Alan Cooper, whose consulting firm, Cooper, in Palo Alto, Calif., helps companies make their technical products easier to use, said the profusion of digital options often creates what he calls "mode confusion." This syndrome is known to afflict pilots who become dangerously befuddled by on-board automation, where a single control or sign could do or mean two different things.

Aviation computer experts involved in the legal action brought by relatives of some of the victims of the crash against Chinese Airlines and Airbus Industrie will argue the crew was suffering from ''mode confusion'' — not understanding the status of the computer — and its design may be partly to blame.

The US Federal Aviation Administration is beginning a year-long study of modern airliner cockpit-design following concerns raised by recent accidents. …

There have been accidents in which pilot flight-mode confusion is known, or believed to have been a contributory factor. These include the 20 January, 1992, Air Inter A320 crash on approach to Strasbourg, France (in which there were 88 fatalities) and the 26 April, 1994, China Air Lines A300-600 accident at Nagoya, Japan, in which 264 people died.

Several serious, but non-fatal incidents involving various types have also been judged by investigating authorities to be attributable to mode-confusion.