What are the Air India crash theories and what happens next in the investigation?

Yahoo

14 hours ago

Investigators have not ruled out sabotage as a cause for the Air India plane crash this month that killed 274 people.
Flight AI171 bound for London Gatwick crashed just after take-off from Ahmedabad Airport on 12 June, killing all but one of the 242 people on board as well as nearly 30 people on the ground.
Security CCTV footage from the airport showed the Boeing 787-8 Dreamliner taking off before, moments later, starting to descend and then crashing and exploding into flames.
On Sunday, India's civil aviation minister said investigators are looking into all possible causes of the disaster, including sabotage.
Experts have told Yahoo News they regard sabotage as one of the less likely causes of the crash and warned that the nature of the incident could hamper efforts to recover data from the aircraft's block box.
As it also emerged that a report into the causes of the crash will be published in three months, Yahoo News UK looks at the potential theories behind the disaster.
The plane's pilot, Captain Sumeet Sabharwal - a veteran with 8,200 hours of flying experience - radioed air traffic control moments after take-off to say: "No thrust. Mayday, mayday."
A report in the Wall Street Journal suggested that the aircraft's emergency power generator, known as the ram air turbine (RAT), was operating when the plane crashed, which aviation experts said indicated engine power failure may have been the cause.
This system generates electricity and hydraulic pressure to ensure pilots can control the plane even if both engines fail.
The likelihood of both engines failing is very rare, but can be caused by a bird strike. However, experts appear to have ruled out a bird strike, given none were visible in the CCTV footage of the crash.
Some experts have said that CCTV footage shows the aircraft's wing flaps were not extended during take-off.
This would have reduced lift during take-off in the 40C heat in India that requires higher flap settings.
The plane's landing gear also appeared to be deployed, instead of being withdrawn upon leaving the runway.
One theory is that the landing gear got stuck and that the pilots partially retracted the flaps to reduce drag in an attempt to keep climbing. However, if overdone, this could cause the plane to lose lift.
Another possible cause being considered by investigators is fuel contamination, which can cause a double engine failure.
Investigators will no doubt examine what fuel the Air India plane was using, the maintenance of refuelling equipment used at the airport and where exactly it was stored.
The AAIB is also expected to look into whether the fuel was contaminated as part of a deliberate act of sabotage.
On Sunday, Murlidhar Mohol, India's civil aviation minister, said that investigators from the country's Aircraft Accident Investigation Bureau (AAIB) were examining all of the potential causes of the crash, and that this included sabotage.
In an interview with New Delhi Television (NDTV), he described the crash as an "unfortunate accident".
However, he then spoke about the AAIB investigation into the disaster, saying: "It is being probed from all angles, including any possible sabotage.
"The CCTV footage is being reviewed and all angles are being assessed. Several agencies are working on it."
Aerospace engineering expert Dr Jason Knight, a senior lecturer in fluid mechanics at the University of Portsmouth, told Yahoo News he didn't think sabotage would be found to be the cause of the disaster.
"Whilst sabotage is a possibility, in my opinion, it would be highly unlikely as the cause of the accident," he said, pointing out it is standard practice to examine if sabotage is a factor in air disasters.
"They will leave no stone unturned and investigate all possibilities, including sabotage as a cause - regardless of how unlikely it is to be the cause," he said.
At the end of last week, investigators began downloading data from the two black boxes that were recovered after the crash.
The cockpit voice recorder (CVR) and flight data recorder (FDR) were located in the aftermath of the crash - one on the following day on the rooftop of a building and the other among the debris three days after the disaster.
The Indian government said last week that the AAIB had started extracting the data from the black boxes after they were taken to New Delhi.
Mohol dismissed reports that the black boxes would be sent outside the country for assessment, saying the AAIB will do the "entire investigation" and that a report into the causes of the crash will be published in three months.
"Once the report comes, we will be able to ascertain if it was an engine problem or fuel supply issue or why both the engines had stopped functioning," he said.
Dr Knight told Yahoo News: "The AAIB will want to be confident in their findings and will need time to gather evidence and examine all the findings. They will be using multiple sources of information to investigate and corroborate the actual cause."
Dr Akhil Bhardwaj, a disasters expert and senior lecturer at the University of Bath, told Yahoo News the speed at which the incident happened may hamper the investigation.
"Data from the recovered black box should enable investigators to zoom in on what went wrong," he said. "The short timeframe within which the event happened can make it more difficult to parse the data because many indicators might be confounded with each other and difficult to disentangle neatly.
"This will take some time and investigators will naturally want to be careful about any report they release."
Under United Nations (UN) rules, the AAIB must release a preliminary report on the crash within 30 days of the disaster.
Investigators will also be looking at the possibility of any criminal charges. 'If there is evidence of criminal wrongdoing or negligence, one can imagine that charges will be brought," Dr Bhardwaj said.
He pointed out that aeroplane manufacturer Boeing faced criminal charges after 346 people died in two similar plane crashes in Indonesia in October 2018 and Ethiopia in March 2019 involving 737 MAX aircraft.
It was reported last month that Boeing will avoid prosecution for fraud in the US following a deal with the justice department that will involve it paying more than $1.1bn, as well as an additional $445m for the crash victims' families.
Speaking about the Air India crash, Dr Bhardwaj said: "Understandably, any suggestion that Boeing was responsible for the crash would be highly unwelcome, especially as the company is only now beginning to recover from the reputational damage caused by the 737 MAX incidents.
"It remains to be seen whether this disaster was a one-off or if there are systematic issues that need to be addressed and there are lessons to be learned from it.'
Boeing said in a statement it is ready to support any investigation.