TAIPEI, Taiwan — One of the engines on TransAsia Airways Flight 235 went idle 37 seconds after takeoff, and the pilots apparently shut off the other before making a futile attempt to restart it, Taiwan’s top aviation safety official said today.

The details were presented at a news conference in Taipei by Aviation Safety Council Executive Director Thomas Wang as preliminary findings from the flight data recorder.

Wednesday’s crash into a river in Taipei minutes after takeoff killed at least 35 people and left eight missing. Fifteen people were rescued with injuries after the accident, which was captured in a dramatic dashboard camera video that showed the ATR 72 propjet banking steeply and scraping a highway overpass before it hurtled into the Keelung River.

Wang said the plane’s right engine triggered an alarm 37 seconds after takeoff. However, he said the data showed it had not shut down, or “flamed out” as the pilot told the control tower, but rather moved into idle mode, with no change in the oil pressure.

Then, 46 seconds later, the left engine was shut down, apparently by one of the pilots, so that neither engine was producing any power. A restart was attempted, but the plane crashed just 72 seconds later.

Wang said it was too early to draw firm conclusions about the reasons why the first engine ceased producing power.

“It’s only the third day so we can’t say too much,” Wang said. “We haven’t ruled anything out.”