In the plane’s cockpit voice recording, one pilot was heard asking the other why the fuel switches were turned off.
A preliminary investigation into the June 12 Air India plane crash, which killed 260 people on board and on the ground, found that the flight’s fuel control switches were cut off just seconds after takeoff.
Flight AI171, a Boeing 787 bound for London, was carrying 242 people on board when it crashed into a residential area shortly after takeoff. All but one person on board were killed, and 19 others on the ground died when the plane struck a medical college hostel. The sole survivor escaped through a broken emergency exit and sustained minor injuries.
The investigative report by India’s Aircraft Accident Investigation Bureau (AAIB) on July 11 found that the fuel control switches for both engines of the flight “transitioned from run to cutoff position one after another with a time gap of 01 [second].”
Both engines then began to lose power from their takeoff levels as the fuel supply to the engines was cut off, the report stated.
In the plane’s cockpit voice recording, one pilot was heard asking the other why he had cut off the fuel switches, to which the copilot responded that “he did not do so,” according to the report.
Airport surveillance footage showed that the Ram Air Turbine—a small turbine on aircraft that serves as an alternate power source—was deployed during the plane’s initial climb just after takeoff. Flight AI171 began losing altitude before it crossed the airport perimeter wall, the report said.
“When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control automatically manages a relight and thrust recovery sequence of ignition and fuel introduction,” it stated.
Both engines showed signs of relighting, but one failed to arrest core speed deceleration. One of the pilots transmitted “Mayday, Mayday, Mayday” before the plane crashed outside the airport boundary, according to the report.
AAIB stated that it was still reviewing the evidence and “at this stage of investigation, there are no recommended actions to Boeing 787-8 and/or GE GEnx-1B engine operators and manufacturers.”
