Regarding the 'mound localizer', which is identified as a cause for intensifying the damage scale of the Jeju Air passenger plane accident at Muan International Airport, the Ministry of Land, Infrastructure and Transport noted, 'After reviewing the accident investigation results, we will consider (changing the structural form).' Currently, similar mound localizer structures are installed at Pohang Gyeongju Airport, Cheongju Airport, and Yeosu Airport domestically. There are no clear safety regulations regarding building mounds to install localizers. If the relevant regulations are made in light of this accident, it is anticipated it will become another 'safety rule revision written with blood' in aviation history.
Joo Jong-wan, Deputy Minister of the Ministry of Land, Infrastructure and Transport, responded to an inquiry about the 'plan to replace mound-structured localizers' during a briefing on the Muan Airport accident held on the afternoon of the 31st at the Ministry's pressroom in the Government Complex Sejong, stating, 'It is difficult to reveal the decision to replace mound-structured facilities at this moment,' and added, 'We will review it after checking the accident investigation results.' Deputy Minister Joo added, 'The accident investigation committee will investigate whether the mound of the localizer increased the accident damage,' and 'We are keeping various possibilities open while proceeding with the investigation, being cautious of focusing on any specific issue as the cause of the accident.'
◇ 'It cannot function properly if localizer is lower than runway'... reason for piling up a 2m mound
At Muan International Airport, there is a localizer installed at a height of 2 meters on a mound 199 meters from the end of runway 19 (north to south). A localizer refers to an antenna-type facility installed around an airport runway designed to emit signals to guide aircraft for a central landing on the runway.
Muan Airport built the runway by leveling the ground and subsequently filling it. Beyond the runway's end, it transitions into a gentle downhill slope. This structure is suitable for reducing airport construction expense and facilitating runway drainage. The elevation difference between the 199-meter mark where the localizer is installed and the runway is approximately 2 meters. The airport opted to pile a mound to match the heights of the runway surface and the localizer.
A Ministry of Land, Infrastructure and Transport official stated, 'If the localizer is lower than the runway, it could experience interference while transmitting signals to the aircraft,' adding, 'The antenna was raised considering the angle of the signals.'
In the case of Incheon Airport, a core domestic airport, the localizer is installed in a form protruding about 7.5 cm like a parking stopper at the 295-meter point from the end of the runway. The localizer antenna is designed with a soft steel structure to prevent aircraft damage in case of collision.
Regarding criticisms that this mound-like localizer installation violates aviation regulations, the Ministry of Land, Infrastructure and Transport has not yet provided a clear answer. Concerning indications made the previous day that the mound at Muan Airport violated detailed guidelines for the management of aviation obstacles stating 'equipment or installations placed within airport premises must be mounted on easily breakable supports,' the Ministry clarified, 'The mentioned regulation does not apply to equipment or obstacles installed outside the end-safety area.' However, during the briefing, they stepped back, stating, 'We will verify the regulations precisely.'
It was confirmed through CHOSUNBIZ research that Muan Airport had previously been criticized for not meeting recommended standards for the endpoint safety zone regarding the localizer installation point. In response, an official from the Ministry of Land, Infrastructure and Transport stated, 'We will comprehensively examine both relevant regulations and past criticisms.'
◇ 'Transition to stacking steel structures instead of dangerous mounds needed'
According to Article 109 of the Airport Safety Operation Standards, navigation equipment or facilities to be installed in the non-stop zone of a landing area are considered obstacles. It is stipulated that such facilities must be installed as low and easily breakable as possible.
The Ministry of Land, Infrastructure and Transport's ordinance for detailed guidelines on aviation obstacle management also stipulates that localizers and similar installations 'must be mounted on easily breakable supports.' The U.S. Federal Aviation Administration stipulates that localizer facilities must be constructed as easily breakable structures as well.
The Ministry of Land, Infrastructure and Transport has yet to provide a clear answer as to whether mounds should be regarded as 'related facilities.' In response to a question asking whether a localizer mound should be seen as part of the bearing facility, an official stated, 'It should be viewed as a support structure.'
An aviation industry official stated, 'A localizer must be constructed so that aircraft can pass through easily in case of an over-run beyond the runway,' adding, 'Raising a steel structure may appear suitable if the elevation at the localizer installation point is lower than the runway.'