The Kegworth air disaster occurred when a Boeing 737-400 crashed into the M1 highway embankment near Kegworth, Leicestershire, England, while trying to make an emergency landing at East Midlands Airport on 8 January 1989.
British Midland Flight 92 was on a scheduled flight from London Heathrow Airport to Belfast Airport, when a fan blade broke on the left engine, disrupting the air conditioner and filling the flight deck with smoke. Pilots believe that this indicates an error on the right machine, because the previous model of 737 ventilated the flight deck from the right, and they did not realize that 400 uses a different system. The flight crew mistakenly turned off a good machine, and pumped more fuel into a malfunctioning, burning machine. Of the 126 people in it, 47 died and 74 suffered serious injuries.
The investigation attributes a knife fracture to metal fatigue, caused by heavy vibrations in newly upgraded machines, which are only tested in the laboratory and not under representative flight conditions.
Video Kegworth air disaster
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Planes
The aircraft is Boeing 737-4Y0 operated by Midland UK, enrollment of G-OBME, on scheduled flights from London Heathrow Airport to Belfast International Airport, Northern Ireland, which has flown from Heathrow to Belfast and returned that day. The 737-400 is the latest design from Boeing, with the first unit to enter service less than four months earlier, in September 1988. G-OBME itself has been operating for 85 days, since October 15, 1988, and has collected 521 hours airframe. Earlier news reports from the BBC incorrectly reported that the aircraft involved was Douglas DC-9.
Cockpit crew
The flight was manned by 43-year-old Captain Kevin Hunt and 39-year-old First Officer David McClelland. Captain Hunt is a British Midland veteran pilot who has been with the airline since 1966 and has about 13,200 hours of flying experience. First Officer McClelland joined the British Midland in 1988 and has amassed about 3,300 hours of total flying. Among them, the pilot has nearly 1,000 hours in the Boeing 737 cockpit, only 76 of which are listed in the Boeing 737-400 series aircraft.
Maps Kegworth air disaster
Incident
After taking off from Heathrow at 7:52 pm, Flight BD 092 climbed through 28,300 feet to reach a 35,000 foot cruising altitude when the blade was released from the CFM International CFM56 fan (left) fan engine. While the pilot did not know the source of the problem, a sudden pounding sound was heard, accompanied by heavy vibrations. In addition, smoke enters the cabin through the ventilation system and a burning smell enters the aircraft. Some of the passengers sitting near the rear of the plane saw smoke and sparks coming from the left engine.
The flight was diverted to the nearest East Midlands Airport on the advice of Operation British Midland Airways.
After the initial knife fracture, Captain Kevin Hunt has released the autopilot plane. When Hunt asks David McClelland whose machine is damaged, McClelland replied: "This is what is left.... This is true". In the previous version of 737, the left AC packet, fed with a compressed air from the left engine (number 1), supplied air to the flight deck, while the right AC packet, fed from the right hand (number 2) supplied air to the cab. At 737-400 the air division is blurred; the left package feeds the flight deck but also feeds the rear cabin zone, while the right feeds the front cabin. The pilot has been used for older aircraft versions and was unaware that this plane (which was flown by Midland UK for 520 hours over a period of two months) was different. The captain later claimed that his perception of smoke as progressing from the cabin caused them to assume the error was in the right machine. The pilots choked back the right engine that served as a replacement for a non-functioning left engine. They had no way to visually inspect the machine from the cockpit, and the cabin crew - who did not hear the commander referring to the machine to the right at his cabin address - did not tell them that smoke and fire had been seen from the left engine.
When the pilots actually turn off the right machine, they can no longer smell the smoke, which makes them believe they have overcome the problem appropriately. Apparently, this is a coincidence: when the autothrottle is released to turn off the right engine, the fuel flow to the left engine is reduced, and the excess fuel that has burned in the jet exhaust disappears; Therefore, the ongoing damage is reduced, the smoke smell stops, and the vibration decreases, although it is still visible on the cockpit instrument.
During the final approach to the East Midlands Airport, more fuel is pumped into the damaged engine to maintain speed, causing it to stop fully operating and burning. The crew tried to revive the right engine by windmilling, using air flowing through the engine to turn the turbine blades and start the engine, but the plane now flew at 185 km/h (115 mph), too slow for this.. Just before crossing the M1 motorway at 20:24:43, the tail hit the ground and the aircraft flew back into the air and passed the highway, crashing into trees and lampposts before crashing a far embankment and breaking into three parts about 475 meters ( 519 yd ) short of the active paved surface and about 630 meters ( 689 yd ) from the threshold. Remarkably, no vehicles were traveling on the highway at the time of the accident.
Victim
Of the 118 passengers, 39 were killed in the accident and eight died later because of their injuries, with a total of 47 casualties. All eight crew members survived the crash. Of the 79 survivors, 74 suffered serious injuries and five suffered minor injuries. In addition, five firefighters also suffered minor injuries during the rescue operation. No one on the highway was injured, and all the vehicles around the disaster were not damaged. The first person to arrive at the scene to provide assistance was biker Graham Pearson. As a former Royal Marine, he helps passengers for more than three hours and then receives damage to post-traumatic stress disorder.
Cause
The investigation specifies that the fire warning light is not crosslinked (left/right).
Turned off the wrong machine
Captain Kevin Hunt believes the right-hand machine is damaged by the smell of smoke in the cabin because in the previous Boeing 737 variant, air for air conditioning is taken from the right-hand machine. Starting with the Boeing 737-400 variant, Boeing has redesigned the system to use the bleed air from both engines. Some cabin and passenger staff noticed that the left-hand engine had unburned fuel flows on the jet exhaust, but this information was not forwarded to the pilot because the cabin staff assumed they were aware that the left-hand engine was not working.
The smoke smell disappears when the autothrottle is released and the right engine dies due to fuel reduction to the damaged left engine as it returns to the manual throttle. In the event of malfunctions, pilots are trained to check all the yards and review all decisions, and Captain Hunt begins to do so. Although he was conducting a review, however, he was troubled by the transmission from East Midlands Airport telling him that he could descend further to 12,000 feet (3,700 m) in preparation for a diverted landing. He did not resume the review after the transmission ended, and instead started dropping. The vibration indicator is smaller than the previous version of the 737 in which the pilot has most of their experience.
Calls on two vibration gauges (one for each machine) are small and the LED needle rotates around the outer port of the dial as opposed to the inside of the dial as in the previous 737 series aircraft. The pilot did not receive simulator training on the new model, as there was no simulator for the 737-400 in the UK at that time. At that time, the vibration indicator is known to be unreliable (and usually ignored by the pilot), but unknown to the pilot, this is one of the first aircraft to have a very accurate vibration readings.
Engine damage
The engine analysis of the crash determined that the fan blade (LP Stage 1 compressor) of the CFM International CFM56 engine used on the 737-400 experienced an abnormal amount of vibration when operating at a high power setting above 10,000 feet (3,000 m). Because it is an upgrade to an existing machine, in-flight testing is not mandatory, and the machine is only tested in the laboratory. Upon this discovery, the remaining 99 Boeing 737-400s were then grounded and the engine modified. After the accident, it is now mandatory to test all newly designed and redesigned turbofan engines significantly under representative flight conditions.
This involuntary vibration creates excessive metal fatigue in the fan blades, and in G-OBME this causes one of the fan blades to break up. This damages the engine in a limited way and also disrupts its delicate balance, causing power reduction and increased vibration. Autothrottle attempted to compensate for this by increasing the flow of fuel to the engine. The damaged machine can not burn all the additional fuel, with most turning on the exhaust stream, creating a large fire trail behind the engine.
Aftermath
The official report on the disaster made 31 safety recommendations.
Evaluation of the injury suffered caused considerable improvements in aircraft safety and emergency instructions for passengers. This comes from a CAA funded research program and is conducted by teams from the University of Nottingham and Hawtal Whiting Structures (a consulting firm). Research between medical staff and engineers uses the analytical technique of "kinematics hosts" to assess the effectiveness of buffer positions. A new notice for operators revising the brace position was issued in October 1993.
The study of this accident led to the establishment of the International Council for Research into the Aircraft Crash Event (IBRACE) on 21 November 2016. IBRACE is a collaboration between experts in the field for the purpose of generating internationally agreed sets of evidence-based. impact position bracing for passengers and (finally) cabin crew in various seating configurations. This will be submitted to the International Civil Aviation Organization (ICAO) through the Cabin Safety Group (ICSG).
There are warnings for "those who died, those who were injured and those who took part in the rescue operation", at the village cemetery near Kegworth, along with landscaped gardens from the location of the accident.
Captain Hunt and First Officer McClelland were seriously injured in the accident, and then dismissed following criticisms of their actions in the AAIB report.
Hunt suffered injuries to his spine and legs during an accident. In April 1991, he told BBC documentary: "We are an easy choice - a cheap option if you want.We make mistakes - we both make mistakes - but the question we want to answer is why we made that mistake." BM then paid McClelland is an out-of-court settlement for unfair dismissal.
Alan Webb, Chief Fire Officer at East Midlands Airport, was awarded the MBE on the New Year's Year list for his team's coordination in rescue efforts after the accident.
Graham Pearson, a passing rider who assisted Kegworth's victims at the crash site for three hours, sued the airline for post-traumatic stress disorder and was awarded Ã, Â £ 57,000 in damages in 1998 (Ã, Â £ 92,000 today).
Media
The accident was featured in a 1991 documentary Taking Freedom named 'Fatal Error'
Flight 092 is also featured in an episode of Seconds From Disaster , called "Crash Aircraft Motorway".
It was also featured in the Discovery Discovery 2011 documentary Aircrash Confidential .
In 2014, the incident was featured in the episode "Choosing a Side" from the documentary series Mayday .
See also
- List of accidents and incidents involving commercial aircraft
- TransAsia Airways Flight 235, another incident when the pilot turned off the wrong machine
References
- Notes
- References
External links
- the BBC's 10 year warning page about an accident
- The BBC 'On This Day' page of an accident
- Pre-collision images and airplane crashes from Airliners.net
Source of the article : Wikipedia
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