The preliminary report was released by the Aviation and Railway Accident Investigation Board on Monday in South Korea.

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

Traces of bird strikes were found in the engines of the Jeju Air flight that crashed at Muan International Airport, killing all but two of the 181 passengers. The preliminary report identified remains of migratory ducks.