*

Report cites signs of migratory ducks hitting both engines

*

No conclusion yet on go-around, sudden landing attempt

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Blackboxes stopped recording 4 minutes before deadly crash

(Writes through, updates with details of birds striking engines

in paragraph 15)

By Jack Kim

SEOUL, Jan 27 (Reuters) -

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.

The six-page report released by South Korean authorities

a month after the crash said both engines of the Boeing

737-800 jet contained DNA from Baikal Teals, a type of migratory

duck that flies to South Korea for winter in huge flocks.

But the report provided no initial conclusions about

what may have caused the plane to land without its landing gear

deployed, and why flight data recorders stopped recording in the

final four minutes of the flight.

The Jeju Air flight from Bangkok on Dec. 29 overshot

Muan Airport's runway as it made an emergency belly landing and

crashed into an embankment containing navigation equipment,

called localisers, killing all but two of the 181 people and

crew members on board.

"After the crash into the embankment, fire and a partial

explosion occurred. Both engines were buried in the embankment's

soil mound, and the fore fuselage scattered up to 30-200 meters

from the embankment," the report said, providing some new

pictures of the accident site.

The localiser aids navigation of an aircraft making an

approach to the runway, and the structure built of reinforced

concrete and earth at Muan airport supporting the system's

antennae likely contributed to the high death toll, experts have

said.

The investigation will tear down the engines, examine

components in depth, analyse in-flight and air traffic control

data, and investigate the embankment, localisers and evidence of

bird strike, the report said about its next steps.

"These all-out investigation activities aim to determine

the accurate cause of the accident," it said.

MAYDAY

The report highlighted much of the initial findings by

the South Korean investigators that were shared with victims'

families on Saturday, including the pilots' awareness of a flock

of birds on the plane's final approach.

The exact time the bird strike was reported by the pilots

remains unconfirmed, the accident report said, but the aircraft

"made an emergency declaration (Mayday x 3) for a bird strike

during a go-around."

The report does not say what may have led to the Cockpit

Voice Recorder (CVR) and Flight Data Recorder (FDR) to stop

recording simultaneously just before the pilots declared the

emergency.

The aircraft was at an altitude of 498 feet (152 metres)

flying at 161 knots (298 km/h or 185 mph) about 1.1 nautical

miles (2 km or 1.3 miles) from the runway at the moment the

flight recorders stopped recording, it said.

The International Civil Aviation Organization (ICAO), a U.N.

agency, requires accident investigators to produce a preliminary

report within 30 days of the accident and encourages a final

report to be made public within 12 months.

South Korea's Aviation and Railway Accident

Investigation Board has shared its report with ICAO, Thailand,

and the United States and France, which are the home states for

the plane and engine manufacturers, an official said on Monday.