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

The exact cause of the Jeju Air crash remains unclear, and the investigation is complicated because the black boxes stopped recording four minutes before impact.

The feathers and blood stains on both engines of the Jeju Air plane were from the Baikal teal, a type of migratory duck that flies in large flocks, according to a preliminary investigation report published on Monday.

South Korea released a preliminary report into last month’s deadly Jeju Air Co. crash that offers more detail on the role of bird strikes in the disaster, while still leaving crucial questions unanswered.

Authorities have suggested that migratory bird strikes were the cause of last month's deadly plane crash in South Korea, according to multiple reports.

South Korean officials investigating the fatal Jeju Air crash have published a preliminary report of the accident.

The first report on last month’s Jeju Air crash in South Korea has confirmed bird strikes in the plane’s engines, though officials haven’t determined the cause of the accident that killed all but two of the 181 people on board.

Both engines of the Jeju Air plane that crashed last month contained duck remains, according to a preliminary report on Monday, with authorities still trying to determine what caused the deadliest air disaster on South Korean soil. Julian Satterthwaite reports.

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,

Seoul: The South Korean transport ministry on Saturday has revealed that the ill-fated Jeju Air flight, involved in last month’s deadly crash, received a warning from air traffic control about potential bird activity just one minute before its black box recording stopped.

South Korean authorities have submitted a preliminary report on last month's fatal Jeju Air crash to the International Civil Aviation Organization. The ongoing investigation focuses on a 'bird impact' as well as examining the aircraft's engines and landing systems.