Both engines of the TransAsia Airways ATR 72-600 aircraft, which crashed into a river in Taiwan Wednesday, had failed according to analysis of the flight data recorders, a Taiwanese official said Friday. Flight 235 crashed into the Keelung River near Taipei, killing 35 people, mostly Chinese tourists, headed to Kinmen islands off the coast of southeastern China.

Authorities claimed that one of the engines went idle 37 seconds after the plane took off from Taipei Songshan Airport. The Aviation Safety Council authorities announced at a news conference in Taipei that the pilot called "mayday" and announced an engine flameout 35 seconds after noticing an engine failure, according to Reuters. However, data showed that the engine had not shut down, or "flamed out," but rather went into idle mode, with no change in oil pressure, The Associated Press reported. 

Thomas Wang, the agency’s executive director, reportedly said that 46 seconds after the first engine became idle, the plane's left engine was shut down, apparently by one of the pilots, in a bid to restart both engines, but the attempt failed as the plane crashed just 72 seconds later.

Authorities reportedly said that the flight data recorders stopped recording one minute after the announcement of the flameout, which occurs when fuel supply to an engine is interrupted. However, Wang also reportedly said that it was too early to conclude why the engines may have lost power.

"It's only the third day so we can't say too much," Wang said, according to AP. "We haven't ruled anything out."

The twin-engine, turbo-prop aircraft, which was carrying 53 passengers and five crew members on board, was reportedly less than a year old but one of its engines had been replaced last April, after authorities discovered a problem with the original engine, the airline said, according to AP.