No Safety Issues with 1,200m Runway at Ulleung Airport

SUM Air Co., Ltd. (CEO: Yong-Duk Choi) announced on the 27th that following a site visit to Yoron Airport, located on Yoron Island north of Okinawa, Japan—which features a 1,200-meter runway similar to Ulleung Airport—it was confirmed that there are no safety concerns for ATR72-600 aircraft operations on a 1,200-meter runway.

During the visit, the team boarded an ATR72-600 aircraft operated by JAC (a subsidiary of Japan Airlines), the same model SUM Air plans to introduce. The aircraft took off smoothly from Kagoshima Airport. Contrary to expectations of high noise levels due to its propeller design, the aircraft was surprisingly quiet during the flight. After about an hour, the aircraft landed safely at Yoron Airport. Even after vacating the runway to enter the ramp area, a significant portion of the runway remained unused, highlighting the ample length of the 1,200-meter runway.

Recently, there has been public concern over the safety of Ulleung Airport’s 1,200-meter runway, especially in light of the recent incident at Muan Airport. However, the ATR72-600 model, which SUM Air plans to operate, meets the requirements of the European Union Aviation Safety Agency (EASA) under the Multiple Maximum Takeoff Weight (MTOW) certification, qualifying it for 2C category operations. This allows for a takeoff distance of 1,031 meters and landing distance of 660 meters, demonstrating that 1,200 meters is more than sufficient for safe operations.

A representative from JAC commented, “The ATR72-600 is well-suited for island operations with strong winds. It continues to operate safely even in typhoon-level conditions.”

The ATR72-600 has a demonstrated crosswind limit of 35 knots, which is 5 knots higher than the 30-knot limit of Boeing 737s, the current mainstay for many airlines. This makes it even safer for the strong wind conditions typical of Ulleung Island.

When asked about the need for proper airport facilities for an island prone to rain and fog, a Yoron Airport official stated, “For enhanced safety during aircraft operations, the installation of precision instrument approach systems is a better solution than relying solely on visual flight.”

Ulleung Airport is currently being constructed as a 3C Visual Flight Rules (VFR) airport, following the June 10, 2024 amendment to the Aviation Business Act, which raised the seat limit for small air transport businesses to 80 seats. Previously, it was designed as a 2C Instrument Flight Rules (IFR) airport.

However, due to the rapidly changing weather conditions on Ulleung Island, operating as a VFR airport raises concerns about flight safety and a higher cancellation rate, potentially affecting airport viability. There is growing support for equipping the airport with Instrument Landing System (ILS) facilities to ensure safer operations and reduce cancellation rates. According to a technical proposal by Daelim E&C, the airport’s main contractor, conversion to an IFR airport could reduce the cancellation rate from 26% to 8.7%.

Ulleung Airport is expected to become a design benchmark for future small airports such as Heuksan and Baengnyeong. Given this, there is a strong case for re-discussing the decision to build it as a 2C IFR airport to avoid unnecessary spending and delays while improving safety and reliability.

[Attachment] Construction Strategy for Ulleung Airport: Improving Safety and Reducing Cancellations

1. Design Revisions of Ulleung Airport

   1. In the 2013 master plan, the airport was initially designed as a 2C VFR airport for 50-seat aircraft such as the ATR-42 and Q-400.

      1. 2C VFR: Runway (1,100m x 30m), Runway Strip (60m x 80m)

   2. In 2021, due to safety and cancellation concerns, the design was upgraded to 2C IFR.

      1. 2C IFR: Runway (1,200m x 30m), Runway Strip Width (80 → 140m)

      2. Cancellation rate (Daelim Technical Proposal): VFR – 26%, IFR – 8.7%

   3. In 2024, following a legal revision and aircraft supply trends, plans were made to reclassify the airport as 3C VFR to accommodate 80-seat ATR72 aircraft.

      1. Design change: Classification upgraded from 2C to 3C, Runway Strip Width (140 → 150m)

      2. Revised Aviation Business Act: Max seats raised from 50 to 80

2. Need for Precision Approach (ILS) Facilities

   
   

If operated under VFR conditions, flights can only proceed when visibility exceeds 5 km and cloud ceiling is above 450 m. According to the 2013 preliminary feasibility study (p.105), the cancellation rate was estimated at 18.1% using FAA criteria (300m cloud ceiling), and likely higher in real-world scenarios. The Daelim technical report projects a 26% cancellation rate for VFR vs. 7.8% for IFR, matching the historical ferry cancellation rate (26%).

Operating as a 3C VFR airport could severely impact residents’ and travelers’ access, raising questions about the airport’s effectiveness and potentially turning it into a deficit-running facility. Thus, construction as a 2C IFR airport is essential.

3. Challenges of Implementing ILS

Ulleung Airport is currently under construction as a 3C VFR airport. Converting it to a 3C IFR airport poses several challenges:

1. Runway Strip Expansion

   To qualify as a 3C IFR airport, the strip must be widened to 280m. Given the island’s steep coastal terrain, this would require massive additional funding and long delays. Technical feasibility is uncertain due to steep underwater topography.

   
   

2. Limited Benefits

   Even if the expansion is achieved, the 1,200m runway cannot accommodate typical 3C aircraft. The classification upgrade would yield little benefit, as the runway barely exceeds the 2C limit. Moreover, VFR-only operations would still limit safety and flight reliability, rendering the upgrade unjustifiable.

   
   

4. Proposed Solutions

   
   

Airports are vital infrastructure that support transportation, economic activity, and quality of life. Ulleung Airport, the first of its kind for island regions, is expected to serve not just Ulleung-gun but the broader Daegu-Gyeongbuk region.

However, downgrading the airport’s operational capacity due to regional characteristics could hinder economic revitalization. To ensure stable operation and economic contribution, it must be built as an IFR airport. The following solutions address the issues:

1. Apply Multiple MTOW (Maximum Takeoff Weight)

   The ATR72-600 can be operated as a 2C aircraft by applying Weight Variant 10, reducing its MTOW to 22 tons. In this configuration, it requires only 1,031m for takeoff—well within the 1,200m runway. This eliminates the need for additional funding or delays. Multiple MTOW is already applied by major airlines, including Korean Air.

   
   

2. Install Displaced Thresholds

   By constructing 60m displaced thresholds at both ends of the runway, the Takeoff Run Available (TORA) can be increased to 1,320m, and the Landing Distance Available (LDA) to 1,260m. This improves both safety and operability.

   
   

3. Runway Grooving

   Ulleung Island experiences frequent rain and snow—over 201 days per year on average. Wet or slippery runways reduce braking efficiency, increasing landing distance and risk. Grooving the runway surface enhances friction and operational safety.

Conclusion

Ulleung Airport must be constructed as a 2C IFR airport by applying the above solutions. This approach ensures compatibility with the expanded seat capacity policy for small air transport, without additional budget or delays. It secures sustainable air access to Ulleung Island and supports national aviation policy, regional economic development, and residents’ rights to air travel—laying the foundation for a new era of accessible regional aviation.