Kegworth air disaster
On a cold January night in 1989, British Midland Flight 092 descended towards East Midlands Airport, its pilots believing they had contained a catastrophic engine failure. But a crucial misidentification, compounded by subtle design changes, turned a manageable emergency into a horrific tragedy. This disaster would expose critical flaws in aircraft design certification and pilot training, forever changing aviation safety protocols. A critical misdiagnosis by the pilots led to the shutdown of a functioning engine instead of the failing one. Subtle design changes in newer aircraft models, without adequate pilot training, can have devastating consequences. The accident highlighted a severe flaw in engine certification, leading to mandatory in-flight testing for new designs.
AI Summary
On a cold January night in 1989, British Midland Flight 092 descended towards East Midlands Airport, its pilots believing they had contained a catastrophic engine failure. But a crucial misidentification, compounded by subtle design changes, turned a manageable emergency into a horrific tragedy. This disaster would expose critical flaws in aircraft design certification and pilot training, forever changing aviation safety protocols.
- A critical misdiagnosis by the pilots led to the shutdown of a functioning engine instead of the failing one.
- Subtle design changes in newer aircraft models, without adequate pilot training, can have devastating consequences.
- The accident highlighted a severe flaw in engine certification, leading to mandatory in-flight testing for new designs.
The Kegworth Air Disaster
It was January 8, 1989. British Midland Airways Flight 092, a brand-new Boeing 737-400, was on a routine flight from London Heathrow to Belfast. But as it climbed through the night sky, a catastrophic series of events unfolded, culminating in a crash that would claim 47 lives and injure many more.
A Modern Marvel, Untested Flaws
The aircraft, G-OBME, was one of Boeing's latest—a 737-400, an upgraded version of a proven design. It had only been in service for a mere four months, accumulating just over 500 flight hours. Unknown to anyone at the time, its advanced CFM International CFM56 turbofan engines harbored a deadly secret.
The Cockpit Crew
At the controls were Captain Kevin Hunt, 43, with over 13,000 hours of flying experience, and First Officer David McClelland, 39, with 3,300 hours. While both were seasoned pilots, their experience on this specific 737-400 model was minimal—just 23 hours for Captain Hunt and 53 hours for First Officer McClelland.
The Flight and the Fatal Error
Around 8 PM, as the plane ascended through 28,300 feet, a sudden, violent shuddering tore through the cabin. A loud pounding noise filled the cockpit, followed by smoke seeping through the air conditioning vents. Near the rear, passengers reported seeing sparks and flames erupting from the left engine.
In the cockpit, Captain Hunt instinctively took control. He asked First Officer McClelland which engine was failing, and McClelland replied, "It's the right one." This critical misidentification was based on an outdated assumption: in older 737 models, cabin air was drawn exclusively from the right engine, so smoke in the cabin typically meant a problem with that engine. The 737-400, however, used a bleed air system drawing from both engines, a change the pilots were not fully aware of.
Believing they had identified the problem, the pilots retarded the thrust lever for the right engine, intending to shut it down. To their relief, the smoke and vibrations quickly subsided. This deceptive calm cemented their belief that they had correctly diagnosed and addressed the emergency.
What they didn't know was that reducing power to the right engine also momentarily reduced fuel flow to the damaged left engine, lessening the flames and vibrations. Critical instruments, like the vibration gauges, which could have shown the left engine was still the problem, were small and unfamiliar. Moreover, no cabin crew passed on their observations of flames from the left engine, assuming the pilots were already aware.
The Descent and Second Failure
The flight was diverted to nearby East Midlands Airport. As they began their final approach, the pilots needed to increase power to maintain speed and altitude. They increased thrust on the remaining, and unbeknownst to them, damaged left engine. This was a fatal decision.
The surge of power dislodged the tip of the already fractured fan blade in the left engine. It was sucked into the engine's core, causing catastrophic damage and igniting a fire. The now fully compromised engine sputtered and failed completely. The aircraft was left with no effective thrust.
The Final Moments and Impact
The cockpit was flooded with warnings—the ground proximity warning system blared "glideslope" alerts, and the stick shaker activated, signaling an imminent stall. Captain Hunt frantically announced, "Prepare for crash landing!"
Just seconds later, at 8:24 PM, the aircraft clipped trees, struck an embankment between the M1 motorway and a local road, and broke into three sections. Miraculously, no vehicles on the motorway were hit. The crash site was only about 500 yards short of the runway.
The Human Cost
Of the 126 people on board, 47 perished, and 74 sustained serious injuries. All eight crew members survived, albeit with severe trauma. The rapid response of emergency services, aided by a passing motorist and a troop of SAS soldiers, was crucial in saving many lives.
Unraveling the Causes: A Chain of Events
The investigation revealed a confluence of factors leading to the tragedy. The pilots' initial misdiagnosis stemmed from their experience with older 737s, where cabin bleed air came solely from the right engine. They simply weren't aware that the 737-400's redesigned system used both engines.
The deceptive clearing of smoke and vibration after shutting down the wrong engine cemented their error. An interruption from air traffic control during a crucial post-shutdown checklist meant the pilots never completed their full review, missing vital instrument readings that would have pointed to the left engine.
Furthermore, the cockpit's vibration gauges were smaller and displayed information differently than those on earlier 737 models. Pilots had received no simulator training on the 737-400, as no such simulator existed in the UK at the time, leaving them unprepared for these subtle but critical differences.
The ultimate root cause lay deep within the left engine itself. Analysis showed that the fan blades of the upgraded CFM56 engine were susceptible to aerodynamic flutter at high power settings above 10,000 feet. This constant vibration caused undetected metal fatigue in one of the blades.
Crucially, because the CFM56 was considered an 'upgrade' of an existing engine, it was not subjected to mandatory in-flight testing under representative conditions—only ground tests. This oversight meant the flutter phenomenon was never discovered during certification.
The Enduring Legacy
The Kegworth disaster prompted 31 safety recommendations. All 99 Boeing 737-400s then in service were grounded, and their engines were modified. In-flight testing for all new or significantly redesigned turbofan engines became mandatory, ensuring such a flaw would never go unnoticed again.
The crash also led to extensive research into aircraft safety and passenger injury evaluation. Experts used occupant kinematics to analyze the effectiveness of the brace position, resulting in improved emergency instructions and the formation of the International Board for Research into Aircraft Crash Events (IBRAICE).
Captain Hunt and First Officer McClelland, both severely injured, were dismissed from British Midland, though McClelland later received an out-of-court settlement for unfair dismissal. Their poignant question, "Why we made those mistakes," underscored the complex chain of events, from design and certification to training and human factors, that contributed to the disaster.
Today, a memorial stands in Kegworth village cemetery, honoring those who died, those who were injured, and those who bravely participated in the rescue. The Kegworth air disaster remains a stark reminder of the continuous effort required to advance aviation safety.
Article
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.
Aircraft involved and crew
Aircraft
The aircraft was a British Midland-operated Boeing 737-4Y0, registration G-OBME, on a scheduled flight from London Heathrow Airport to Belfast International Airport, Northern Ireland, having already flown from Heathrow to Belfast and back that day. The 737-400 was the newest design from Boeing, with the first unit entering service less than four months earlier, in September 1988. G-OBME had accumulated 521 airframe hours. The aircraft was powered by two CFM International CFM56 turbofan engines.
Cockpit crew
The flight was crewed by 43-year-old Captain Kevin Hunt and 39-year-old First Officer David McClelland. Hunt had been with British Midland since 1966 and had about 13,200 hours of flying experience. First Officer McClelland joined the airline in 1988 and had about 3,300 total flight hours. Between them, the pilots had close to 1,000 hours in the Boeing 737 cockpit (Hunt had 763 hours, and McClelland had 192 hours), but only 76 of these had been in Boeing 737-400 series aircraft (Hunt 23 hours and McClelland 53 hours).
Accident
Kegworth air disaster
Photograph taken in May 2006, showing the location of the disaster
After taking off from Heathrow at 19:52, Flight BD 092 was climbing through 28,300 feet (8,600 m) to reach its cruising altitude of 35,000 feet (11,000 m) 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.
Wreckage of G-OBME
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 (115 kn; 132 mph) 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 metres (519 yd) short of the active runway's paved surface and about 630 metres (690 yd) 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.
Casualties
Kegworth air disaster
Of the 118 passengers on board, 39 were killed outright in the crash and 8 died later of their injuries, for a total of 47 fatalities. All eight crew members survived the accident. Of the 79 survivors, 74 suffered serious injuries and 5 suffered minor injuries. In addition, five firefighters also suffered minor injuries during the rescue operation. No-one on the motorway was injured, and all vehicles in the vicinity of the disaster were undamaged. The first person to arrive at the scene and render aid was a motorist who helped passengers for over three hours and subsequently received damages for post-traumatic stress disorder. Aid was also given by a troop of eight SAS soldiers - four of whom were regimentally qualified paramedics - who happened to be driving a truck on the M1 a short distance away from the crash site.
Causes
Kegworth air disaster
The investigation established that the wiring associated with the fire warning lights was properly connected. Initially there was a concern that the sensors in the engines and the warning lights on the flight deck may have been cross-wired.
Shutting down of wrong engine
The smell of smoke in the cabin led Captain Hunt to believe that the right engine was malfunctioning, because in earlier Boeing 737 variants, bleed air for cabin air conditioning came from the right engine. Starting with the Boeing 737-400 variant, Boeing had redesigned the system to use bleed air from both engines. Several cabin staff and passengers noticed that the left engine had a stream of unburnt fuel igniting in the jet exhaust, but this information was not passed to the pilots because cabin staff assumed they were aware that the left engine was malfunctioning.
The smell of smoke disappeared when the autothrottle was disengaged and the right engine shut down, because the fuel flow to the damaged left engine decreased as it reverted to manual throttle. In the event of a malfunction, pilots were trained to check all meters and review all decisions, and Captain Hunt proceeded to do so. Whilst he was conducting the review, however, he was interrupted by a transmission from East Midlands Airport informing him he could descend further to 12,000 feet (3,700 m) in preparation for the diverted landing. He did not resume the review after the transmission ended, and instead commenced descent.
The dials on the two vibration gauges (one for each engine) were smaller than on the previous versions of the 737 in which the pilots had the majority of their experience and the LED needle went around the outside of the dial as opposed to the inside. The pilots had received no simulator training on the new model, as no simulator for the 737-400 existed in the UK at that time. At the time, vibration indicators were known for being unreliable (and normally ignored by pilots), but unknown to the pilots, this was one of the first aircraft to have a very accurate vibration readout, although it was still permitted to fly with one gauge unserviceable under Boeing's Minimum Equipment List.
Engine malfunction
Analysis of the engine from the crash determined that the fan blades (LP stage 1 compressor) of the uprated CFM International CFM56 engine used on the 737-400 were subject to abnormal amounts of vibration when operating at high power settings above 10,000 feet (3,000 m). As it was an upgrade to an existing engine, in-flight testing was not mandatory, and the engine had only been tested in the laboratory. Upon this discovery, the remaining 99 Boeing 737-400s then in service were grounded and the engines modified. Following the crash, testing all newly designed and significantly redesigned turbofan engines under representative flight conditions is now mandatory.
This unnoticed vibration created excessive metal fatigue in the fan blades, and on G-OBME this caused one of the fan blades to break off. 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. The damaged engine was unable to burn all the additional fuel, with much of it igniting in the exhaust flow, creating a large trail of flame behind the engine.
Aftermath
Kegworth air disaster
Memorial scroll in St Anne's Cathedral, Belfast
The official report into the disaster made 31 safety recommendations. Evaluation of the injuries sustained led to considerable improvements in aircraft safety and emergency instructions for passengers. These were derived from a research programme funded by the CAA and carried out by teams from the University of Nottingham and Hawtal Whiting Structures (an engineering consultancy company). The study between medical staff and engineers used analytical "occupant kinematics" techniques to assess the effectiveness of the brace position. A new notice to operators revising the brace position was issued in October 1993.
The research into this accident led to the formation on 21 November 2016 of the International Board for Research into Aircraft Crash Events, which is a joint co-operation between experts in the field for the purpose of producing an internationally agreed-upon, evidence-based set of impact bracing positions for passengers and (eventually) cabin crew members in a variety of seating configurations. These will be submitted to the International Civil Aviation Organization through its Cabin Safety Group.
Memorial garden at Kegworth cemetery
A memorial was built in the village cemetery in nearby Kegworth to "those who died, those who were injured and those who took part in the rescue operation", together with a garden made using soil from the crash site.
Captain Hunt and First Officer McClelland, both seriously injured in the crash, were dismissed following the criticisms of their actions in the Air Accidents Investigation Branch report. Hunt suffered injuries to his spine and legs in the crash. In April 1991, he told a BBC documentary, "We were the easy option – the cheap option if you wish. We made a mistake – we both made mistakes – but the question we would like answered is why we made those mistakes." British Midland later paid McClelland an out-of-court settlement for unfair dismissal.
Alan Webb, the chief fire officer at East Midlands Airport, was made an MBE in the 1990 New Year Honours list for the co-ordination of his team in the rescue efforts that followed the crash. Graham Pearson, a passing motorist who assisted Kegworth survivors at the crash site for three hours, sued the airline for post-traumatic stress disorder and was awarded £57,000 in damages in 1998 (equivalent to £106,000 in 2024).
Media
Kegworth air disaster
The crash was featured in a 1991 documentary, an episode of the series Taking Liberties named "Fatal Error". it was also featured in an edition of ITV's The Cook Report in 1993 entitled "Don't Shoot the Pilot", ITV aired a documentary in 1999 of the Kegworth crash. Flight 092 was also featured in an episode of Seconds From Disaster called "Motorway Plane Crash".
It was also featured in the 2011 Discovery Channel documentary Aircrash Confidential.
In 2015, the incident was featured in the episode "Choosing Sides" or "M1 Plane Crash" of the documentary television series Mayday, or Air Crash Investigation, as it is known in the UK.
In 2024, the incident was also featured on the "M1 Plane Crash" episode of Terror at 30,000 Feet on Channel 5.
Kegworth: Flight to Disaster was broadcast on BBC Northern Ireland on 8 January 2025, the 36th anniversary of the accident.