A year has passed since Air India flight AI-171 plunged from the skies above Ahmedabad and exploded into the BJ Medical College campus, killing 260 people and leaving behind one of the most baffling mysteries in Indian aviation history.
The Boeing 787 Dreamliner was meant to be a routine flight from Ahmedabad to London Gatwick. Instead, it became a disaster that unfolded in just 32 seconds — a chain of events so brief that investigators are still struggling to explain exactly why it happened.
For the families of the dead, that uncertainty has become its own burden.
“We hear different versions every few months,” said Muktiben Vansadiya, who lost both her parents on what was their first-ever flight. “But nobody can tell us exactly what happened.”
What investigators have established is a devastating timeline that begins on a hot June afternoon and ends half a minute later in a fireball.
A routine departureJune 12, 2025, began like any other travel day at Ahmedabad airport.
Passengers checked in for Air India flight AI-171, a Boeing 787-8 Dreamliner scheduled to fly to London Gatwick.
Among the 242 people on board were students, families, professionals travelling overseas and former Gujarat chief minister Vijay Rupani.
Nothing in the aircraft's records suggested trouble ahead.
Investigators later found that the weather was favourable. Visibility was clear. Winds were light. The aircraft was within weight and balance limits. Fuel quality tests returned satisfactory results. There was no evidence of a bird strike. The flaps were correctly configured and the landing gear was operating normally.
The Dreamliner accelerated down the runway and lifted smoothly into the afternoon sky.
For a few seconds, everything appeared entirely normal.
Then something happened that investigators are still trying to explain.
Three seconds after take-offAccording to data recovered from the aircraft's flight recorders, both fuel control switches in the cockpit moved from the RUN position to CUTOFF.
The movement did not occur minutes into the flight or during an emergency. It happened roughly three seconds after the aircraft became airborne.
The switches moved one after another, separated by only a tenth of a second.
To aviation experts, the significance of that action is enormous.
Fuel control switches regulate the flow of fuel to the engines. When moved to cutoff, fuel supply is interrupted. Without fuel, engines cannot continue producing thrust.
The effect on AI-171 was immediate.
The aircraft had only just left the runway and was still climbing. It had not reached a safe altitude. There was little room for error and almost no time available for recovery.
As fuel supply ceased, both engines began losing power.
Within moments, the Dreamliner that had been climbing toward London was effectively becoming a glider.
The conversation that changed the investigationThe most revealing evidence recovered from the aircraft is not a mechanical component or a piece of wreckage.
It is a brief conversation recorded inside the cockpit.
According to the AAIB's preliminary report released last year, one pilot is heard asking the other why he had cut off the fuel.
The reply came almost immediately.
He had not done so.
The report deliberately avoided identifying which pilot said what.
It did not publish a full transcript.
It did not draw conclusions.
It simply recorded the exchange and moved on.
Yet that single conversation has become the focal point of the entire investigation.
From that moment onward, the debate surrounding AI-171 split into competing camps.
Pilot groups argued that the exchange should not be interpreted as evidence of deliberate action by either crew member.
They warned against drawing conclusions before the technical investigation was complete and insisted that the possibility of a system malfunction remained open.
Others focused on the recorded movement of the fuel switches and the sequence of events that followed.
A year later, investigators still have not publicly explained why the switches moved.
A desperate attempt to save the aircraftWhat happened next is a reminder that the final seconds of AI-171 were not passive.
The crew fought until the very end.
Flight recorder data showed that within 10 to 14 seconds of the fuel cutoff event, both switches were moved back to the RUN position.
The pilots were attempting to restore power.
The engines responded.
Investigators found evidence that restart sequences had begun.
One engine showed signs of relighting.
The other was attempting to recover.
The aircraft was no longer simply falling; there were indications that the crew had managed to begin reversing the catastrophe.
But aviation is governed by altitude, speed and time.
The Dreamliner had almost none of those left.
At the moment the engines lost power, the aircraft was only around 625 feet above the ground.
That left the crew with a vanishingly small window in which to diagnose the problem, restart the engines and recover a fully loaded wide-body aircraft.
Modern jet engines do not instantly spring back to life.
Restart procedures take precious seconds.
Sometimes they take longer.
The pilots simply ran out of sky.
The final descentAs AI-171 descended, its path carried it beyond the airport boundary and toward the BJ Medical College campus.
Investigators believe the aircraft first struck trees and an incineration chimney within the Army Medical Corps compound.
By then, the aircraft was already descending uncontrollably.
The collision sequence that followed scattered wreckage across hundreds of feet.
The right engine slammed into a concrete water tank and separated from the aircraft.
Sections of both wings tore away.
The vertical stabiliser and rudder detached from the tail and fell separately from the main fuselage.
The aircraft carved through buildings, walls and open ground before crashing into the hostel complex.
Students were inside the canteen at the time.
Seconds later, flames engulfed both the aircraft and parts of the buildings it had struck.
Investigators later mapped a debris field stretching across the campus.
The left engine came to rest near Building D.
The flight deck stopped hundreds of feet from the initial impact point.
Wing sections, landing gear and tail components were found embedded in buildings or scattered across the compound.
The violence of the crash left little chance of survival.
Of the 242 people on board, only one passenger lived.
Nineteen people on the ground also lost their lives.
What investigators know — and what they don'tOver the past year, investigators have steadily eliminated several possible causes.
The evidence does not support bad weather.
It does not support bird activity.
It does not indicate improper aircraft configuration.
Fuel contamination has been ruled out.
Both engines were functioning normally before fuel supply was interrupted.
The aircraft also had no known fuel-control-switch defects recorded in recent maintenance history.
Also read: A year after AI 171 crash , some questions answered, others remainYet ruling out possibilities is not the same as solving the mystery.
The central question remains exactly where it was a year ago: why did both fuel control switches move to cutoff seconds after take-off?
