Kegworth air disaster

The Kegworth air disaster occurred when British Midland Airways Flight 092, a Boeing 737-400, crashed onto the motorway embankment between the M1 motorway and A453 road near Kegworth, Leicestershire, England, while attempting to make an emergency landing at East Midlands Airport on 8 January 1989.

The aircraft was on a scheduled flight from London Heathrow Airport to Belfast International Airport. When a fan blade broke in the left engine, smoke was drawn into the cabin through the air conditioning system. The pilots believed this indicated a fault in the right engine, since earlier models of the 737 ventilated the cabin from the right, and they were unaware that the 737-400 used a different system. The pilots retarded the right thrust lever and the symptoms of smoke and vibration cleared, leading them to believe the problem had been identified, and then the right engine was shut down.

On the final stage of the approach, thrust was increased on the left engine. The tip of the fan blade that had lodged in the cowling from the earlier event became dislodged and was drawn into the core of the engine, damaging it and causing a fire.

The fan blade had initially suffered a fracture caused by aerodynamic flutter. This knowledge made clear that static ground testing to discover the presence of flutter was unreliable and the fan blade had to be subjected to the full flight envelope to be certain of the test results.

The accident was the first hull loss of a Boeing 737 Classic aircraft, and the first fatal accident involving a Boeing 737 Classic aircraft. Of the 126 people aboard, 47 died and 74 sustained serious injuries.

Accident

After taking off from Heathrow at 19:52, Flight BD 092 was climbing through 28,300 ft to reach its cruising altitude of 35,000 ft when a blade detached from the fan of the port (left) engine. The pilots did not know the source of the problem, but heard a pounding noise, accompanied by severe vibrations. Smoke poured into the cabin through the ventilation system, and passengers became aware of the smell of burning. Several passengers sitting near the rear of the plane noticed smoke and sparks coming from the left engine. The flight was diverted to nearby East Midlands Airport at the suggestion of British Midland Airways Operations.

After the initial blade fracture, Captain Kevin Hunt, the non-handling pilot, took control without first advising McClelland, and disengaged the plane's autopilot. Hunt then asked First Officer David McClelland which engine was malfunctioning, McClelland replied: "It's the le... It's the right one". In previous versions of the 737, the right (number 2) engine supplied air to the flight deck. The pilots had been used to the older version of the aircraft and did not realise that this aircraft was different. The captain later claimed that his perception of smoke as coming forward from the passenger cabin led them to assume the fault was in the right engine. The pilots throttled back the working right engine instead of the malfunctioning left engine. They had no way of visually checking the engines from the cockpit, and the cabin crew – who did not hear the captain refer to the right hand engine in his cabin address – did not inform them that smoke and flames had been seen from the left engine.

When the pilots restarted the right engine, they could no longer smell the smoke or feel the vibration, which led them to believe that they had correctly dealt with the problem. As it turned out, this was due to a combination of the Power Management Control unit and autothrottle which was disengaged prior to shutting down the right engine, the fuel flow to both engines was reduced, and the excess fuel, which had been igniting in the left engine exhaust, disappeared; therefore, the ongoing damage was reduced, the smell of smoke ceased, and the vibration reduced, although it would still have been visible on cockpit instruments which were "at best unclear and at worst misleading" according to Roger Green from the RAF Institute of Air Medicine.

During the final approach to the East Midlands Airport, the pilots selected increased thrust from the operating, damaged engine. This led to an engine fire, caused by the tip of the fan blade dislodging from the cowling, going into the core of the engine and causing it to cease operating entirely. The ground proximity warning system activated, sounding several "glideslope" warnings. The pilots attempted to restart the right engine by windmilling, but the aircraft was by now only 275 metres (900 feet) above the ground and flying too slowly for a restart. At 20:24:33, Captain Hunt broadcast to the passengers via the aircraft's public-address system: "Prepare for crash landing", instructing passengers to take the brace position. The stick shaker then activated. Just before crossing the M1 motorway at 20:24:43, the tail and main landing gear struck the ground at a speed of 213 km/h and the aircraft bounced back into the air and over the motorway, knocking down trees and a lamp post before crashing on the far embankment around 475 m short of the active runway's paved surface and about 630 m from its threshold. The aircraft broke into three sections. This was adjacent to the motorway, but no vehicles were travelling on that part of the M1 at the moment of the crash.