did not spool up within the specified 8 seconds or whatever
it is from 29% N1 to 80% N1, and that a 4-second fragment was 
excised from the DFDR readout to make it appear as though they did.

I don't know the current state of the discussion of these assertions.
Likely Pete Mellor does.

PBL

-- 
Peter B. Ladkin PhD FBCS CW(hon)
Professor of Computer Networks and Distributed Systems,
Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany
Tel (Vx/msg/Fax) +49 (0)521 880 7319 http://www.rvs.uni-bielefeld.de
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