Two groups of commercial pilots have rejected claims that human error caused an Air India plane crash that killed 260 people after a preliminary investigation found the aircraft’s engine fuel switches had been turned off.

The Indian Commercial Pilots Association (ICPA) and the Airline Pilots’ Association of India (ALPA India) issued statements on Sunday after the release of the initial findings, which showed that fuel control switches to the engines of Flight AI171 were moved from the “run” to the “cutoff” position moments before last month’s deadly impact.

The report sparked speculation by several independent aviation experts that deliberate or inadvertent pilot action may have caused the Boeing 787-8 Dreamliner to crash soon after takeoff from Ahmedabad in western India.

Flight AI171 was headed to London’s Gatwick Airport when it crashed on June 12.

The report on the crash, issued on Saturday by India’s Aircraft Accident Investigation Bureau (AAIB), did not offer any conclusions or apportion blame for the disaster but indicated that one pilot asked the other why he cut off the fuel and the second pilot responded that he had not.

After the switches flipped, the Boeing 787 Dreamliner immediately began to lose thrust and altitude, according to the report.

One pilot can be heard on the cockpit voice recorder asking the other why he had cut off the fuel. “The other pilot responded that he did not do so,” the report said.

It did not identify which remarks were made by the flight’s captain and which by the first officer or which pilot transmitted “Mayday, Mayday, Mayday” just before the crash.

No more details about the cockpit dialogue between the pilots were revealed.

The ICPA said it was “deeply disturbed by speculative narratives, … particularly the reckless and unfounded insinuation of pilot suicide”.

“There is absolutely no basis for such a claim at this stage,” it said in a statement. “It is deeply insensitive to the individuals and families involved.

“To casually suggest pilot suicide without verified evidence is a gross violation of ethical reporting and a disservice to the dignity of the profession.”

The ICPA was referring to a number of aviation experts suggesting engine fuel control switches can only be moved deliberately and manually.

United States-based aviation safety expert John Cox earlier said a pilot would not be able to accidentally move the fuel switches that feed the engines. “You can’t bump them and they move,” he told the Reuters news agency.

ALPA India, which has 800 members, also accused the investigative agency of “secrecy” surrounding the investigation, saying “suitably qualified personnel” were not involved in it.

“We feel that the investigation is being driven in a direction presuming the guilt of pilots and we strongly object to this line of thought,” ALPA India President Sam Thomas said in a statement issued on Saturday.

ALPA requested the AAIB be included as “observers so as to provide the requisite transparency in the investigations”.

Meanwhile, Air India CEO Campbell Wilson said the probe into last month’s crash is far from over and it is unwise to jump to any premature conclusions.

Wilson added: “The preliminary report identified no cause nor made any recommendations, so I urge everyone to avoid drawing premature conclusions as the investigation is far from over.”

The crash killed all but one of the 242 people on board as well as 19 people on the ground.