Unexpected fuel cutoff preceded Air India plane crash, preliminary report says

Indian investigators probing the crash of Air India flight 171 said that both engines stopped receiving fuel shortly after takeoff in a preliminary report documenting their findings regarding the nation’s worst airline crash in decades.

The new details from India’s Aircraft Accident Investigation Bureau about the June 12 crash indicate that the switches controlling fuel to both engines entered the cutoff position early into the flight, causing the plane to lose thrust.

The switches were later flipped back into the run position, a standard procedure for restarting the engines mid-flight.

Audio from the cockpit suggests both pilots were confused over the change to the switch setting. “In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff,” write the report’s authors. “The other pilot responded that he did not do so.”

The switches have safeguards designed to stop them being inadvertently moved.

“Each switch has a mechanical lock where you have lift the switch up and then move it, so it’s highly unlikely for switches like this to be inadvertently moved absent some mechanical failure,” said Jeff Guzzetti, the former director of the Federal Aviation Administration’s Accident Investigation Division.

It is also unusual that both switches inadvertently moved to the cutoff position “one right after another, one second apart,” Guzzetti added. Guzzetti did not rule out the possibility the switches may have been intentionally moved, citing the need to also investigate the pilots.

The preliminary report was released around 1 a.m. local time Saturday. The investigation is still in its early stages and is not likely to be complete for more than a year.

The Boeing 787 took off from Ahmedabad airport in western India before crashing down into a dormitory at a medical college, causing a massive fireball. All but one of the 242 people on the plane were killed, as were 19 people on the ground. One passenger made a miraculous escape from the doomed jet.

The airliner was bound for London’s Gatwick Airport. The plane appeared to roll down the runway and take off normally, according to experts who have reviewed videos from the scene. But after just a few seconds in the air, the jet stopped climbing. The pilots transmitted a mayday call 23 seconds after the first switch flipped into the cutoff position, according to the report.

The plane’s landing gear remained down and video and audio suggests an emergency device known as a ram air turbine, or RAT, had deployed on the plane, experts have said, potentially evidence of a rare double engine failure. The device drops from the bottom of an aircraft, spinning as it moves through the air to provide emergency power.

But in the weeks since the crash it has remained unclear what might have ultimately caused the plane to crash. Aviation news site The Air Current reported this week that investigators were focusing on the movement of fuel switches on the flight deck, citing people familiar with the probe. The switches are typically used to control the flow of fuel when starting and stopping the engine, but they can also be used if an engine needs to be restarted in flight.

The findings issued Friday are required under international standards governing crash investigations. But they are a summary of facts available to investigators and do not include conclusions about why the crash happened. It is likely to take investigators a year or more to complete their work. The U.S. National Transportation Safety Board is leading a team of Americans aiding the probe, but responsibility for releasing information remains with Indian officials.

The report’s authors note that they make no recommendations to Boeing, the manufacturer of the plane, or General Electric, the maker of the engine.

Authorities typically provide regular briefings to the public immediately after serious crashes, but in the case of the Air India crash little official information had been shared. That left a void filled in some cases by misinformation and it stoked concern among international safety experts that the lack of transparency would make it difficult for other airlines to know whether there were any broader safety risks that needed to be urgently addressed.

The investigation got off to a slow start. The plane’s black boxes, which record conversations between the pilots and log data from the jet’s systems, were recovered from the wreckage in the days after the crash. But investigators did not begin to analyze data from them until June 24 at a lab in Delhi. The information in the boxes will be vital to investigators as they piece together what went wrong.

The crash was the first involving a 787, a fuel-efficient Boeing jet first put into service in 2011. The new planes were briefly grounded in 2013 due to a battery fire but have had a good safety record in the years since.

Indian aviation authorities launched a broader review in the immediate aftermath of the crash and stepped up their oversight of the nation’s airlines. They found cases of improper maintenance procedures and a flight with worn tires. But they did not find any evidence of broader risks to Air India’s 787 fleet.

“This preliminary report answers some questions, but it poses other questions,” Guzzetti said.

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Brian Perlman contributed to this report.