Jeju Air Plane Crash Highlights Decades of Blunders and Deadly Runway Wall

The call came on a December morning while Lee Jun-hwa, an architect from Seoul, was overseas on a business trip.

“I think Mom is dead,” his younger brother told him.

A plane returning from Thailand had crashed at an airport in Muan, in southwest Korea, and their mother’s name was on a list of passengers.

Mr. Lee watched footage of the explosion, again and again, unable to accept that these were his mother’s last moments.

The slabs formed part of a structure housing crucial navigation antennas that help pilots find the runway when visibility is low. International safety guidelines say such structures should be made of material that breaks apart easily if a plane collides with them.

That was not the case in Muan.

A New York Times investigation found a series of design and construction failures that allowed the wall to be built with concrete and put too close to the runway, in violation of international safety guidelines. It also found that the government ignored a stark warning about the safety risks.

Since the crash, as The Times investigated what went wrong, Mr. Lee has conducted his own inquiry. As a relative of one of the crash’s victims, he gained access to documents and shared them with The Times. Reporters independently reviewed the documents, unearthed more, and spoke to experts.

The blunders started with a design change years before the airport opened in 2007. The original plans drawn up in 1999, and obtained by The Times, envisaged breakable foundations to anchor the antennas, known as localizers, on both ends of the runway. But at some point the design changed, and the private companies hired to build the airport used concrete.

The error was compounded when a government ministry approved the construction even though it was warned by officials that the localizers were too close to the runway. The structures’ height and material composition did not meet international standards, either.

Then, years later, regulators approved renovation works that added even more concrete to one of the walls, rendering it harder to break.

Multiple factors led to the crash. The plane was hit by birds as it neared the airport — investigators found feathers in both engines — and the pilots may have shut down an engine that sustained lesser damage than the other. But The Times has found that the solid wall at the end of the runway most likely made the accident deadlier than it would have been otherwise.

“In a way, you could say what they did was insane,” Mr. Lee said.

“There is a cause for the accident and a separate cause for the deaths,” he said.

The Times obtained blueprints from the airport’s initial construction and the latest renovation and asked five experts to review them. Reporters also combed through documents issued by Korean authorities over the last 26 years.

The solid wall was not the only problem that was ignored at Muan Airport. The authorities were repeatedly warned about the airport’s proximity to bird habitats, which increased the risk of bird strikes at landing and takeoff.

Multiple investigations into the cause of the accident — the worst on South Korean soil — are underway and some inquiries have focused on the concrete structure. The authorities found solid structures close to runways at six other airports across Korea. South Korea’s government vowed to fix the problems before the end of the year. (All of the runways besides that at Muan’s airport have stayed open.)

Mr. Lee, like other relatives of the crash victims, is frustrated by the slow slog toward accountability. He carries on, determined to answer an overwhelming question.

“Who did this?”

Baffling Design Change

As he floated in a fog of grief after the crash, the concrete structure — solid, unyielding and misplaced — haunted Mr. Lee.

He spent sleepless nights compiling a dossier of local laws on airline and airport operations. He pored over accident reports for other plane crashes. He took pictures and measurements of the concrete structure. He consulted experts.

His quest, he says, is to relieve the families’ “han,” a Korean term for deep sorrow and rage.

“If I keep all of this bottled up,” Mr. Lee said, “it will turn into something heavy, like a lump.”

Though he grew up in a nearby city, Mr. Lee had barely visited Muan before the crash. It is a farming county with a strong scent of manure and an onion for a mascot.

In a twist of fate, it was another tragedy that changed the county’s trajectory. After a passenger plane crashed at a nearby airport in 1993 and killed 68 people, local and national lawmakers decided to build a new airport in Muan. They hoped to make Muan a regional transport hub.

The central government’s Ministry of Land, Infrastructure and Transport, then known by a different name, approved the airport’s development and drew up its basic design in the late 1990s.

A consortium of four contractors led by Kumho Engineering & Construction won the contract to build the airport. The design was assigned to five other Korean companies. Construction work, overseen by regional aviation administrators who were in turn supervised by the ministry, began in 1999.

The original master plan, which The Times shared with experts, stipulated the localizers would be built on breakable foundations to “minimize fatal damage to an aircraft in the event of a collision.” The designs aligned with international standards.

Engineers told The Times that concrete is cheaper than more easily breakable timber and steel structures. The contractors also did not level the sloped ground beyond the runway, which experts said would have been costly.

“Somewhere in the process, the right decision just didn’t get made,” Mr. Lee said.

Kumho Engineering & Construction, the Korean firm that led the consortium, did not respond to questions. One company involved in the design, HJ Shipbuilding & Construction, said that it was “unable to locate relevant personnel or documentation” because the project was too old. Other companies involved in the design and construction did not answer questions on the rationale behind the changes.

Documents show that government regulators knew about the safety risks. Most airports in the country are run by the Korea Airports Corporation, a state-owned entity under the transport ministry, which was set to take over the management and operation of Muan Airport when it opened. In May 2007, six months before the opening, the Corporation sent the transport ministry a report that carried a stark warning: The localizer structures were too close to the runway.

But in its official reply, the ministry sidestepped the warning. A few months later, it issued a certificate allowing the airport to open on the condition that improvements would be made later. Over the following decade, the ministry did not mention the issue during multiple annual inspections.

National regulators like the ministry have wide discretion to interpret and enforce international standards. The I.C.A.O. said that it could not comment on the “exclusive sovereign responsibility of specific states.”

The transport ministry did not answer questions about the design changes, citing an ongoing police investigation.

In 2020, the ministry squandered a major opportunity to fix the safety issues with the localizer. By South Korean law, airport navigation systems have to be refurbished every 14 years. But the design company responsible for the renovation, Anse Technologies, stacked another solid structure — a thick, reinforced concrete slab — on top of the existing foundation.

Once again, regulators approved the design, and the project was completed in February 2024, 10 months before the crash. No attempts were made to move the wall farther from the runway.

To Mr. Lee, this was tantamount to “an act of murder.”

Anse Technologies oversaw the design of localizer structures at four Korean airports including Muan, according to its website. Officials subsequently found safety problems at two of the runways — a localizer was anchored to a mound at one airport and a second localizer was installed too close to the runway at another. The company did not respond to questions.

The ministry told The Times that the concrete slab was installed to “ensure signal stability” and prevent the localizer from “shaking or sinking due to wind and rain.”

In December of last year, the Muan airport ramped up daily international flights operated by low-cost carriers after a long pandemic lull. Its passenger numbers tripled in just a month as many Koreans, including Mr. Lee’s mother, started traveling again. The terminal came to life and regional leaders celebrated with a ribbon-cutting ceremony. The airport was finally becoming the hub they had long envisioned.

Later that month, disaster struck.

Families’ Anger

After the crash, Mr. Lee’s brother, a medical doctor, handled the immediate aftermath of the crash in Muan, where relatives waited to receive the remains of their loved ones and held vigils. Their mother’s body was discovered in pieces — 12 parts in all — which were identified by DNA tests.

Mr. Lee joined other bereaved families demanding answers. But, by late April, they were increasingly at odds with local authorities.

Officials wanted to reopen the airport. The ministry said that it would replace the wall with a breakable steel structure by this month and fix problems at the other airports by the end of the year.

But the victims’ families wanted to keep the airport shut until the end of the investigations. Some wanted to build a monument from the crumbled pieces of the wall, a reminder of what should not have happened. Others worried that blame could hastily be assigned to the former president of the airports corporation, who died in January in what the police said was a suicide.

Then, word came that investigators were planning to dig out the foundation wall. Worried that evidence could be destroyed, the families rushed to the airport.

Mr. Lee drove down from Seoul to observe the excavation. At the airport, he stood with other families, drenched in an apocalyptic downpour. They closely watched a yellow excavator as it scooped out dirt and exposed the concrete pillars underneath. Some families stepped over police tape for a closer look.

Back in the shelter of the terminal, people sketched out drawings of the wall and asked Mr. Lee questions. Over months, he had become the go-to expert and a voice for bereaved families at official briefings.

In May, relatives of the victims filed a complaint with the police demanding the prosecution of people they accused of negligence and violating South Korean law. Those named included the former minister of transport, a former official from the airports corporation and the chief executives of Jeju Air, the carrier, and Anse Technologies, the company responsible for the renovation design.

The police have since said they are investigating 24 people, including government officials, on suspicion of professional negligence that resulted in death or injury. The officials under investigation were not named but the police said they were responsible for “air traffic operations, bird strike prevention and airport facility management.”

One independent review by the Computational Structural Engineering Institute of Korea will assess the potential impact of an aircraft’s collision with the wall. The board investigating the crash commissioned the review and the results could be released as soon as this month.

Mr. Lee still frets that the investigations may never reach conclusive findings. He is determined to identify the responsible parties before the physical evidence vanishes and only paperwork is left behind.

“Even without the slab, an explosion still might have happened,” Mr. Lee said. “But without it, I feel like there could have been at least some chance of survival.”