Taipei, Taiwan – As the investigation into the deadly crash of Jeju Air Flight 2216 enters its third day, aviation experts are raising questions about what role a concrete structure at the end of the runway at South Korea’s Muan International Airport may have played in the crash, among other things. . the factors.
The Boeing 737-800 slammed into a concrete embankment and burst into flames after being forced to make an emergency landing on Sunday morning, killing 179 of the 181 people on board in the deadliest plane crash on South Korean soil.
The pilot had reported a bird strike to air traffic control moments before the plane belly-flopped onto the runway after failing to deploy its landing gear and overshooting the landing zone.
South Korean authorities have said the concrete embankment, which housed a localizer antenna to help pilots maintain the correct approach path, was built according to regulations and was similar to other structures at airports around the world.
However, some aviation experts have questioned the choice and placement of the structure, suggesting that the disaster could have been avoided with better airport design.
Najmedin Meshkati, a professor of civil engineering at the University of Southern California, said the use of concrete instead of installing a metal tower or pole was “unusual” and may have contributed to the high death toll.
“This rigid structure proved disastrous when the glider made an impact,” Meshkati told Al Jazeera.
“Undoubtedly, if the plane had hit the airfield wall, which would have had less resistance, the survival rate might have been higher.”
Hassan Shahidi, president and CEO of the Aviation Safety Foundation, said that while he would not speculate whether the embankment was poorly designed or positioned, the structures at the end of the runway must be built to break easily in the event of a crash under International Civil Aviation. Organizational guidelines.
“The standards also specify the proximity of such structures near the ends of the runway. Investigators will examine the concrete structure at the end of the runway to determine if it complies with these standards, including its placement and proximity to the end of the runway,” Shahidi told Al Jazeera.
South Korean officials have said the structure was 250 meters from the end of the runway, closer than the best practice standard of 300 meters, according to John Cox, a former 737 pilot who runs aviation consultancy Safety Operating Systems.
Experts also questioned whether the runway had an adequate rollover zone or, as in the case of other airports with limited space, should have implemented an “engineered material containment system” – also known as “EMAS” – capable of slowing down or stopping an aircraft. with excessive vigor.
Dane Williams, director of consultancy Aviation Safety Asia, said some advanced airports have areas behind the runway that use sand, gravel or another decelerating substance to reduce an aircraft’s speed and avoid a hard impact.
“In more developed countries, such mitigation is put at the bottom of the tracks where it is credible, where it is convenient and where it is economically viable,” Williams told Al Jazeera.
“It is also understandable, however, that if a large lake, river or other geophysical location such as a valley is at the end of the runway, then a concrete physical barrier may be appropriate.”
Other airport design features are also under consideration.
Marco Chan, a pilot and senior lecturer in aviation operations at Buckinghamshire New University, said the choice of a runway with a -0.2 per cent downward slope raised “further questions about its suitability for an emergency landing”.
“Investigators will look into whether this decision affected the weather conditions, which were calm… or whether other operational considerations influenced it,” Chan told Al Jazeera.
South Korean investigators, assisted by officials from the United States’ National Transportation Safety Board, are looking into a number of possible scenarios, including a bird strike and failure of the aircraft’s systems.
Preliminary findings on the cause of the disaster are not likely to emerge for weeks. It is possible that some or all of the theories raised by officials and analysts will not be confirmed by the investigation.
“When you’re doing an investigation, you don’t just look at the plane. You look at the human element, which means you look at the pilots, you look at air traffic control, you look at maintenance, then you look at the machine,” Anthony Brickhouse, a veteran US-based aerospace safety expert, told Al Jazeera.
“What happened to that plane that prevented them from lowering the landing gear?”
While bird strikes have been blamed for contributing to a number of air crashes, including the deadly crash of Ethiopian Airlines Flight 302 in 2019, a bird strike by itself is unlikely to bring down a modern airliner, according to aviation experts.
More than 13,000 bird strikes are reported to ICAO each year, only a small fraction of which result in aircraft damage or flight interruption.
In the case of Flight 2216, investigators will examine whether a bird may have damaged critical systems, such as engines and hydraulics, leading to “cascading failures, including hydraulic problems or the inability to deploy the landing gear,” Chan said. .
Analysts have been particularly puzzled by the speed at which the plane landed and its failure to deploy its landing gear.
Video footage of the disaster also showed that the plane’s nose never fully lowered before the plane went off-frame and exploded.
“Video footage suggests the aircraft was approaching at a relatively high speed, raising questions about whether the aircraft was properly configured for landing or whether system failures prevented the main deceleration mechanisms from operating,” Chan said.
Brickhouse said it was also apparent from footage of the crash that the plane had landed in some way below the runway.
“On a landing, friction will be your friend in slowing you down. “Unfortunately, it doesn’t appear that the plane was on the runway long enough to slow down,” Brickhouse said.
South Korea’s transport ministry said on Tuesday that the “black box” flight recorder was recovered from the crash site with key parts missing and authorities were looking into how to retrieve the data.
The National Police Agency said it was deploying more personnel and using rapid DNA analysis to speed up identification of the crash victims as family members gathered at the airport to seek more information about their loved ones.
South Korea’s acting president Choi Sang-mok has ordered an emergency safety inspection of all the country’s airline operations, while authorities are separately conducting inspections of all Boeing 737-800s in operation in the country.
