Cockpit switches critical for the fuel supply for engines on the Air India plane that crashed soon after takeoff from Ahmedabad in India in June were switched off, according to a preliminary report.

The cockpit voice recorder on the London-bound Boeing 787 Dreamliner that crashed on June 12 has captured confusion between the pilots about how the fuel-control switches came to be switched off, with no clear explanation yet.

Newsweek has contacted Boeing and Air India for comment.

Why It Matters

India’s Aircraft Accident Investigation Bureau (AAIB) has released a report that highlights cockpit confusion prior to the crash of Air India Flight 171 into a neighborhood in Ahmedabad, killing 260 people—all but one of those on board and 19 on the ground.

While a more detailed probe will be released later in the year, the initial findings will add to questions over whether the crash was the result of pilot error or not, with manufacturer Boeing, Air India and aviation safety in general also under scrutiny.

What To Know

After the Air India flight climbed to 625 feet, the aircraft’s signal was lost 50 seconds into the flight in clear conditions. CCTV images showed the deployment of a backup energy source called a ram air turbine that showed a loss of power from the engines.

The report said that fuel switches had flipped to cutoff, which is a move typically done only after landing. On the cockpit voice recorder, one pilot asked the other why he cut off the fuel and his colleague replied that he hadn’t.

The commanding pilot was Sumeet Sabharwal, 56, with 15,638 hours of experience and his co-pilot Clive Kunder, 32, had 3,403 hours, although it is so far unclear which pilot said what during the exchange.

The switches, which are designed to prevent accidental activation, flipped a second apart, the report said, roughly the time it would take to shift one and then the other, according to U.S. aviation expert John Nance. He told Reuters a pilot would normally never turn the switches off in flight, especially if an aircraft is climbing.

He also told NBC news that the report’s findings “almost totally rules out mechanical failure.”

Both fuel switches were found in the run position with indications that both engines were relighting before the crash, said the report. The report said that the plane had complied with all airworthiness directives.

Scrutiny remains on Air India, whose budget airline Air India Express, faces an investigation by the European Union Aviation Safety Agency after Reuters reported the carrier did not follow a directive to change engine parts of an Airbus A320 in a timely manner and falsified records to show compliance.

Demetrius Danas, an aviation lawyer at Irwin Mitchell told Newsweek in June that the families of those in the crash must get the answers and specialist support they deserve and “shouldn’t feel pressured into accepting early settlements without understanding their full legal rights.”

Meanwhile, the U.S. National Transportation Safety Board said there were no recommended actions in the report aimed at operators or manufacturers of Boeing 787 jet engines.

Boeing said it continued to support its customer, Air India and the investigation, which will release a more detailed report later this year, according to Reuters.

What People Are Saying

Shawn Pruchnicki, aviation expert at Ohio State University told the BBC that the report: “Does beg the question: why…pull the switches to the off position? Was it intentional, or the result of confusion?…This kind of error doesn’t typically happen without some evident issue.”

U.S. aviation safety expert Anthony Brickhouse told Reuters: “If they were moved because of a pilot, why?”

U.S. aviation expert John Nance told NBC News: “For any experienced pilot, there is no question in your mind what is going to happen if you turn these [switches] off so the question in my mind, was this some sort of mental aberration or was this purposeful?”

What Happens Next

The report said that additional details are being gathered based on the initial leads and that the investigation team “will review and examine additional evidence, records and information that is being sought from the stakeholders.”