Computer-Related Incidents with Commercial Aircraft

British Midland B737-400 at Kegworth

8 January 1989

Synopsis A Boeing 737-400 operated by British Midland Airways Ltd crashed short of East Midlands Aerodrome on an emergency approach with engine problems. The airplane crashed across the M1 motorway, coming to rest partly on the motorway embankment. G-OBME left Heathrow Airport at 1952hrs with 118 Passengers destined for Belfast. Climbing through 28,300 feet, a portion of a blade in the left (No. 1) engine 1 detached. This resulted in engine vibration and smoke, and fluctuations in the engine instruments. The crew misdiagnosed a fire in one of the two engines. The crew misidentified the source, throttled engine 2 back and shut it down. As engine 2 closed down, engine 1 stabilised, falsely confirming to the crew that they had acted correctly. The aircraft made an emergency diversion to East Midlands Airport, near Kegworth, Leicestershire, adjacent to the M1. The aircraft intercepted the Rwy 27 localizer 6nm from the threshold, for an ILS approach. During final approach, the engine vibrations resumed, leading to a loss of power and the crew were unable to maintain glideslope. The final report, AAIB Accident Report 4/90, Report on the accident to Boeing 737-400 G-OBME near Kegworth, Leicestershire on 8 January 1989 is available on the WWW. We have prepared an extract of the most relevant information concerning the automation. It is notable for investigating the digital presentation of engine status information in the `glass cockpit' 400-series B737; and also for being the only accident I am aware of in which a mistaken crew action correlated with a `false positive', a simultaneous event which mistakenly seemed to confirm that the action they had taken was right.