By Soutik Biswas
India Correspondent – @soutikBBC

Investigators probing the crash of Air India Flight 171, which killed 260 people in June, have uncovered a chilling detail: just seconds after takeoff, both engine fuel control switches were unexpectedly turned to “cut-off” — a move typically reserved for after landing. This sudden shutoff starved both engines of fuel, causing a catastrophic loss of power.

The cockpit voice recording only deepens the mystery. One pilot can be heard asking the other, “Why did you do the cut-off?” The response: “I didn’t.” However, it’s unclear who said what. At the time, the co-pilot was flying the aircraft while the captain was monitoring.

While the crew quickly reset the switches to their normal inflight position, triggering an automatic engine relight, it was already too late. One engine had started regaining thrust, the other was still lagging. Within 40 seconds of liftoff, the Boeing 787 Dreamliner crashed into a densely populated area in Ahmedabad, making it one of India’s most baffling air disasters in recent years.

A Puzzle Wrapped in Technology

Flight data shows that the plane climbed to just 625 feet before losing location data approximately 50 seconds into the flight. A preliminary 15-page report released Saturday sheds light on the sequence of events but leaves major questions unanswered.

The investigation is being led by Indian authorities in coordination with experts from Boeing, General Electric, Air India, and regulatory officials from the US and UK.

A key focus is on the lever-lock fuel switches, which are built to prevent accidental shutoff. These switches, in use since the 1950s, require deliberate upward pulling to unlock before flipping, and protective guards make unintentional activation almost impossible.

“That’s what makes this incident so extraordinary,” said a Canadian air crash investigator, speaking anonymously. “You simply can’t knock both switches off by mistake. It takes deliberate action with both hands.”

Was It Human Error — or Something More?

Aviation expert Shawn Pruchnicki, a former airline accident investigator now at Ohio State University, noted the lack of distress signals or cockpit confusion.

“This doesn’t appear to be a case of accidental button pushing in a panic. There’s no indication the pilots were reacting to a malfunction or emergency,” he said. “So, if one of them did switch off the engines — why?”

Peter Goelz, former managing director of the US National Transportation Safety Board (NTSB), called the finding “deeply disturbing.” He believes the cockpit voice recorder may hold more critical information.

“One stray comment isn’t enough. We need a full transcript, speaker identification, and all audio from pushback to crash,” he said. Goelz also backed long-standing NTSB recommendations for cockpit video recorders, which could definitively show who touched the switches.

At this point, investigators still don’t know which pilot moved the controls — or why.

FAA Warning from 2018 Resurfaces

An intriguing detail in the report cites a 2018 Special Airworthiness Information Bulletin (SAIB) from the US Federal Aviation Administration. It warned that some Boeing 737 fuel control switches may have been installed with their locking mechanism disengaged. Though advisory and not mandatory, this issue was not addressed on Air India’s Boeing 787-8 aircraft — which uses the same design.

Still, experts are split. Pruchnicki sees this as potentially serious. “Could a faulty switch move on its own if the lock was disabled? That must be clarified.”

Others are less convinced. “This SAIB wasn’t widely flagged. Pilots would have complained if the switches had issues,” said Goelz. “It could be a red herring.”

Capt Kishore Chinta, formerly with India’s Aircraft Accident Investigation Bureau (AAIB), raised another possibility — an electronic trigger.

“Could the plane’s control unit have tripped the fuel cut-off switches? If so, that opens an entirely new line of inquiry,” he said.

Other Theories Fall Short

Initial theories about contaminated fuel have been ruled out — fuel samples passed all tests. The aircraft’s Ram Air Turbine (RAT), a backup power source that deploys only in extreme situations, was found extended — confirming both engines had indeed failed mid-air.

Additionally, the landing gear was never retracted. A Dreamliner pilot explained this wasn’t unusual: “From takeoff to full gear retraction takes about eight seconds. At 200 feet, that’s your focus. But if both engines fail right away, your only thought is: where can I land?”

The timeline was simply too short.

“The pilots attempted recovery,” said Pruchnicki. “They restarted the left engine first. The right one was slower to respond. Ultimately, both engines were back on, but not in time. The left had already shut down, and the right didn’t deliver enough thrust.”

What Lies Ahead

Investigators are calling for:

• Clear voice identification in the cockpit audio
• A complete transcript of crew communication
• Consideration of cockpit video monitoring for future flights

Despite passing breathalyser tests and being declared fit, the actions of one or both pilots remain a key focus.

Until more data is analyzed, including voice matching and full systems diagnostics, the central question lingers:

Why were both fuel switches turned off seconds after takeoff — and by whom?