New Delhi, India – Just moments before a fatal Air India crash on June 12, the Boeing 787 Dreamliner’s fuel-control switches in the cockpit mysteriously moved from the “run” to the “cutoff” position, an early investigation into the disaster has revealed.

Flipping to cutoff almost immediately cuts the engines. The investigation’s report, issued by India’s Aircraft Accident Investigation Bureau (AAIB) early on Saturday, found that both engines shut down within the space of one second, leading to immediate loss of altitude.

The report does not conclude any reason for the switches moving or apportion blame for the crash of Air India’s Flight 171, which had been bound for London’s Gatwick Airport.

Rather, the new details emerging from the report, including voice recordings from the cockpit, appear to have compounded the mystery about what caused the crash.

This is what the report has found and what we know about the final minute before the plane crashed.

What happened on June 12?

At 13:38 [08:08 GMT] on the afternoon of June 12, the Dreamliner departed Ahmedabad for London Gatwick with 230 passengers, 10 cabin crew and 2 pilots on board.

Less than 40 seconds later, the aircraft lost both engines during its initial climb.

In the first such incident for a 787 Dreamliner, the plane crashed into the BJ Medical College hostel and adjoining structures in a densely populated suburb of the city, just under a nautical mile (equivalent to about 1.85km) from the runway.

The aircraft broke apart on impact, igniting a fire that destroyed parts of five buildings. All but one of the people on board the plane were killed. The sole survivor was Vishwaskumar Ramesh, a 40-year-old British national of Indian origin.

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Some 19 people on the ground were also killed and 67 were injured.

What has the investigation revealed?

The AAIB, an office under India’s Ministry of Civil Aviation, is leading the probe into the world’s deadliest aviation accident in a decade. The probe is also joined by experts from Boeing and participants from the United States and United Kingdom.

According to the preliminary report, the aircraft was deemed airworthy, with its Airworthiness Review Certificate valid until May 2026. Routine maintenance had been carried out, and no dangerous goods were on board.

However, investigators noted a previous US Federal Aviation Administration (FAA) advisory from December 2018 regarding a potential flaw in the aircraft’s fuel-control switch system – highlighting the potential disengagement of the locking feature.

The report on the Air India crash noted that this advisory had been prompted by reports from operators of Boeing 737 aircraft, highlighting that fuel-control switches had been found to have been installed with their locking mechanisms disengaged.

Air India told the investigators that no inspection had been made in response to this SAIB, since compliance was not mandatory.

The report noted that the throttle control module on the aircraft had been replaced in 2019 and again in 2023. However, these replacements were not related to the fuel-control switch, and no defects concerning the switch have been reported since 2023, the report highlighted.

Key systems such as the Ram Air Turbine (RAT) and Auxiliary Power Unit (APU) were engaged and attempted automatic recovery, but only partial engine relight was achieved before the aircraft crashed.

What does the audio recording from the cockpit reveal?

Shortly after takeoff, both engines shut down almost simultaneously, as the fuel control switches inexplicably moved from “run” to “cutoff”.

Cockpit voice recordings captured one pilot questioning the other, “Why did you cut off?”

The other pilot replied that he had not done so.

The pilots quickly attempted to recover control: the fuel switches were returned to “run”; the Ram Air Turbine (RAT) was deployed; and the Auxiliary Power Unit (APU) auto-started.

According to the report, Engine 1 began relighting, but Engine 2 failed to regain thrust. Just seconds before impact, a panicked “MAYDAY MAYDAY MAYDAY” call was transmitted.

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What did air traffic control observe?

The Air Traffic Control Officer at Ahmedabad received no response at all following the Mayday call sign but observed the aircraft crashing outside the airport boundary.

CCTV footage from the airport showed the aircraft’s Ram Air Turbine (RAT) being deployed during the initial climb immediately after lift-off. The aircraft then started to lose altitude before crossing the airport perimeter wall.

The report has not determined whether the fuel-switch shutdown was mechanical or accidental. The investigators have also not “speaker-stamped” the voice recording – identified who is speaking – from the cockpit yet.

Who were the pilots?

Captain Sumeet Sabharwal, the 56-year-old pilot-in-command (PIC), had extensive experience with 15,638 total flying hours, including 8,596 hours on the Boeing 787, of which 8,260 hours were as PIC.

The co-pilot, or first officer, was Clive Kunder. The 32-year-old had accumulated 3,403 flying hours, including 1,128 hours on the B787, all as co-pilot. His endorsements included C172 and PA-34 as PIC and A320 and B787 as co-pilot.

On the day of the accident, Kunder was the pilot flying the Dreamliner while Sabharwal acted as the pilot monitoring, responsible for supporting the flight through communication with air traffic control and system monitoring.

This is a second-by-second timeline of Flight 171’s last moments:

08:07:33 [GMT]: Cleared for takeoff from Ahmedabad’s runway 23.

08:07:37: Aircraft begins takeoff roll.

08:08:33: Aircraft reaches V1 (153 knots).

08:08:35: Aircraft achieves Vr (155 knots) for rotation.

08:08:39: Lift-off registered.

08:08:42: Aircraft peaks at its maximum recorded speed of 180 knots; both engine-fuel switches abruptly transition to “cutoff”.

08:08:47: Engines lose power; RAT deploys to provide emergency hydraulics.

08:08:52: Engine 1 fuel switch is returned to “run”.

08:08:54: APU inlet door begins to open (auto-start initiates).

08:08:56: Engine 2 fuel switch also moved to “run”.

08:09:05: Pilot transmits “MAYDAY MAYDAY MAYDAY”.

08:09:11: Final data recorded; aircraft hits the ground.

According to Saturday’s report, at this stage of the investigation, there is no need for airlines or engine makers to take any action regarding the Boeing 787-8 planes or GE GEnx-1B engines. Further investigation is under way.