On Tuesday, air safety experts raised concerns about the placement of an embankment at Muan International Airport, which a South Korean passenger jet collided with after skidding off the runway. The crash, which occurred on Sunday, resulted in the deadliest domestic air disaster in the country’s history, claiming the lives of all 175 passengers and four of the six crew members aboard the Jeju Air flight. The plane, which had belly-landed at the airport, crashed into a sand-and-concrete embankment and erupted into flames.

The investigation into the cause of the pilot’s decision to attempt the landing after declaring an emergency is ongoing. However, comments in the airport’s operating manual, released in early 2024, suggested that the embankment’s location was too close to the runway’s end and recommended a review of the site during the airport’s planned expansion.

A transport ministry official stated on Tuesday that authorities would need to examine the document before responding to inquiries. Experts criticized the embankment's placement, which housed navigation equipment. Captain Ross Aimer, CEO of Aero Consulting Experts, told Reuters, “Unfortunately, that thing was the reason that everybody got killed, because they literally hit a concrete structure. It shouldn’t have been there.”

Meanwhile, police continued efforts to identify the victims as family members waited anxiously at the airport for the release of their loved ones' bodies. The National Police Agency stated it was expediting the identification process, deploying additional personnel and rapid DNA testing to identify the remaining five unknown victims.

The investigation team also faced challenges with the Boeing 737-800’s flight data recorder, which was missing a crucial connector, though they have begun retrieving data from the cockpit voice recorder. Authorities expect to finish inspecting all 101 B737-800s operated by South Korean airlines by January 3, while the airport will remain closed until January 7.

Personnel from the U.S. National Transportation Safety Board (NTSB), Federal Aviation Administration (FAA), and Boeing have joined the investigation. Acting President Choi Sang-mok ordered an emergency safety inspection of the entire South Korean airline operation following the crash.

Investigators are exploring possible causes such as bird strikes or a malfunction in the plane's control systems that may have prompted the pilots to make a hasty landing after declaring an emergency. Transport Ministry officials noted that most South Korean airports were designed according to International Civil Aviation Organization (ICAO) guidelines, which recommend a 240-meter (262-yard) safety area at the end of runways. However, domestic regulations allow minor adjustments that do not “significantly affect” the facility’s performance.

The Muan International Airport Operations Manual indicated that the localizer equipment, a type of navigation aid, was positioned just 199 meters (218 yards) from the crash site, too close to the runway’s end. The manual recommended that the airport authority review the positioning of the equipment during the second phase of the airport's expansion.

While South Korean officials had previously stated that the structure was located about 250 meters (273 yards) from the runway, a paved apron extends beyond that point. However, experts like John Cox, CEO of Safety Operating Systems and a former 737 pilot, criticized the runway design, noting that industry standards typically keep hard structures like embankments at least 300 meters (330 yards) from the runway’s end. He also pointed out that video footage showed the plane appeared to be slowing down and under control before hitting the embankment, which he described as the turning point that led to the tragedy.

At Muan airport, both floors of the main terminal were crowded with grieving relatives, many of whom had gathered to pay their respects at a makeshift altar. Volunteers, religious, and social welfare groups provided food and drink to those waiting. Some family members sobbed as they took turns bowing before the altar, which was adorned with chrysanthemums and photos of the deceased. In the wake of the disaster, South Korea canceled New Year’s Eve celebrations nationwide, as the country mourned the loss.