From: amm@NeXT.COM (Alan M. Marcum)
Newsgroups: rec.aviation.piloting
Subject: A320 descent anomalies reported in French press
Date: 20 Nov 92 22:31:35 GMT
Reply-To: amm@NeXT.COM (Alan M. Marcum)

Following is from the ACM RISKS forum.

Date: Tue, 17 Nov 92 17:33:30 GMT
From: Pete Mellor <pm@cs.city.ac.uk>
Subject: A320 descent anomalies reported in French press

      ---------------------------Le Monde------------------------

Translated from Le Monde, 10-30-92 from the "Faits Divers" column.
Translation by John Lupien (jrl@world.stdl.com)

      Incident during the descent of an Airbus A-320 of Air Inter 
      -----------------------------------------------------------

The crew of an Airbus A320 who were making in September a flight
between Clermont-Ferrand and Paris-Orly were surprised to witness
an aberration in the vertical speed of descent of the equipment.
Having chosen a mode of descent of 550 meters per minute, they
noticed that the plane was losing 750 meters per minute, and that
when they tried to correct that value to 450 meters per minute,
the rate worsened to 850 meters per minute.  The pilots at that
point changed their procedure and chose an angle (rather than a
rate) of descent and everything went back to normal.

The cause of the incident can be imputed to defective design in
the interface between the flight controller and the auto-pilot,
both developed by the French Sextant-Avionique and by the German
BGT and with which other types of planes such as the Airbus A-300
and A-310 are equipped with. This kind of fault is not frequent,
but it is one of the anomalies that the crew is trained to
correct.

This incident would have passed unnoticed if certain pilots had
not made it public to point out a relationship to the aerial
catastrophe of Mount Saint-Odile which happened in January, when
87 persons were killed in the crash of an Airbus A-320 of Air
Inter. The first findings of the commission of inquiry had perhaps
made it appear that the crew was mistaken in the choice of descent
mode towards the airport of Strasbourg and that they had not
monitored their trajectory.

Translator's comment - The translation is as literal as I could
manage...  Certain bits such as "esquisser un rapprochement"
perhaps translate not so well...

      ---------------------------End Le Monde------------------------- 

      -----------------------------Figaro----------------------------- 

Translated from Le Figaro, 10-30-92 from the "En Bref" ("In
Brief") column.  Translation by John Lupien (jrl@world.std.com)

                              AIRBUS 

                     Electronics in question
                     -----------------------

Judge Francois Guichard, in charge of the investigation of the
accident of Mount Saint-Odile, which killed 87 last January 20,
indicated on Thursday evening in Toulouse that the recent incident
in the descent mode of an A320 of Air Inter "Could a priori appear
to be one of the reasons that caused the accident". The magistrate
referred to the failure of the electronic control systems for the
mode of descent of an A320 of Air Inter which, in September, took
a much steeper descent than that chosen [by the pilots].

         ----------------------end Figaro--------------------------

My thanks to John for these two translations. 

Peter Mellor
Centre for Software Reliability
City University
--
Alan M. Marcum
NeXT Tech Support
amm@NeXT.COM