A preliminary report by India's Aircraft Accident Investigation Bureau reveals that a cut in the fuel supply to the engines caused last month's Air India Boeing 787-8 Dreamliner crash that claimed 260 lives, reports CNN.
According to the report, the fuel control switches in the cockpit of the Boeing 787 Dreamliner had been flipped, starving the engines of fuel.
Investigators were able to get data out of the plane's "black box" recorders, including 49 hours of flight data and two hours of cockpit audio, including from the crash.
The aircraft had reached an airspeed of 180 knots when both engines' fuel cutoff switches were "transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec," the report reads.
"In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so," it adds.
Shortly after, the switches were reversed back to where they should have been, and the engines were in the process of powering back up when the crash happened.
On the 787, the fuel cutoff switches are between the two pilots' seats, immediately behind the plane's throttle levers. They are protected on the sides by a metal bar and have a locking mechanism designed to prevent accidental cutoff. Airport footage shows the Ram Air Turbine, an emergency power source on an aircraft, deployed during the plane's initial climb after takeoff, the report said. The plane started to lose altitude before crossing the airport perimeter wall.
"When fuel control switches are moved from CUTOFF to RUN while the aircraft is in flight, each engine's full authority dual engine control automatically manages a relight and thrust recovery sequence of ignition and fuel introduction," the report states.
Seconds after the engines attempted to relight, one pilot called out, "MAYDAY MAYDAY MAYDAY." The controller called out for the plane's callsign, but didn't get a response and watched the plane crash in the distance.
The fuel switches were "designed to be intentionally moved," according to CNN safety analyst David Soucie, who said cases in which all fuel switches were turned off accidentally are "extremely rare."
"Throughout the years, those switches have been improved to make sure that they cannot be accidentally moved and that they're not automatic. They don't move themselves in any manner," Soucie said on Friday.
Investigators also noted settings on the equipment found in the wreckage were normal for takeoff. The plane's fuel was tested and found to be of satisfactory quality, and no significant bird activity was observed in the vicinity of the flight path, according to the report.
The takeoff weight for the plane was found to be within allowable limits, and there were no "Dangerous Goods" on the aircraft. Investigators found the flaps on the wings of the plane were set in the 5-degree position, which is correct for takeoff, and the landing gear lever was in the down position.
The left engine was installed on the plane on March 26, and the right was installed on May 1, the report stated.
Comments