On June 12, 2025, Air India Flight 171 erupted into a ball of flames, crashing back down to the ground less than a minute after take-off. All but one of the 242 people on board were killed, as well as 19 people on the ground. A year on, how much do we know about what caused this tragedy?
Taking off from Ahmedabad airport, the flight was bound for London. The pilots were Captain Sumeet Sabharwal and First Officer Clive Kunder.
Footage from airport CCTV and a video posted to social media showed the Boeing 787-8 lifting off the runaway like any other flight.
It climbed to a height of around 625 feet (190m), before appearing to lose power and descending out of the sky.
For a second, it disappeared from the footage behind buildings and trees, before an enormous ball of flame and black smoke erupted from the ground.
We know what happened from the outside. What happened inside the plane, besides a few key details, remains shrouded in mystery.
What the flight recordings tell us
Investigators from India’s Aircraft Accident Investigation Bureau managed to recover a flight data recorder from the scene, colloquially known as a black box.
This recorded a "combined data stream of digital flight data and cockpit voice information" – the entire event was captured.
No transcript from the voice recording has been made available.
Instead, two sentences based on recorder data in a preliminary report released by the AAIB around a month after the disaster have generated mass speculation.
Shortly after take-off, the report said, fuel cut-off switches for both engines went from the RUN to CUTOFF positions within a second of each other.
The loss of fuel to both engines would’ve caused a rapid loss of thrust.
“In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff,” the report said. “The other pilot responded that he did not do so.”
Moments later, the switches flipped back to the RUN positions.
By then, it was too late.
Pilot's father fighting for son's name
Captain Sumeet Sabharwal has been at the centre of mass speculation, with many suggesting he deliberately condemned himself and those on board to death.
The Wall Street Journal reported it was the captain who had cut the fuel to the engines, according to sources familiar with the situation.
Leading aviation safety expert in India Captain Mohan Ranganathan told The Telegraph in July of last year he had “heard from several Air India pilots who told me he had some depression and mental health issues”.
“He had taken time off from flying in the last three to four years. He had taken medical leave for that.”
The AAIB condemned the speculation, urging the media to “refrain from spreading premature narratives that risk undermining the integrity of the investigative process”.
Speaking to BBC News India in an interview released on Friday, Sabharwal’s father Pushkar Raj said he had to protect his son’s reputation.
“You see, every time an accident takes place, the pilot is blamed. Why? It's the simplest way to close the chapter. He is no more and cannot defend himself,” he said.
He said his son had been planning to retire soon to spend more time with him.
He recalled the day of the tragedy.
“That day, he was positioned for a flight from Ahmedabad. He told me, I'm boarding the aircraft and I'll call you from Gatwick. And a short while later, everything happened.
“I can say it is a loss, an unbearable loss.”
Alternative theories
Indian journalist Rachel Chitra has reported extensively on the disaster and subsequent investigation.
In an article for Indian magazine The Caravan published at the beginning of this month, she said several aviation engineers she spoke to describe the preliminary report as “shoddy” and missing “crucial” details.
She has presented an alternative theory, developed by speaking to “nearly 30 pilots, engineers and analysts about the evidence presented and other documents I had received from whistleblowers at Boeing, Air India and the AAIB”.
According to Airplane Health Management records, she said, six “NO-GO” fault codes existed on the plane minutes before take-off. These codes usually result in take-off clearance being rescinded.
“The codes, according to several engineers I spoke to, suggested that the plane suffered a massive electrical failure shortly into take-off,” Chitra wrote.
A senior Air India engineer told her the faults caused the flight computers to reboot and briefly enter “ground mode”, causing the fuel cut-off, she said.
“The evidence around this pokes major holes in the theory that the captain cut fuel to the engine.”
Another source of doubt has been the timing of an emergency power system’s deployment – the Ram Air Turbine (RAT).
The RAT is a small wind turbine that deploys into the airstream during a total loss of power.
CCTV footage showed the RAT had deployed immediately after take-off, providing hydraulic power within five seconds of the fuel switch cut-off.
The BBC has reported on simulator tests that “appear to demonstrate that it would actually need 14-18 seconds”.
“This would imply that it had actually deployed far earlier, potentially while the aircraft was on the ground, and well before the fuel was cut off,” the BBC reported.
A lawyer for victims’ families told the BBC these findings raised important questions and cast doubt over the narrative that Sabharwal deliberately brought the plane down.
In February, the grounding of another Boeing 787-8 attracted attention as a pilot’s report identified an issue with one of the fuel control switches.
The report said the left fuel control switch “slips from ‘RUN’ to ‘CUTOFF’ when pushed slightly and does not lock positively in its selected position", an Indian Ministry of Civil Aviation release stated.
After an investigation, India’s aviation regulator said it had found no defect in the fuel control switch.
When will we know?
The sole survivor of the crash, Vishwash Kumar Ramesh, has been one of many demanding answers.
“More than anything, people need honesty, transparency and answers. Nothing will ever change what happened, but families deserve clarity,” he told the UK’s Press Association.
The foreword of the preliminary report stated that: “The sole objective of the investigation of an Accident/Incident shall be the prevention of accidents and incidents and not to apportion blame or liability.”
India’s aviation minister said in May the investigation was in its “last stage” and would be mostly finished by the June 12 anniversary.
According to International Civil Aviation Organization rules, a final report should be published within 12 months if possible.
If this wasn’t possible an interim report had to be published on the anniversary date.
At the time of writing, this has yet to be done.
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