Pilots discussed fuel cutoff seconds before the crash: Preliminary AI171 Crash Investigation

New Delhi – A devastating revelation from the preliminary AI171 Crash Investigation report suggests a perplexing sequence of events leading to the tragic June 12 crash in Ahmedabad. Just seconds after the Air India Boeing 787 Dreamliner, flight AI171, lifted off the runway, fuel supply to both of its engines was abruptly cut off. This startling finding, detailed in the 15-page report by the Aircraft Accident Investigation Bureau (AAIB), paints a grim picture of the final moments aboard the ill-fated flight that claimed 260 lives.

Initial Findings of the AI171 Crash Investigation

The preliminary AI171 Crash Investigation indicates that approximately three seconds after getting airborne from Ahmedabad, the fuel cutoff switches for both Engine 1 and Engine 2 transitioned from the “RUN” to the “CUTOFF” position, with merely a one-second gap between them. This immediate cessation of fuel supply caused the engines’ fan speeds (N1 and N2) to drop significantly, and the heavily laden aircraft, weighing close to its maximum takeoff weight of 213.4 tons, began to rapidly lose altitude.

A crucial and unsettling detail emerged from the cockpit voice recording: “One of the pilots is heard asking the other why he cut off (the fuel), to which the other pilot responded that he did not do so.” This exchange reveals a profound confusion and distress among the flight crew regarding the uncommanded fuel cutoff. The report does not specify which pilot made the remarks, leaving the question of intent or inadvertent action unanswered for now.

The Desperate Seconds: Attempted Recovery and Mayday Call

As the engines faltered, the aircraft’s Ram Air Turbine (RAT), an emergency power source, automatically deployed during the initial climb, signaling a critical loss of power to essential systems. In a desperate attempt to regain thrust and control, the pilots re-engaged the fuel switches within seconds, returning them to the “RUN” position. While Engine 1 showed signs of beginning to recover, Engine 2 failed to stabilize or relight despite these efforts.

The AI171 Crash Investigation outlines a horrifying timeline:

• 08:08:39 UTC: Aircraft lifts off.
• 08:08:42 UTC: Aircraft achieves maximum airspeed of 180 knots; Engine 1 and Engine 2 fuel cutoff switches transition to “CUTOFF”.
• 08:08:52 UTC: Engine 1 fuel cutoff switch goes back to “RUN”.
• 08:08:56 UTC: Engine 2 fuel cutoff switch goes back to “RUN”.
• 08:09:05 UTC: Pilots issue a “MAYDAY MAYDAY MAYDAY” call.

The flight lasted approximately 30 seconds between lift-off and the eventual impact. Despite the pilots’ frantic attempts to recover, the low altitude and insufficient time prevented a successful relight and recovery of thrust, leading to the aircraft crashing into residential buildings outside the airport perimeter, including a medical college hostel. The impact scattered wreckage over a thousand feet, causing significant damage and further casualties on the ground.

Unanswered Questions and Ongoing Investigation into the AI171 Crash

The preliminary AI171 Crash Investigation report emphasizes that at this stage, there are no recommended actions to operators of Boeing 787-8 aircraft or GE GEnx-1B engines, suggesting that no immediate mechanical or design fault has been definitively identified as the cause. This indicates the complexity of the investigation, which is still seeking to understand how and why the fuel cutoff switches moved.

Records indicate that the aircraft, registered VT-ANB and in service since 2013, had undergone throttle control module replacements in 2019 and 2023, though these were not linked to fuel control switch issues. The report also notes that a 2018 Special Airworthiness Information Bulletin (SAIB) from the US Federal Aviation Administration (FAA) warned of potential disengagement of the fuel control switch locking feature on Boeing 737 models. While this was advisory and not a directive, it raises questions about potential vulnerabilities in similar systems.

Both pilots, Captain Sumeet Sabharwal and First Officer Clive Kundar, were experienced, with sufficient flight hours on the Boeing 787. They had also received adequate rest before the flight, ruling out fatigue as a primary factor. Fuel samples from the aircraft were tested and found satisfactory.

The AI171 Crash Investigation is ongoing, with investigators meticulously reviewing additional evidence, including cockpit voice recordings, flight data recorders, and component inspections. The final report, which is expected to conclusively identify the probable causes, will likely take several more months to complete given the intricate nature of aviation accident probes. The aviation community, and indeed the world, awaits the full findings to understand what led to this devastating and perplexing disaster.