As the mound-type localizer is pointed to as a cause that exacerbated the damage in the Jeju Air passenger plane accident at Muan International Airport in South Jeolla Province, responsibility is expected to differ based on who decided to construct the facility and when. A fierce debate is anticipated, involving related parties such as the Ministry of Land, Infrastructure and Transport, Korea Airports Corporation, Muan Airport, and the design and construction companies.
On the 3rd, the Ministry of Land, Infrastructure and Transport announced regarding the localizer facility's upper concrete reinforcement work at Muan Airport, 'The improvement project service designer proposed it, and Korea Airports Corporation accepted it.' It was explained that the design firm at that time devised the concrete mound reinforcement as a stabilization measure for the localizer support, and the construction was carried out as proposed.
A localizer is an antenna that assists with aircraft landings. At the accident site, Muan Airport constructed a 2-meter-high concrete structure and installed the localizer. They piled earth around the concrete structure to form it into a hill shape.
After the accident, the Ministry of Land, Infrastructure and Transport initially explained that the facility was in compliance with regulations, but later shifted their stance, stating that they would further review the relevant regulations as safety concerns grew.
According to Article 109, Paragraph 5 of the current airport safety operation standards, facilities intended for navigation within 240 meters of the end of the landing strip should be frangible and installed as low as possible.
However, at Muan Airport's runway direction 19 (north to south), the localizer is installed 199 meters from the end of the landing strip, which is 41 meters shorter than the 240-meter standard.
Additionally, the material itself lacks ease of breakability. The localizer and the antenna exposed to the ground are made of frangible material, but the supporting foundation is a concrete structure covered with soil. Last year, an improvement project added a 30 cm-thick concrete upper plate over the mound. This project added a concrete upper plate 40 meters long, 4.4 meters wide, and 30 cm high on the mound.
There is a debate over whether the mound facility of the localizer ensured 'frangibility' from the initial setup or if the improvement work with the additional concrete upper plate last year was a decisive factor that increased the disaster's damage.
A Ministry of Land, Infrastructure and Transport official explained that this concrete upper plate was installed to prevent facilities related to the localizer on the mound from shaking. The official noted, 'When the localizer was initially installed, the concrete pillar and soil were filled to the top, and there was exposed concrete at the end. Using it in such a form for 15 years caused the soil structure to sink and equipment to vibrate due to exposure to wind and rain.'
There is still no clear explanation regarding the background of the upper plate installation at that time. The initial design work order included reviewing the frangibility of the antenna and metal rail parts, but there was no mention of adding a concrete upper plate.
A Ministry of Land, Infrastructure and Transport official explained that, apart from the work order, the designer proposed the upper plate addition to prevent shaking, and Korea Airports Corporation accepted it.
It was revealed that the designer who participated in last year’s localizer improvement work at Muan Airport also participated in the concrete mound design at Yeosu Airport.
The Ministry of Land, Infrastructure and Transport stated that they have yet to identify the selection process and method for the design firm and need to verify specific facts regarding the localizer based on the design documents and related materials.
The Ministry of Land, Infrastructure and Transport will conduct a special inspection of the installation locations and materials of navigation safety facilities around runways at airports nationwide until the 8th. If the risk of the mound-type localizer facilities is confirmed following the inspection, improvement work is expected to proceed.