Ahmedabad, July 12, 2025 — A preliminary report released by India’s Aircraft Accident Investigation Bureau (AAIB) has shed light on the catastrophic crash of Air India Flight AI171, a Boeing 787-8 Dreamliner, which claimed 260 lives on June 12, 2025, in Ahmedabad. The 15-page report details a sequence of events that led to the aircraft crashing just 32 seconds after takeoff, marking the first fatal incident involving a Boeing 787 Dreamliner. The findings point to a mysterious movement of fuel cutoff switches, pilot confusion, and a missed opportunity to address a known mechanical issue, raising serious questions about safety protocols at Air India.

Timeline of the Disaster

The tragic sequence unfolded as follows, based on the AAIB’s preliminary report and black box data:

• 07:48:38 UTC (1:18:38 PM IST): Flight AI171, bound for London Gatwick from Ahmedabad’s Sardar Vallabhbhai Patel International Airport, began pushback from Bay 34. The aircraft, registered as VT-ANB, carried 230 passengers and 12 crew members, including two infants, with a takeoff weight of 213,401 kg and 54,200 kg of fuel.
• 07:55:15 UTC: The crew received taxi clearance and proceeded via Taxiway R4 to Runway 23.
• 08:02:12 UTC: Pre-takeoff checks were completed, with flaps set at 5 degrees and landing gear in the down position, both standard for takeoff.
• 08:02:25 UTC: Air Traffic Control (ATC) cleared the Dreamliner for takeoff.
• 08:02:45 UTC: The aircraft began its takeoff roll, reaching a maximum airspeed of 180 knots IAS by 08:08:42 UTC.
• 08:08:42 UTC: Just three seconds after liftoff, both engine fuel cutoff switches transitioned from RUN to CUTOFF within one second of each other, abruptly halting fuel supply to both General Electric engines. Engine fan rotation speeds (N1 and N2) began to drop below minimum idle speed.
• 08:08:47 UTC: The Ram Air Turbine (RAT), an emergency power source, automatically deployed, as captured by airport CCTV, indicating a total loss of engine thrust.
• 08:08:52 UTC: The fuel cutoff switch for Engine 1 was moved back to RUN, followed by Engine 2’s switch at 08:08:56 UTC. The Full Authority Digital Engine Control (FADEC) initiated automatic relight attempts.
• 08:09:05 UTC: One pilot transmitted a desperate “MAYDAY MAYDAY MAYDAY” call. ATC requested the aircraft’s callsign but received no response.
• 08:09:11 UTC: Flight data recording ceased. The aircraft, in a nose-up attitude of 8 degrees, crashed 0.9 nautical miles (1.6 km) from the runway, striking a hostel at BJ Medical College and five other buildings, triggering a massive fire. The wreckage scattered widely, with the vertical stabilizer, wings, and engines separated.

Only one passenger, Vishwash Kumar Ramesh, a British national seated in 11A, survived, escaping through a fuselage opening. The crash killed 241 of the 242 people onboard and 19 on the ground, making it India’s deadliest aviation disaster in decades.

Cockpit Confusion: “Why Did You Cut Off?”

Cockpit Voice Recorder (CVR) data revealed a chilling exchange between the pilots. One pilot asked, “Why did you cut off?” referring to the fuel switches, to which the other replied, “I didn’t.” The report does not specify which pilot—Captain Sumeet Sabharwal or First Officer Clive Kunder—made each remark. This exchange suggests neither pilot intentionally moved the switches, pointing to either an inadvertent action or a mechanical failure. The fuel cutoff switches, located between the pilots’ seats behind the throttle levers, are guarded by metal bars and a locking mechanism to prevent accidental movement, typically used only during emergencies like engine fires or after landing.

Engine Relight Attempts and Failure

After the switches were moved back to RUN, the FADEC system attempted to relight the engines. Engine 1 showed signs of recovery, with its core speed stabilizing, but Engine 2, despite relighting, failed to regain thrust. The low altitude (approximately 650 feet) and brief 32-second flight left no time for recovery. The RAT’s deployment provided limited hydraulic and electrical power to control surfaces, but the landing gear remained down, and the Auxiliary Power Unit (APU), which activated automatically, took too long to start (approximately 90 seconds under standard conditions) to make a difference.

No External Factors: Clean Fuel, Clear Skies

The AAIB ruled out several potential causes:

• Fuel Quality: Samples from the airport’s refueling systems and the aircraft’s remains tested clean, with no contamination.
• Weather: Conditions were calm, with light winds (250°/7 knots), 6,000-meter visibility, and no significant cloud cover.
• Bird Strikes: CCTV footage showed no significant bird activity near the flight path.
• Aircraft Configuration: Flaps (5 degrees), landing gear (down), and takeoff weight were within normal limits. No dangerous goods were onboard.

Pilot Credentials and Condition

The crew was highly experienced and fit for duty:

• Captain Sumeet Sabharwal, 56, had 15,638 flying hours, including 8,596 on the Boeing 787. A Mumbai-based Air India instructor, he was well-rested and lived with his elderly father, planning for retirement.
• First Officer Clive Kunder, 32, had 3,403 flying hours, with 1,128 on the Dreamliner. He joined Air India in 2017 and was also Mumbai-based, arriving in Ahmedabad the day before with adequate rest.

Both pilots were medically fit, with no evidence of fatigue or procedural errors. Kunder was the pilot flying, while Sabharwal was the pilot monitoring.

FAA Advisory Ignored: A Missed Warning?

A critical detail in the report is a 2018 Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin (SAIB NM-18-33), which flagged a potential issue with the locking mechanism of fuel control switches on Boeing aircraft, including the 787’s part number 4TL837-3D. The bulletin noted that some switches were installed with the locking feature disengaged, but it was advisory, not mandatory. Air India did not conduct the recommended inspections on VT-ANB, despite maintenance records showing the throttle control module was replaced in 2019 and 2023. The report does not confirm whether this flaw caused the switches to move but notes it as a point of investigation.

Investigation Focus and Unanswered Questions

The AAIB report emphasizes that the investigation is ongoing, with no conclusive cause determined. Key areas of focus include:

• Fuel Switch Movement: Whether the switches were moved intentionally, inadvertently, or due to a mechanical or electronic failure. U.S. aviation experts, including John Cox and John Nance, state that accidental movement is unlikely due to the switches’ guarded design, suggesting either deliberate action or a rare system malfunction.
• Pilot Actions: The CVR’s lack of discussion about a planned engine shutdown rules out a response to a perceived emergency like an engine fire, which would have triggered illuminated fire handles.
• Mechanical Issues: The FAA advisory and Air India’s failure to inspect the switches raise questions about maintenance oversight. However, no immediate mechanical failures were found in the engines or other systems.
• Black Box Data: The flight data recorder (FDR) and CVR, recovered intact, provide precise details on switch positions, engine parameters, and pilot communications, but the cause of the switch movement remains unclear.

Air India’s Response and Industry Implications

Air India issued a statement acknowledging the report and pledging full cooperation with the AAIB and other authorities. “Air India stands in solidarity with the families and those affected by the AI171 accident,” the airline posted on X. “We continue to mourn the loss and are fully committed to providing support during this difficult time.” The U.S. National Transportation Safety Board (NTSB), assisting due to Boeing and General Electric’s involvement, noted no immediate recommendations for 787 operators, suggesting no fleet-wide design flaws.

The crash has intensified scrutiny on Air India’s maintenance and safety practices. Recent reports indicate the airline faced warnings for flying aircraft with overdue checks and improper maintenance, though no systemic issues were found with its 787 fleet.

What’s Next?

Under International Civil Aviation Organization (ICAO) rules, a final report is expected within a year. Investigators will analyze maintenance records, Boeing’s Aircraft Communications Addressing and Reporting System (ACARS) data, and simulator recreations of the flight. The focus on the fuel switches, combined with the FAA advisory, suggests a deeper probe into both human factors and potential design or maintenance lapses.

The tragedy, India’s worst aviation disaster in decades, has left families, regulators, and the aviation industry searching for answers. As the investigation continues, the haunting cockpit audio—“Why did you cut off?” “I didn’t”—underscores the mystery at the heart of this disaster.