The investigation into last month's Air India Dreamliner crash in Ahmedabad city is "far from over," CEO Campbell Wilson has said in an internal memo, adding that the airline is open to further inquiries and warned against "premature conclusions".
The memo, seen by Reuters, comes after a preliminary report on Saturday showed confusion in the cockpit shortly before the Air India jetliner crashed and killed 260 people last month, after the plane's engine fuel cutoff switches flipped almost simultaneously and starved the engines of fuel.
The Boeing Dreamliner bound for London from the Indian city of Ahmedabad began to lose thrust and sink shortly after takeoff, according to the report on the world's deadliest aviation accident in a decade released by Indian accident investigators.
The memo said that the preliminary report found no mechanical or maintenance faults and that all required maintenance had been carried out.
The report, issued by India's Aircraft Accident Investigation Bureau, did not offer any conclusions or apportion blame for the 12 June disaster, but indicated that one pilot asked the other why he cut off fuel, and the second pilot responded that he had not.
In its 15-page report, the investigation bureau said that once the aircraft achieved its top recorded speed, "the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec".
"In the cockpit voice recording, one of the pilots is heard asking the other why did he cut off. The other pilot responded that he did not do so," it said.
The aircraft quickly began to lose altitude.
The switches then returned to the "RUN" position and the engines appeared to be gathering power, but "one of the pilots transmitted 'MAYDAY MAYDAY MAYDAY'", the report said.
Air traffic controllers asked the pilots what was wrong, but then saw the plane crashing and called emergency personnel to the scene.
Last week, specialist website The Air Current, citing multiple sources familiar with the probe, reported it had "narrowed its focus to the movement of the engine fuel switches", while noting that full analysis will "take months - if not longer".
It added that "the focus of the investigators could change during that time".
The Indian agency's report said that the US Federal Aviation Administration had issued an information bulletin in 2018 about "the potential disengagement of the fuel control switch locking feature".
Though the concern was not considered an "unsafe condition" that would warrant a more serious directive, Air India told investigators it did not carry out suggested inspections as they were "advisory and not mandatory".
One passenger survived, a British citizen who was seen walking out of the wreckage
Air India was compliant with all airworthiness directives and alert service bulletins on the aircraft, the report said.
The investigations bureau said there were "no recommended actions to B787-8 and/or GE GEnx-1B engine operators and manufacturers", suggesting no technical issues with the engines (GE) or the aircraft (Boeing).
The bureau said the investigation was ongoing, and that additional evidence and information has been "sought from the stakeholders".
The UN's International Civil Aviation Organisation stipulates that states heading an investigation must submit a preliminary report within 30 days of an accident.
US and British air accident investigators have taken part in the probe.
The plane was carrying 230 passengers, 169 Indians, 53 British, seven Portuguese and a Canadian, along with 12 crew members.
Dozens of people on the ground were injured.
One passenger miraculously survived, a British citizen who was seen walking out of the wreckage of the crash, and who has since been discharged from hospital.
Health officials in the Indian state of Gujarat initially said at least 279 people were killed, but forensic scientists reduced the figure after multiple scattered and badly burnt remains were identified.
