What could have caused Air India plane to crash in 30 seconds?

What precisely happened to Flight AI171 betwixt Ahmedabad and London Gatwick connected Thursday day volition lone beryllium revealed by a elaborate investigation, but the moments aft take-off tin beryllium the astir challenging successful aviation.

Indian investigators volition beryllium joined by experts from the US and UK successful the coming days, arsenic authorities effort to found what caused the Boeing 787-8 Dreamliner to clang soon aft take-off conscionable 1.5km (0.9 miles) from the runway astatine Sardar Vallabhbhai Patel International Airport.

It marks the archetypal clip a 787-8 Dreamliner has suffered a fatal clang since it entered commercialized work successful 2011. Thursday's catastrophe killed 241 radical onboard and much connected the ground.

The BBC has spoken to aviation experts arsenic good arsenic pilots based successful India - immoderate of whom spoke connected the information of anonymity - who regularly alert 787-8s retired of India's planetary airports to find retired what factors mightiness person caused the level to slam into residential buildings successful the bosom of Ahmedabad conscionable moments into its flight.

The 787-8 Dreamliner was flown by Captain Sumeet Sabharwal and his co-pilot Clive Kundar. The 2 were highly experienced, with much than 9,000 combined flying hours. Mr Sabharwal having earned implicit 22-years expertise arsenic a commercialized hose pilot.

The level was carrying 242 radical arsenic it taxied on the runway astatine Ahmedabad International Airport connected Thursday afternoon. The pitchy took disconnected astatine 13:39 section clip (08:09 GMT), relation Air India said.

India's Home Affairs Minister Amit Shah said the level was carrying 100 tonnes of substance - practically a afloat load - arsenic it climbed retired of Ahmedabad.

Almost instantly aft take-off the cockpit gave a mayday call, India's aviation regulator said. No effect was fixed by the craft aft that. It's unclear what prompted the mayday call, but the flight's sole subsister has told Indian media that helium heard a large bang arsenic the level struggled to summation altitude.

Footage authenticated by BBC Verify past showed the level flying debased implicit what appears to beryllium a residential neighbourhood. The last transmitted information showed the level reached astatine a tallness of 625ft (109m). It proceeds to descend and becomes obscured by trees and buildings, earlier a ample detonation appears connected the horizon.

"There would person been nary clip for him to respond if helium mislaid some engines," 1 aviator said. CCTV footage viewed by BBC Verify showed that the level was airborne for 30 seconds.

The level crashed successful a residential area, with images showing lodging blocks heavy damaged successful a densely built country which included hospitals and authoritative buildings.

It is astir intolerable to definitively found what caused the catastrophe based connected videos of the plane's little flight.

In the coming days a analyzable probe involving the plane's achromatic container - which records formation information - and an introspection of debris volition commence. But videos that person emerged amusement the level struggling to assistance disconnected the ground, seemingly amid a deficiency of thrust oregon power.

One origin that has been speculated connected by immoderate experts is the anticipation of an highly uncommon treble motor failure. Questions person been raised arsenic to whether the level had its Ram Air Turbine (RAT) deployed, an exigency back-up turbine which kicks successful erstwhile main engines neglect to make powerfulness for indispensable systems.

Double motor failures are astir unheard of, with the astir notable illustration being the 2009 "Miracle connected the Hudson", erstwhile a US Airways Airbus A320 mislaid some engines to a vertebrate onslaught moments aft take-off from New York's LaGuardia Airport, but glided to safety.

One elder aviator told the BBC that dual motor nonaccomplishment could besides effect from substance contamination oregon clogging. Aircraft engines trust connected a precise substance metering strategy - if that strategy gets blocked, it tin pb to substance starvation and motor shutdown.

Marco Chan, an ex-pilot, told BBC Verify that determination isn't immoderate grounds to suggest a treble motor nonaccomplishment based connected the disposable footage.

Mohan Ranganathan, an aviation expert, told the BBC that a treble motor nonaccomplishment would beryllium "a very, precise uncommon incident".

Engine shaper GE Aerospace said it was sending a squad to India to assistance with the investigation, portion Boeing said it was offering its afloat enactment to the airline.

Another anticipation raised by immoderate experts successful India is simply a vertebrate strike.

They hap erstwhile a level collides with a vertebrate and tin beryllium highly unsafe for aircraft. In superior cases, engines tin suffer powerfulness if they suck successful a bird, arsenic happened successful South Korea's Jeju Air disaster which killed 179 radical past year.

Experts and pilots acquainted with Ahmedabad airdrome person told the BBC that it is "notorious for birds".

"They are ever around," says Mr Ranganathan, echoing what astatine slightest 3 Indian pilots who person flown successful and retired of the airdrome told the BBC .

Gujarat state, wherever Ahmedabad is located, reported 462 vertebrate onslaught incidents implicit 5 years, with astir occurring astatine Ahmedabad airport, according to Civil Aviation Ministry information tabled successful Parliament successful December 2023.

A Times of India study successful September 2023 cited Airport Authority information noting 38 vertebrate strikes successful 2022–23 successful Ahmedabad, a 35% emergence implicit erstwhile 12 months.

In the 2009 case, a flock of seagulls was ingested astatine 2,700ft – much than 4 times higher than the Air India flight. In this lawsuit the Indian pilots had neither the altitude nor the clip to manoeuvre.

However, a elder aviator said that a vertebrate deed is seldom catastrophic "unless it affects some engines".

Three experts who spoke to BBC Verify suggested that the catastrophe whitethorn person occurred arsenic the aircraft's flaps were not extended during take-off - though different pilots and analysts person challenged this.

Flaps play a captious relation during take-off, helping an craft make maximum assistance astatine little speeds.

If they're not decently extended, a afloat loaded pitchy - carrying passengers, dense substance for a long-haul flight, and battling blistery conditions - volition conflict to assistance off.

In Ahmedabad, wherever temperatures neared 40°C (104F) connected Thursday, the thinner aerial would person demanded higher flap settings and greater motor thrust, 1 aviator told the BBC. In specified conditions, adjacent a tiny configuration mistake tin person catastrophic consequences.

CCTV footage which emerged precocious connected Thursday day showed the level taking disconnected from Ahmedabad, struggling to execute altitude, and past dilatory descending earlier crashing.

But a take-off rotation with retracted flaps would trigger warnings from the 787's take-off Configuration Warning System, alerting the formation unit to an unsafe configuration, according to 1 aviator the BBC spoke to.

Ex-pilot Mr Chan told BBC Verify that the footage that has emerged truthful acold is excessively distorted to found for definite whether the flaps were extended, but said that specified an mistake would beryllium "highly unusual".

"The flaps are acceptable by pilots themselves, earlier instrumentality off, and determination are respective checklists and procedures to verify the setting," Mr Chan said. "That would constituent to imaginable quality mistake if flaps aren't acceptable correctly."

Additional reporting by Jake Horton