Aviation experts have raised questions about an “unusual” concrete wall near the runway and its role in the plane crash in South Korea that killed 179 people.

Footage shows the Jeju Air plane skidding off the runway at Muan International Airport on Sunday before colliding with the wall and bursting into flames.

Authorities investigating the cause of South Korea’s worst ever plane crash are considering the significance of the concrete wall’s location about 250 meters (820 feet) from the end of the runway.

Aviation safety expert David Learmount said that if the “obstacle” had not been there, the plane “would have come to a standstill with most – possibly all – of the occupants on board still alive.”

The pilot reported that the aircraft hit a bird and subsequently aborted the original landing, and requested permission to land from the opposite direction.

The plane landed a short distance down the 2,800 m long runway and appeared to land without using its wheels or any other landing gear.

Mr Learmount said the landing was “as good as a flap/gearless landing can be: wings level, nose not too high to avoid tail breakage” and the aircraft gliding along the runway suffered no significant damage.

“The reason why so many people died was not the landing as such, but the fact that the plane collided with a very hard obstacle just beyond the end of the runway,” he said.

Another aviation analyst agreed. Captain Ross Aimer, managing director of Aero Consulting Experts, told Reuters: “Unfortunately this thing was the reason everyone was killed because they literally crashed into a concrete structure. It shouldn’t have been there.”

Christian Beckert, a Munich-based Lufthansa pilot, called the concrete structure “unusual” and said: “Normally at an airport with a runway you don’t have a wall at the end.”

According to the South Korean news agency Yonhap, the concrete structure contains a navigation system that supports the landing of aircraft – a so-called localizer.

At a height of 4 m, it is covered with earth and has been raised to keep the scope level with the runway and ensure that it functions properly, Yonhap reported.

South Korea’s transport ministry said equipment with concrete structures had been installed at other airports in the country and some abroad. But officials will examine whether it should have been made from lighter materials that would break more easily on impact.

Chris Kingswood, a pilot with 48 years’ experience who flew the same type of aircraft involved in the crash, told BBC News: “Obstacles within a certain range and distance from the runway must be fragile, which means an aircraft. “They notice that they are breaking.

“It seems unusual for it to be such a rigid thing. From what I understand, the plane was flying very fast and landed way down on the runway, so it will have flown well past the end of the runway…” So where will you draw the line? This will certainly be investigated.

“Airplanes are not strong structures – they are inherently light to make them efficient in flight. They aren’t really designed to fly on their stomachs at high speeds, so any type of structure could cause the fuselage to break and then be destroyed catastrophically.

“The fuel remains in the wings, so the risk of a fire is significant once the wing breaks.

“It is therefore not a given that without the wall the result would have been completely different.”

Mr Kingswood said he would be “surprised if the airfield had not met all the requirements in line with industry standards”.

“I suspect if we were to go around the airfields of many major international airports we would find many obstacles that could also be classified as dangerous,” he added.

But former pilot John Cox, managing director of Safety Operating Systems, said the runway design was “absolutely not” consistent with industry best practices, which exclude any hard structure within at least 300 m (984 feet) of the end of the runway.

After the crash, it emerged that Muan International Airport’s operations manual, uploaded in early 2024, contained a note indicating that the concrete embankment was too close to the end of the runway.

In the case of Korea Airports Corp. The document recommended that the location of the equipment be reviewed as part of a planned expansion.

South Korea’s director general of airport policy, Kim Hong-rak, said the government would “review the relevant regulations and their application.”

Aviation analyst Sally Gethin questioned whether the pilot knew the barrier was there, particularly given the plane was coming from the opposite direction to the usual landing approach.

She told BBC News: “We need to know, were (the pilots) aware that there was this hard limit at the end?”

“If they were instructed by the control tower to reverse the use of the runway the second time, that should come to light when examining the black boxes.”

“I think there are so many questions.”

At a press conference on Tuesday, Jeju Air chief Kim Yi-bae was unenthusiastic when asked about the concrete wall.

When asked by a reporter whether he believed the wall was a factor in the disaster, he did not give a direct answer and instead said it was correct to call the plane crash a Jeju Air disaster rather than a Muan Air disaster.