Kegworth air disaster
{{Crash infobox|name=Kegworth Air Disaster|Date=
January 8 1989 |Type=Engine failure,
Pilot error|Site=Kegworth, Leicestershire|Fatalities=47 |Injuries=79 |Aircraft Type=Boeing 737-400|Operator=British Midland |Tail Number=G-OBME |Passengers=118|Crew=8 |Survivors=79 |The
Kegworth Air Disaster occurred on
January 8,
1989 when a
Boeing 737-400 crashed onto the embankment of the
M1 motorway in England. The plane, operated by
British Midland Airlines, was attempting to land at the
East Midlands Airport, located in
Leicestershire, close to the village of
Kegworth. The crash, which took place during
British Midland Flight 92, killed forty-seven people and seriously injured seventy-four, including seven members of the flight crew.
On January 8, the aircraft was on a scheduled flight from
London Heathrow Airport to
Belfast in
Northern Ireland, having already flown from Heathrow to Belfast and back that day. The plane was nearly brand new, only having been flown for 520 hours in total. After taking off from Heathrow at 7:52pm, the twin-engined plane was climbing through 28,300 feet to reach its
cruising altitude of 35,000 feet when the one of the fan blades on the left engine suddenly ruptured. While the pilots did not know the source of the problem, a sudden pounding noise, along with severe vibrations, suddenly appeared. In addition, smoke poured into the cabin through the ventilation system, and an aroma of burning entered the plane. Several passengers sitting near the rear of the plane noticed smoke and sparks coming from the left engine.
The flight was diverted to the East Midlands Airport, which was only a few minutes flight away and reachable with only one engine. However, the crew had misidentified the engine that had failed and had shut down the correctly functioning right engine.
After the initial blade fracture, the captain,
Kevin Hunt, had disengaged the plane's
autopilot. When Hunt asked the First Officer,
David McClellan, which engine was malfunctioning, McClellan replied: 'It's the le... it's the right one'. They had no way to visually check the engines from the cockpit and the pilots' limited experience and lack of training on the 2 month old aircraft contributed to them shutting down the working right engine instead of the malfunctioning left engine.
|
The scene of the disaster, with the runway that G-OBME failed to reach at the top of the picture |
When the pilots shut down the right engine, the smoke smell ceased, which confirmed in their minds that they had dealt with the problem. As it turned out, this was simply a fateful coincidence. When the
autothrottle was disengaged to shut down the right engine, the fuel flow to the left engine was reduced and the excess fuel which had been igniting in the jet exhaust disappeared; therefore, the ongoing damage was reduced, the smoke smell ceased, and the vibration reduced, although it would still have been visible on cockpit instruments.
However, during the final approach to the
East Midlands Airport, more fuel was pumped into the damaged engine to maintain speed, which caused it to cease operating entirely and burst into flame. The captain ordered the right engine to be started at this point via windmilling, using the air flowing through the engine to rotate the turbine blades and start the engine, but the aircraft was by now flying too slowly for this. The captain managed to keep the now-gliding aircraft airborne long enough to avoid a crash landing in the village of Kegworth by pointing the nose up and stretching the glide, but just before crossing the M1 motorway, the tail hit the ground and the aircraft bounced back into the air and over the motorway, crashing on the opposite embankment and breaking up into three pieces.
Forty-seven of the 118 passengers (126 people on board including flight staff) died (39 at the scene, 8 later). All eight of the flight crew survived the accident. Of the 79 survivors, 5 had minor injuries and 74 were seriously injured. Surprisingly, no one on the motorway was hurt (and no vehicles damaged) although one driver did subsequently receive damages for
post-traumatic stress disorder.
Shutting down the wrong engine
The captain (Kevin Hunt) believed the right engine was malfunctioning due to the smell of smoke, because in previous Boeing 737 variants,
bleed air from the engines for the air conditioning system was taken from this engine. However, starting with the Boeing 737-400 variant, Boeing redesigned the system so both engines fed it. Several cabin staff and passengers also noticed that the left engine had a stream of unburnt fuel igniting in the jet exhaust, but this information was not passed to the flight crew, because they thought that the pilots knew what they were doing.
Besides the unfortunate coincidence of the smoke disappearing when the autothrottle was disengaged to shut down the right engine, another problem may have been that pilots had got into the habit of disregarding the readings of vibration warning meters; early ones were unreliable but the flying crew of G-OBME do not seem to have been aware that newer ones were more reliable. The dials were also much smaller than the previous model of 737 that they had most of their experience on. The pilots had received no simulator training on the new model; no simulator for the 737-400 existed in the UK at that time.
Engine malfunction
It was discovered after analysis of the engine from the crash that the fan blades (LP Stage 1 compressor) of the uprated CFM56 engine used on the 737-400 were subject to abnormal amounts of vibration when operating at high power settings above 25,000 ft. As it was an upgrade to an existing engine, in-flight testing was not mandatory and as such, the engine was only ever tested in the laboratory. Upon this discovery all 737-400s (around 100 at the time) were grounded and the engines modified. Since the crash it has also become mandatory to carry out test at representative conditions for all
turbofan engines, whether they are a brand new design or a major redesign.
This unnoticed vibration created excessive
metal fatigue in the turbine blades and on G-OBME this caused one of the fan blades to break off and cause damage throughout the engine. This damaged the engine terminally and also upset its delicate balance, causing a reduction in power and an increase in vibration. The autothrottle attempted to compensate for this by increasing the fuel flow to the engine, however the damaged engine was unable to burn all the additional fuel, with much of it igniting in the exhaust flow, thus creating a large trail of flame behind the engine.
Evaluation of the injuries sustained led to considerable improvements in aircraft safety and emergency instructions for passengers. The official report into the disaster made 31 safety recommendations.
There is a memorial to "those who died, those who were injured and those who took part in the rescue operation", in the village cemetery in nearby
Kegworth, together with a garden made using soil from the crash site.
Hunt and McClelland were seriously injured in the crash, and were later dismissed following the criticisms of their actions in the
AAIB report.
*In the game,
Emergency Fighters For Life by Sixteen-Tons Entertainment, a plane crashed across a highway, and broke into three pieces.
*The
National Geographic Channel documentary series
Seconds From Disaster has an episode dedicated to the disaster; the third episode of its second season.
*
Lists of accidents and incidents on commercial airliners*Macarthur Job,
Air Disaster Volume 2: Aerospace Publications Pty Ltd, 1996, ISBN 1875671196, p173-185
*David Owen,
Air Accident Investigation: Patrick Stephens Limited, 2001. (The Kegworth air disaster is given a detailed mention in Chapter 9, "Pressing the Wrong Button")
*
The official AAIB report*
BBC Page about Kegworth*
Kegworth Village site*
BBC Site detailing the crash*
The story of Graham Pearson, who received damages in 1998 after witnessing the crash and helping the survivors
