The Incident
On 8th January 1989 a Boeing 737-400 aircraft left Heathrow airport for Belfast with 8 crew members and 118 passengers on board. About 20 miles from the East Midlands Airport the engine began vibrating and there was a smell of burning. The crew believed this to be coming from the right hand engine, number 2, and shut down the engine. They also decreased the power to engine number 1 on the left side. As the smell of burning and the vibration decreased, they believed they had solved the problem, but decided to make an emergency landing at East Midlands Airport.
On approach to East Midlands Airport the crew increased the power to the left hand number 1 engine and found that the vibration increased and there was a loss of thrust followed by a fire warning from engine number 1. At this point they were between two and four miles from East Midlands airport, the crew attempted to raise the nose of the aircraft but failed to do so and crash landed in the embankment of the Northbound carriageway of the M1 just outside of Kegworth in Leicestershire.
The fuselage broke into three parts, and debris was scattered widely. 47 people died and 67 people were seriously injured. Witnesses on the ground claimed that engine number 1 was on fire.
The Causes
Engine number 1 was found to be the cause of the accident. There was damage to the fan blades caused by the ingestion of hard objects. One of the fan blades had metal fatigue and had cracked. There was evidence of fire damage to the engine casing. However, engine number 2 had no damage.
Air Accident Investigation Branch (1990) concluded that the crew had responded incorrectly, and that they were not trained to deal with engine vibration, noise and burning.
They shut down engine number 2 prematurely, and contrary to their general pilot training they didn’t assimilate the information on the AVM’s before throttling back number 2 engine. They believed they had made the correct decision when the vibration decreased even though the AVM indicated otherwise. Therefore, the AVM instrument and the attitude of the crew played a pivotal role in the cause of the accident.
The Air Accident Investigation Board (1990 p 115) said that regulatory requirements of new instrument presentations should be amended to include a standardised method of assessing the effectiveness of displays in transmitting information to the flight crew under normal and abnormal parameter conditions.
The CAA should require that the engine instrument System on the Boeing 737-400 aircraft type should be modified to include an attention gaining facility to draw attention to each vibration indicator when it indicates maximum vibration.
Conclusion
The Air Accident Investigation Branch raises a number contributing factors in their investigation including a gap in staff training and a lack of standardisation in aircraft displays.
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