Sequence of Events
The aircraft lifted off the runway at 08:08:39 UTC. Approximately three seconds after takeoff, at an altitude of about 150 feet and a speed of around 180 knots, both fuel control switches suddenly moved from the RUN to the CUTOFF position. This resulted in an immediate interruption of fuel flow to both engines, causing them to shut down.
The loss of thrust activated the Ram Air Turbine (RAT), which temporarily supplied power to essential hydraulic and electrical systems. The aircraft began to descend in a slight bank. In the following seconds, the pilots managed to return one of the switches to the RUN position. The left engine (Engine 1) began to restart, but not quickly enough to keep the aircraft airborne.
Thirty-two seconds after takeoff, the Boeing impacted a residential building approximately 0.9 nautical miles from the end of the runway. There was only one survivor on board. Tragically, nineteen people on the ground also lost their lives.
Cockpit Voice Recorder
Investigators quoted excerpts from the Cockpit Voice Recorder (CVR) that capture the crew’s surprise:
– “Why did you shut it off?”
– “I didn’t shut it off.”
The conversation indicates that the fuel switches were not moved as a deliberate act by either pilot. The report also states that both switches were moved in an extremely short time frame—within one second.
Technical Background
The report notes that both fuel control switches were found in an intermediate physical position (between RUN and CUTOFF), but the Flight Data Recorder (FDR) registered their electronic state as CUTOFF.
Investigators also reported that related modules on the aircraft’s instrument panel had been replaced twice before, in 2019 and 2023. However, Air India had not implemented all FAA recommendations from 2018 regarding the replacement of this specific type of switch.
It is not yet clear whether the incident was caused by a technical failure, human error, or an intentional crew action. The report explicitly states that no evidence of sabotage was found.
Next Steps in the Investigation
The AAIB will continue its investigation, focusing on:
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a detailed analysis of the fuel control switch mechanism,
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an examination of potential faults in the electronics or wiring,
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a simulation of human factors in crew decision-making,
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a thorough audit of all maintenance actions performed on the aircraft.
The final report is expected in the coming months.
Implications and Broader Context
The tragedy of flight AI171 highlights the fragility of the aviation safety chain—whether due to technical failure, non-compliance with recommended service procedures, or a misunderstanding in the cockpit. The investigation raises numerous questions for European operators of the Boeing 787 as well.
If defects in this specific type of switch or its installation are confirmed, the issuance of new Airworthiness Directives (ADs) can be expected, extending beyond India.
You can read the full preliminary report HERE.
Sources: AAIB Preliminary Report VT-ANB, Times of India, NDTV
