South Korea’s authorities investigating last month’s Jeju Air plane crash have submitted a preliminary accident report to the UN aviation agency and to the authorities of the United States, France and Thailand,

Investigators say they have found evidence of a bird strike on a passenger plane that crashed in South Korea in December and killed 179 people. The feathers and blood stains on both engines of the Jeju Air plane were from the Baikal teal,

Pilots’ actions after the bird strike are an early focus of the investigation, according to people familiar with the probe.