*

Experts say many questions yet to be answered

*

They see it as unlikely that a bird strike would cause

landing

gear malfunction

*

Jeju Air says only that investigation is underway

*

Deputy transport minister says runway length not a

contributing

factor

(Adds comments from transport ministry, Jeju Air, background on

how the investigation will proceed)

By Bart Meijer

Dec 29 (Reuters) - Uncertainties surround the deadliest

crash on South Korean soil, experts said on Sunday, questioning

initial suggestions that a bird strike might have brought down

the Jeju Air flight.

The apparent absence of landing gear, the timing of the

twin-engine Boeing 737-800's belly-landing at Muan

International Airport and the reports of a possible bird strike

all raised questions that could not yet be answered.

The single-aisle aircraft was seen in video broadcast on

local media skidding down the runway with no visible landing

gear before slamming into a wall in an explosion of flame and

debris.

"Why didn't fire tenders lay foam on the runway? Why weren't

they in attendance when the plane touched down? And why did the

aircraft touch down so far down the runway? And why was there a

brick wall at the end of the runway?" said Airline News editor

Geoffrey Thomas.

South Korean officials said they were investigating the

cause of the crash of Jeju Air Flight 7C2216, including a

possible bird strike. The crash killed 179 of the 181 people on

board.

A spokesperson for Jeju Air was not immediately available

for comments. Jeju Air declined to comment on the cause of the

accident during news conferences, saying an investigation is

under way.

Under global aviation rules, South Korea will lead a civil

investigation into the crash and automatically involve the

National Transportation Safety Board in the United States where

the plane was designed and built.

The flight data recorder was found at 11:30 a.m. (0230 GMT),

about two and a half hours after the crash, and the cockpit

voice recorder was found at 2:24 p.m., according to South

Korea's transport ministry.

"That gives you all the parameters of all the systems of the

plane. The heartbeat of the airplane is on the flight data

recorder," Thomas said. "The voice recorder will probably

provide the most interesting analysis of what went on on this

tragic crash."

Experts caution that air accidents are usually caused by a

cocktail of factors and it can take months to piece together the

sequence of events in and outside the plane.

CHAIN OF EVENTS

In the space of a few minutes, the control tower issued a

bird strike warning, pilots declared mayday and then attempted

to land, officials said, although it was not clear whether the

aircraft had hit any birds.

Experts said it seemed unlikely a bird strike would have

caused the landing gear to malfunction.

"A bird strike is not unusual, problems with an

undercarriage are not unusual. Bird strikes happen far more

often, but typically they don't cause the loss of an airplane by

themselves," Thomas said.

Australian airline safety expert Geoffrey Dell said, "I've

never seen a bird strike prevent the landing gear from being

extended."

Australian aviation consultant Trevor Jensen said fire and

emergency services would normally be ready for a belly-landing,

"so this appears to be unplanned".

A bird strike could have impacted the CFM International

engines if a flock had been sucked into them, but that would not

have shut them down straightaway, giving the pilots some time to

deal with the situation, Dell said.

It was unclear why the plane did not decelerate after it hit

the runway, Dell and Jensen said.

Typically in a belly-landing, "You are going to land on your

engines and you're going to have a bumpy ride," Thomas said.

"You come in with minimum fuel, you have fire tenders in

attendance, covering the runway with foam and you land at the

furthest end of the runway and usually it ends up being an OK

situation."

After the control tower issued the bird strike warning and

the pilots declared mayday, the pilots attempted to land on the

runway from the opposite direction, a transport ministry

official said.

"In the process of landing it hit a navigation safety

facility called a localizer and collided with the wall," the

official said.

Joo Jong-wan, deputy transport minister, said the runway's

2,800-metre length was not a contributing factor, and that the

walls at the ends had been built according to standards.

"Both ends of the runway have safety zones with green buffer

areas before reaching the outer wall," he told a separate

briefing. "The airport is designed according to standard

aviation safety guidelines, even if the wall may appear closer

than it actually is."

The captain had worked at that rank since 2019 and had

logged 6,823 flight hours, the ministry said. The first officer

had worked at that rank since 2023 and had logged approximately

1,650 flight hours.

The Boeing ( BA ) model involved in the crash, a 737-800, is one of

the world's most flown airliners with a generally strong safety

record and was developed well before the MAX variant involved in

a recent Boeing ( BA ) safety crisis.