Computer-Related Incidents with Commercial Aircraft

The A300 Crash in Nagoya

26 April 1994

Synopsis A China Airlines A300 (a non-`fly-by-wire' Airbus) crashed on landing at Nagoya in Japan. It turns out that the pilot flying had inadvertently triggered the `go-around' mode, as noticed by the captain (the non-flying pilot) but did not disconnect the autopilot, despite repeated instructions from the captain to do so (the A300 Operations Manual explicitly requires the pilot to disconnect the autopilot in such circumstances) until 40 seconds after it was noticed. The pilot flying tried to force the nose of the airplane down, and the autopilot, in go-around mode, reacted to the lack of climb by trimming pitch even further up. When the pilot eventually stopped pushing and the AP was disconnected, the captain took over. However, without the forward pressure on the yoke, the nose rose sharply, due to the extreme nose-up trim, and the plane stalled in an extreme nose-high configuration, and hit the ground tail-first. There were early rumors of unusually high levels of blood alcohol in the pilots' bodies (more than is expected as a natural by-product of death), and a complete power failure before the crash, but neither of these figured in the final report. The question, why the pilot flying did not disconnect the autopilot as he is required to and was instructed to multiple times, probably cannot be answered. As a result of this accident and other recent incidents and accidents, the US FAA started to `work with' China Air on its pilot training programs. final report (HTML) is large. The HTML version has been prepared for the WWW by Hiroshi Sogame of the Safety Promotion Committee of All Nippon Airways and Peter Ladkin. The Appendices, Photographs and Figures from the report have been prepared for the WWW by Marco Gröning. Included with the Appendices and Figures are HTML versions of the CVR transcript and (the English version of) the letter from the French Bureau Enquêtes Accidents, prepared for the WWW by Hiroshi Sogame of All Nippon Airways and Karsten Loer. [There are over 100 figures and photographs. The FDR charts have not yet been included, but will appear shortly. PBL]

The short paper WB-Graph of the A300 Accident at Nagoya contains the textual form of a WB-Graph causal analysis of the events and states in the Nagoya Report, prepared by Peter Ladkin and Karsten Loer. WB-analyses determine the causal relations between the events of an accident according to a rigorous formal semantics, and may provide insight into the accident.

For those without the desire to wade through the entire report, a synopsis and commentary on the final report is based on an article in Aviation Week and Space Technology, July 29th, 1996 issue. The final report contained no surprises, based on what was known shortly after the accident.

A note on the accident report appeared in RISKS-18.33. Early discussion of this accident in RISKS in 1994 led to much discussion about Airbus aircraft and accident statistics in general:
China Airlines A300 Crash by Mark Stalzer;
Re: China Air ... by David Wittenberg;
More on the A300 crash ... by Peter Ladkin;
Re: China Airlines ... by John Yesberg;
Re: China Airlines ... by Mark Terribile;
How to feel safer in an Airbus by Peter Ladkin;
Airbus A3(0?)0 deductions by Phil Overy;
Further Discussion by Mary Shafer, Robert Dorsett, Phil Overy and Wesley Kaplow;
Further Discussion by Robert Dorsett, Peter Ladkin, Wesley Kaplow, Peter Mellor and Bob Niland;
Summary of Safety-Critical Computers in Transport Aircraft by Peter Ladkin;
A320 Hull Losses by Peter Mellor.