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Computer-Related Incidents with Commercial Aircraft

Non-Computer-Related Automation Problems

In view of recent incidents and accidents to the Airbus A320, A330 and A340 fly-by-wire aircraft, it is as well to remember that there has been hydro-mechanical (analogue! :-) control automation on aircraft for a long time, and this sort of automation can also have its problems. One view held by many in the industry is that computers alone alleviate more risks than they pose. A more sophisticated view would measure on something different from an ordinal scale the risks involved in the increasing uses of digital computers in avionics. (An ordinal scale is a scale on which every two states are in the relation `more' or `less' or `equally' to each other. See the classical work Foundations of Measurement Theory, Vol. 1 by D. H. Krantz, R. D. Luce, P. Suppes, and A. Tversky, Academic Press, 1971.)

The Boeing B737 and Airbus A320 are rival airplane series. The A320 is the subject of many reports in this compendium. The B737 has recently come under investigation for suspected and reported rudder-control anomalies. Some investigators suspect that such anomalies may have played a role in the unexplained crashed of United Airlines Flight 585 on 3 March 1991 near Colorado Springs, and USAir 427 on 8 September 1994 near Pittsburgh. The NTSB has prepared an extensive report on its investigations, released at a public meeting on 16 October 1996, which contains recommendations A-96-107 through A-96-120.