Aviation experts have raised questions about an “unusual” concrete wall near the runway and its role in the South Korean plane crash that killed 179 people.
Footage shows a Jeju Air plane leaving the runway before crashing into a wall and bursting into flames at Muan International Airport.
Authorities investigating the cause of South Korea’s worst plane crash are considering the significance of the concrete wall’s location about 250 m (820 ft) from the end of the runway.
Aviation safety expert David Learmount said that had the “obstruction” not been there, the plane “would have been left with most – perhaps all – of those still alive”.
The pilot reported that the aircraft struck a bird and then aborted the initial landing and requested clearance to land from the opposite direction.
The aircraft descended some distance along the 2,800 meter runway and appeared to land without the use of wheels or any other landing gear.
Mr Learmount said the landing was “as good as a flapless/gearless touchdown can be: wings level, nose not too high to break the tail” and that the plane suffered no significant damage as it slid along the runway.
“The reason for the death of so many people is not the landing as such, but the fact that the plane collided with a very solid obstacle just beyond the end of the runway,” he said.
Christian Beckert, a Lufthansa pilot based in Munich, called the concrete structure “unusual”, telling the Reuters news agency: “Normally, at an airport with a runway at the end, you don’t have a wall.”
The concrete structure holds a navigation system that helps the plane land – known as a localizer – according to South Korea’s Yonhap news agency.
It is 4 meters tall, covered with earth and raised to bring the localizer level with the runway to ensure its proper functioning, Yonhap reported.
South Korea’s transport ministry said other airports in the country and some overseas have equipment built into concrete structures. However, officials will investigate whether it should have been made of lighter materials that would break more easily on impact.
Chris Kingswood, a 48-year-old pilot who flew the same type of aircraft involved in the crash, told BBC News: “Obstacles within a certain range and distance from the runway have to be frangible, meaning that if the aircraft hits them they break.
“It seems unusual that it’s such a rigid thing. The plane, I understand, was traveling very fast, it landed a long way down the runway, so it must have gone well off the end of the runway… so where do you draw the line with that? It’s definitely something to look into.
“Airplanes are not strong structures – they are, by design, light to be efficient in flight. They are not really designed to fly at high speed on their belly, so any structure can cause the fuselage to crack and then be catastrophic.
“Fuel is trapped in the wings, so when a wing breaks, then the potential for fire is significant.
“So it’s not certain that it would have been a completely different outcome if the wall hadn’t been there.”
Mr Kingswood said he would be “surprised if the airport did not meet all requirements to industry standards”.
“I imagine that if we were to go round the airfields at many of the major international airports … we would find a lot of obstacles that could similarly be accused of being dangerous,” he added.
Aviation analyst Sally Gethin questioned whether the pilot knew the barrier was there, especially since the plane was approaching from the opposite direction of the normal landing approach.
She told BBC News: “We need to know are they (pilots) aware that there is this hard boundary at the end?
“If they were ordered by the control tower to change the use of the runway a second time, that should come out in the black box investigation.
“I think there are so many questions.”
