WHILE the exact cause of the horrific Air India crash is not yet known, speculation continues to swirl online.

The Boeing 787 Dreamliner, carrying 242 passengers, including 53 British nationals and 11 children, collided with a doctors’ hostel in western India on Thursday.

The plane was heading to London Gatwick when it crashed just moments after take-off.

Reports indicate that one of Flight AI171’s two “black boxes” has been found, which is expected to offer critical insights into the plane’s final moments from its departure to the crash.

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The black box will provide technical information on details like time, speed, altitude and heading.

The cockpit voice recorder could provide essential information, including pilot communication, engine noises, potential warnings, or any sounds from the equipment.

The crash killed at least 265 people – including those on board and locals on the ground.

As crash investigators begin to pour over that data, The Sun looks at six main theories as potential causes for India’s worst ever aviation disaster.

Bird strikes

A bird strike could have taken out both of the jet’s giant General Electric engines.

While a bird taking down something the size of a commercial airliner might sound fanciful, there are numerous examples.

Most famous was US Airways Flight 1549, which suffered double engine failure in 2009 after being hit by a flock of Canada geese shortly after taking off from New York’s LaGuardia Airport.

The plane, captained by Chesley “Sully” Sullenberger, was forced to make an emergency landing in the Hudson river – earning the tagline the “Miracle on the Hudson” since there were zero casualities.

Ahmedabad Airport is known to have a large bird population – with a study in 2018 concluding that the airport had “a high potential of bird-aircraft collision hazards”.

Captain C S Randhawa, who has flown a Boeing 777 for 15 years, said a bird strike was “the most probable” cause of the crash.

“Both Ahmedabad and Agra airports are full of birds. Incidents of aircraft being hit by birds keep happening on and off,” he told The New Indian Express.

Aviation safety consultant Captain Mohan Ranganathan told the same publication: “Bird hit appears to be the reason as of now.

“Ahmedabad airport has a history of a huge bird population. I flagged this issue 17 years ago and have written extensively about it too.”

Captain Ranganathan claims that the birds are drawn to the slaughterhouses near the airport.

He added: “The reason for such a huge presence is due to slaughterhouses in the vicinity of airports which should never have been allowed.

“They are never relocated by the authorities because they are owned by politicians or their relatives.”

In January 2021, an identical plane to the one involved in Thursday’s crash aborted a take-off in Mexico after birds flew into one of its engines.

Wing flap position

Aviation experts have suggested the position of the aircraft’s wing flaps could have played a role in the disaster.

Video evidence suggests the flaps were either fully retracted or on a very minimal setting, which would have provided very little lift. The flaps provide crucial extra lift at low speeds during take-offs and landings.

The aircraft’s landing gear also remained deployed throughout the crash sequence, which would have increased potentially fatal drag.

One theory is that the landing gear was stuck and pilots retracted the flaps to reduce drag or that the flaps were faulty and caused the plane to stall.

Aviation expert Terry Tozer, author of Confessions of an Airline Pilot, told the BBC: “It’s very hard to say from the video for sure.

“It doesn’t look as if the flaps are extended and that would be a perfectly obvious explanation for an aircraft not completing its take-off correctly.”

Marco Chan, a former pilot and a senior lecturer at Buckinghamshire New University, said: “That would point to potential human error if flaps aren’t set correctly, but the resolution of the video is too low to confirm that.”

Pilot error

The state-of-the-art Boeing 787-8 is highly automated, with human pilots making only key decisions – but human error cannot be ruled out.

Co-pilot Clive Kundar had more than 1,000 hours of flying experience and made the mayday call but Captain Sumeet Sabharwa at the helm had 8,000 hours – making him one of Air India’s most experienced pilots.

Sabharwa was also a trained instructor, meaning he had a deep understanding of flying protocol.

Estimates suggest the amount of runway utilised by the pilots was less than 2,000 metres – when a full plane on a hot day usually needs a run of 2,500 metres.

Additionally, since the wing flaps are also set by the pilots before takeoff, with multiple checklists and procedures in place to ensure that they are positioned correctly, that could also be another source of human error.

Heat

Planes get less lift on a hot day due to lower air density, and therefore they need to go faster to get as much lift as on a cooler day.

This is particularly important when an airliner is heavy with fuel, passengers and baggage, as the Air India flight was.

Flight AI171 took off in sweltering 40°C heat in the early afternoon sunshine.

The plane may have struggled to gain lift if it took off after a short runway take-off.

In his emergency mayday call, co-pilot Clive Kundar says “No thrust, losing power, unable to lift.”

Technical error

Catastrophic technical or engineering issues have not been ruled out.

The jet’s complex design mean it could take months for a design or engineering fault to be pinpointed.

The Dreamliner has a spotless safety record – this is the first time the model has crashed since its introduction in 2011.

However, airlines using the Boeing plane have reported numerous issues with the engines, including a mid-air dive on a LATAM Airlines flight last year.

During hearings in Washington last year, a former Boeing engineer turned whistleblower urged the aerospace giant to ground all Dreamliners.

The aircraft manufacturer rejected the claims and said it had full confidence in the 787.

However, the crash comes just weeks after Boeing agreed a £1.1bn payout with the US justice department to avoid prosecution over two crashes in 2018 and 2019 involving its 737 MAX model.

Overloading

The aircraft could also have been too heavy to take-off.

Danger of overloading could be increased – again –  by adverse weather conditions caused by extreme heat.

But the weight of aircraft is usually carefully checked ahead of take-off and the theory is thought unlikely.