Jeju Air Flight 2216 did not have to end in such a catastrophe.
Early on Dec. 29, a clear Sunday morning, the Boeing 737-800 made an emergency landing on its belly at South Korea’s Muan International Airport. The aircraft skidded past the end of the runway, smashed into a concrete structure and burst into flames. Of the 181 passengers and crew members aboard, 179 were killed.
Runway excursions — when an aircraft overruns or veers off the runway during landing or takeoff — have for years been among the most common type of aviation accident. But in the vast majority of cases, the planes come safely to a stop, saved in part by zones around runways that are supposed to contain only structures that are frangible, meaning designed to break easily upon impact.
The New York Times analyzed information on more than 500 runway excursions and found that 41 resulted in deaths. In 2010, 158 people died when a flight in India overran the runway and fell into a gorge. But no other runway excursion has come close to the death toll at Muan airport, according to the data, which was compiled by the nonprofit Flight Safety Foundation.
Accidents in which planes hit breakable structures at the end of runways have tended not to be deadly:
The story behind why a steel-reinforced concrete structure stood so close to a runway illustrates a longstanding vulnerability in global air transport. A United Nations aviation safety agency issues recommendations to keep the area near airport runways clear of obstacles. But it is up to national regulators and private companies that manage airports to interpret, implement and oversee compliance of those standards.
Inquiries by The Times to airport regulators in more than two dozen countries revealed inconsistencies in how they interpret the standards issued by the U.N. agency, the International Civil Aviation Organization.
Since the Jeju Air crash, international aviation groups have urged airport operators to examine the areas surrounding runways, and a number of countries have conducted inspections.
In South Korea, authorities found safety violations at seven of the country’s 14 airports, with structures that could damage planes that overshoot or veer off a runway.
Safety analysts say such accidents don’t have to result in disaster.
“Runway overruns do happen, and happen often,” said Hassan Shahidi, the president of the Flight Safety Foundation, based in Alexandria, Va. “That’s why the safety of the area around the runway is so crucial, and why the presence of concrete barriers in these areas must be carefully investigated.”
On Wednesday, the South Korean government said it would replace concrete and other hard structures housing navigation equipment with “easy-to-break lightweight steel,” completing the work at Muan airport by the end of August and at other airports by the end of the year.
More than four months since the crash, authorities continue to investigate what caused the Jeju Air flight’s emergency landing. Preliminary findings suggest that a bird strike as the plane approached the airport caused the pilots to lose control. It remains unclear why the plane’s landing gear failed to deploy, or why its wing flaps didn’t appear to engage — limiting the pilots’ ability to slow the plane down.
But experts interviewed by The Times widely agreed that the concrete structure near the end of the runway played a catastrophic role in the accident’s deadly outcome.
The International Civil Aviation Organization, or I.C.A.O., recommends that airports have “runway end safety areas.” In those zones, all structures, such as the one at issue in the South Korean crash, should be designed to break easily upon impact.
At Muan, a relatively small airport in the southwest part of the country, the structure was a mount for an antenna array that provides radio guidance to aircraft coming in for a landing. These arrays, known as localizers, are commonly installed near airport runways.
In 2020, renovation work on Muan’s localizer mount was authorized by the Korea Airports Corporation, a state-owned entity that oversees the country’s airports, and was completed in early 2024. The work included adding a thick concrete slab running along the mount, atop an earthen berm. The berm covered concrete pillars supporting the antenna.
Air safety regulators outside South Korea said the localizer might have been placed atop the berm to ensure a strong signal. The concrete base may have been designed to protect the localizer from harsh weather, such as snow or typhoons. But several of them said they were shocked that local authorities would have approved the construction of such a structure.
In January, the former president of the airports corporation, who was in office during the renovations at Muan International Airport, died in what the local police called an apparent suicide.
Local experts said in interviews that the country’s regulations, based on I.C.A.O. standards on runway safety areas, were highly ambiguous.
In South Korea, a law known as the Airport Facilities Act provides the framework for airport safety standards. It was drawn in part from recommendations by the I.C.A.O. but lacks specificity on issues like how to build barriers near runways that break upon impact, said Hyoseok Chang, an assistant professor at Hanseo University’s department of air transportation and logistics.
“It is difficult to find specific details on the required strength levels or exact structural specifications” for localizer mounts, Mr. Chang said. “There is no regulation in Korea explicitly stating that concrete cannot be used,” he added.
In the immediate aftermath of the Jeju Air crash, South Korean officials stated that the antenna mount at Muan airport, about 866 feet from the runway’s end, complied with safety regulations. But in the days that followed, they acknowledged that they needed to review the barrier’s placement and design.
The Korea Airports Corporation announced in early April that it had officially commenced improvement work at the seven airports where navigation aids were not installed according to safety standards, with plans to give the improvements at Muan first priority.
Disastrous runway overrun accidents like the one at Muan airport have, in the past, spurred regulatory changes.
In the United States, the Federal Aviation Administration strengthened safety standards for areas surrounding runways after an American Airlines plane landing in Arkansas in 1999 ran into a stanchion just off the runway that tore through the plane, killing 11 people.
For most large airports in the United States, the F.A.A. recommends that any structures within 1,000 feet of the runway’s end be frangible. The United Nations’ I.C.A.O. recommends a minimum safety area of either 295 or 787 feet based on factors including the length of the runway.
The Flight Safety Foundation’s database, which has complete information on accidents that caused injuries, deaths or significant damage to aircraft over the last 15 years, includes hundreds of examples illustrating how runway overruns can produce far less catastrophic outcomes.
In October 2022, Korean Air Flight 631 overran the runway at Mactan-Cebu International Airport in the Philippines. Amid heavy rain, the Airbus A330-322 skidded off the runway and struck a localizer mount. The plane continued through the structure before coming to a stop more than 700 feet from the runway’s end. All 173 passengers and crew members survived, and the metal structure on which the localizer was mounted was found wrapped around the plane’s wings.
The severity of any aviation accident is determined by its own set of often complex circumstances, and potential airport hazards, such as steep drop-offs at the end of runways, make it difficult to precisely compare accidents.
After the Jeju Air disaster, some countries have investigated the safety of localizer structures at airports. Japanese officials confirmed that localizer structures near runways were sufficiently frangible. In Taiwan, the airport regulator said it would soon implement similar checks across its airports.
Other groups are waiting to see the results from an ongoing investigation into the Jeju Air crash.
Regulators including the Civil Aviation Authority in Britain said they would closely examine the crash investigation for any lessons they should follow at their airports. The I.C.A.O. said in a statement that while carrying out its standards was solely up to sovereign authorities, the results of investigations like the one in South Korea informed ongoing reviews of its technical standards.
In South Korea, government officials have said they would spend about $178 million over the next three years fixing issues including the problematic localizer structures at the country’s airports. The authorities said on Wednesday that all airports would now be required to meet the I.C.A.O. standards for a safety area extending at least 787 feet. Airports with limited space must install materials called Engineered Material Arresting Systems, which can slow or stop planes that careen off the runway, they said.
Sangdo Kim, a former South Korean deputy minister for civil aviation who served as ambassador to the I.C.A.O., urged international regulators to learn from the Jeju Air crash.
“Many lives were lost in the Muan crisis,” Mr. Kim said. “To prevent similar accidents, all countries should voluntarily inspect their localizer-housing structures.”
In an ideal world, regulators would enforce consistent safety standards at airports worldwide, Mr. Kim said. But in reality, larger international airports often receive priority for safety checks over smaller, less visited ones like Muan, he said.
