<Presentation>, 2008 Slide 1

Kegworth Air Disaster

<Presentation>, 2008 Slide 2

The Kegworth Air Disaster• 8th January 1989

• British Midland Flight 92– Heathrow to Belfast

• Boeing 737-400– New variant of Boeing 737

• Crashes by the M1 near Kegworth, attempting an emergency landing at East Midlands Airport

• 118 passengers, 8 Crew– 47 die, and 74 seriously

injured

<Presentation>, 2008 Slide 3

The Kegworth Air Disaster• The left engine was

unable to cope with the vibrations caused when operating under high power settings above 25,000 feet.

• A fan blade broke off, causing an increase in vibration, reduction in power, and there was a large trail of flame behind the engine.

• The pilot shut down the engine on the right. • The plane flew for another 20 minutes until the left engine failed

<Presentation>, 2008 Slide 4

Right engine shutdown

• Mistake in knowledge based performance - Smoke in the cabin indicates that the engine from which bleed air (used for heating, pressure, etc) is taken will have smoke in it. But, the pilot thought bleed air was taken from the right engine. This is true of the Boeing 737 but not the new 737-400, which drew bleed air from both.

• Design issue - No visibility of engines, so relied on other information sources to explain vibrations

• Design issue – The vibration sensors were tiny, had a new digital display style and were inaccurate on the 737 (not the 737-400)

• Inadequate training - A one day course, and no simulator training

<Presentation>, 2008 Slide 5

Failure to detect error

• Coincidence – The smoke disappeared after shutting down the right engine and the vibrations lessened. “Confirmation bias”.

• Lapse in procedure – After shutting down the right engine the pilot began checking all meters and reviewing decisions but stopped after being interrupted by a transmission from the airport asking him to descend to 12,000 ft.

• Lack of Communication - The cabin crew and passengers could see the left engine was on fire, but did not inform the pilot, even when the pilot announced he was shutting down the right engine.

• Design Issue – The vibration meters would have shown a problem with the left engine, but were too difficult to read. There was no alarm.

<Presentation>, 2008 Slide 6

Cock

pit

of

a B

oein

g 7

37

<Presentation>, 2008 Slide 7

Cockpit of a Boeing 737-400

<Presentation>, 2008 Slide 8

Cockpit of a Boeing 737-400

<Presentation>, 2008 Slide 9

Conclusion

• Pilot error?

• Crew training?

• User interface design?

• Aircraft design?

• Engineering problems?

• Lack of proper training?

<Presentation>, 2008 Slide 10

Failures are rarely ever simple!

The problem is complexity