The findings could explain why the aircrafts emergency-power generator, known as a ram air turbine, appeared to have been activated moments before it plummeted to the ground.
At this stage of investigation, there are no recommended actions to Boeing 787-8 and/or GE GEnx-1B engine operators and manufacturers, Indias Aircraft Accident Investigation Bureau said.
Family members and relatives of Akash Patni, a victim of the Air India plane crash, grieve during his funeral procession in Ahmedabad last month. Credit: AP
Air India released a statement on the report, saying on X it was cooperating with Indian authorities as the investigation continues.
The airline wrote on X that the airline stands in solidarity with the families and those affected. It did not address specific findings in the report.
Boeing and GE Aerospace did not respond immediately to requests for comment.
The agency, an office under Indias civil aviation ministry, is leading the probe into the worlds deadliest aviation accident in a decade.
Air India flight 171 crashed on take-off from Ahmedabad, killing all but one of the 242 passengers and crew on June 12, along with 19 people on the ground. The cause has remained a mystery.
A retired captain with experience flying wide-body aircraft said an accidental shift in the fuel switches would be impossible.
If you lift the fuel control switches, its a double action. So you have to lift them and pull them rearwards that will cause the engine to shut down pretty well immediately, the former captain said.
The switches have to be lifted up and then pulled over a detent, or a catch in the slot, which locks them into position, said the former captain, who noted that a plane cannot take off with switches in an off position.
The only time you would use those switches as part of a shutdown on restart checklist, you would attempt to recycle to start switches on the engine to cause the engine to re-light (as we say in the business), the retired captain said.
The tail of the Air India plane became wedged in the dining hall of a medical students hostel. Credit: Getty
I can assume, possibly, that one or other pilots turn both fuel control switches off just before the crash in order to minimise the fire risk, but thats only an assumption, and its an extreme assumption.
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Air accident
In the absence of a direct suicide attempt by one or the other of the pilots and theres no indication of that I cant see why the switches wouldve been turned off.
They certainly wouldnt have been turned off inadvertently.
You cannot bump those switches and inadvertently drag them aft. Nor can you do that to both. You have to individually grab the switch and rotate it to the after position to stop the engine.
There are only two reasons they would have turned off the engines, the retired captain said, one would be a frantic attempt to get the engines to restart.
But the engine would take 30 to 45 seconds to spool back up, the ex-captain said.
The other possibility was that they knew they were going to crash, so they just shut the switches to minimise their total fire risk.
If they did that, they were very brave and confident men and thinking about what they were doing right to the end.
Catastrophic crash
The Boeing 787 Dreamliner, bound for Gatwick in Britain, lost altitude almost immediately after take-off, sinking and hitting buildings on the ground.
The apparent dual failure of its engines has raised questions about the cause of the catastrophe. The Boeing Dreamliner has had a strong safety record, and the findings of the investigation are being closely watched for fallout for the Indian airline and the US aircraft manufacturer.
Asked for a comment from Boeing, the company said: Consistent with US law and the UN International Civil Aviation Organisation protocol known as Annex 13, we will refer you to Indias Aircraft Accident Investigation Bureau for any information.
Indias aircraft accident bureau recently contradicted reports in Indian media by saying the flight black boxes had survived the crash and were expected to yield good data, Reuters reported.
Black boxes routinely record 300 parameters of information that can be parsed and compared with cockpit conversation and other sounds from the last minutes of the crash to understand what the cause was.
Boeing has been beset by a number of troubles linked to previous crashes of its planes, which have raised questions about the future of the aircraft maker behemoth.
An issue linked to a flawed flight control system was determined to be the cause of the Indonesian Lion Air Boeing 737 Max crash in 2018 and the Ethiopian Airlines crash of the same model in 2019. The global fleet of 737 Max aircraft was grounded. Regulators in the US have forced Boeing to slow down the production of planes while it examines its work and safety practices.
The delays have weakened Boeings competitive position against its lone peer plane maker, Airbus. Both manufacturers have had their production levels struggle amid supply chain disruptions driven by the COVID shutdowns.
