Thirty years after a British Midlands plane crashed into the M1, the Kegworth air disaster is remembered for how it shaped flight safety.
Shortly after leaving Heathrow for Belfast, a fan blade broke in Flight BD 092's left engine, causing a pounding noise, vibrations and smoke.
Confused about which engine had failed, Captain Kevin Hunt and co-pilot David McClelland mistakenly shut down the one still working.
When more fuel was pumped into the damaged engine, it burst into flames.
The flight had been diverted to East Midlands Airport but did not make it to the runway, crashing into the embankment of the northbound carriageway of the M1 and killing 47 of the 126 people on board. Seventy-four people were seriously injured.
Following the disaster, scientists examined the final moments of the flight and looked at what went wrong.
Here, we look at some of the lessons that have been learned and how Kegworth changed air safety.
- What did the salvage teams find?
RAF teams who had previously worked on the Lockerbie disaster salvaged materials from the site to piece together the tragedy.
For the first time experts from the University of Nottingham and Hawtal Whiting Structures used computer simulations to pinpoint how passengers prepared for impact, looking extensively at their seat number and injuries.
They found that those passengers who sat upright were more likely to sustain fractures and injuries.
But what surprised researchers the most was the extent of the injuries suffered by survivors who had adopted the 'brace-for-impact’ position.
Of those who survived, many were recorded to have pelvic and lower limb injures which led to a much-needed revision of the emergency landing procedure.
- Modified brace position
Extensive investigations were carried out into how each passenger was positioned when the plane crashed and the injuries they sustained.
Given the injuries suffered by those adopting what was then the standard brace position, it was decided that officials should develop a new, safer position that would do a better job of protecting passengers in the event of a crash.
This lead to the development of a new brace position that has been adopted by airlines around the world.
Passengers are now advised to place their feet and knees together with their feet flat against the floor and further back than the knees and place their head on the seat in front.
- Better communication between the cockpit and the cabin
The pilots of the British Midland Boeing 737 mistakenly shut down the correctly-working right-hand engine after loud bangs were heard coming from the left-hand engine.
When the commander broadcast to the cabin that this action had been taken, the passengers and cabin crew did not alert him to the error despite some of them seeing the original malfunction to the left-hand engine.
A report by the Air Accidents Investigation Branch found that passengers would be unlikely to think they could contribute to a pilot's understanding of a situation, while cabin crew would be concerned that any intrusion into the flight deck during busy periods could be a distraction.
In the aftermath of the crash, airlines across the world began giving Cockpit Resource Management training to their staff.
This teaches that more information should be shared between pilots in the cockpit, while cabin crew should have the confidence to challenge flight crew if they believe a mistake has been made.
- Emergency situation provisions improved
As well as the brace position, the disaster prompted the airline industry to look at all aspects of their emergency procedures to ensure the best chance of survival for passengers.
For example, aircraft manufacturers must now be able to demonstrate that a full plane can be evacuated through half of the emergency exits in less than 90 seconds.
Writing about developments across the industry as a result of Kegworth, Martin Brennan, the vice-chair of the Institution of Occupational Safety and Health's Aviation and Aerospace Group, said: "The standardisation of cabin crew emergency and evacuation procedures and safety demonstrations across the industry, and the inclusion of pictorial safety briefing cards at each passenger seat, have all helped to sensitise the travelling public to the procedures which will enable them to efficiently and effectively evacuate an aircraft in the event of an emergency."
- How ITN reported on the disaster in 1989: