[Yang Nak-gyu's Defence Club] Military Aircraft Life Extended by 40 Years... Flying in from Hawaii Too

Korean Air, Responsible for Overhaul and Maintenance of US Military Aircraft for 40 Years
Maintained 437 F4 Fighter Jets Over 35 Years

Korean Air began mass production of the '500MD military helicopter' in 1976, the first of its kind in Korea, marking the beginning of the domestic complete aircraft production era. It subsequently produced and supplied the 'F-5 Freedom Fighter' and 'UH-60 medium helicopter' domestically to the military. Korean Air also ventured into unmanned aerial vehicle (UAV) development. In 2014, Korean Air developed the UAV 'Gaori-X1.' Using Gaori-X1, it plans to collaborate with the Agency for Defense Development (ADD) to develop 'unmanned swarm aircraft' and 'stealth unmanned reconnaissance aircraft.'

Last month, to get a glimpse of Korean Air's aviation technology, I visited the Korean Air Tech Center located at Gimhae Airport, where several military aircraft were visible at a glance from the entrance.

Since 1983, Korean Air has been responsible for depot-level maintenance of military aircraft used by the U.S. military. Depot-level maintenance involves completely disassembling the airframe of military aircraft after a certain flight time, inspecting various parts, and repairing or replacing any detected defects. The goal is to maintain the aircraft in a condition equivalent to a new military aircraft. The U.S. military entrusts Korean Air’s Aerospace Business Division in Busan with aircraft maintenance, receiving aircraft from locations such as Hawaii, Okinawa, and Alaska.

The military aircraft at the Korean Air Tech Center, which spans a total area of 710,000 square meters (210,000 pyeong), had their original paint stripped off, revealing a silver color, making it difficult to identify their nationality. However, even with wings and some parts removed, the distinctive shapes of each military aircraft model were preserved. The aircraft undergoing maintenance at the front of the maintenance line was the F-15 fighter jet, which is also a mainstay fighter for the South Korean military. The inscription ‘84-0012’ on the aircraft served as its identification. ‘84’ indicates the production year, and ‘0012’ denotes the unit number produced that year. The F-15 undergoes depot-level maintenance after six years of operation. Depending on the condition of the airframe, the maintenance period can take up to 10 months. Except for the main frame, the entire airframe is disassembled. Critical disassembled parts are repaired or replaced after X-ray inspection. Since the aircraft is reassembled afterward, the process is more complex than manufacturing a new fighter jet.

The Korean Air Tech Center is considered the largest military aircraft maintenance base in the Asia-Pacific region. A Korean Air official stated, “The F-4 fighter jets, which were retired last year, underwent depot-level maintenance for a total of 437 units over 35 years since 1988,” adding, “The reason the U.S. military entrusts us with maintenance of their F-4, F-15, F-16, C130, A-10, and other aircraft is precisely because of our technology and know-how.”

Next to the F-15 fighter jet were about ten F-16 fighter jets of the U.S. Forces Japan, which had flown in from Japan, lined up. The F-16s were undergoing life extension work. The main frame, resembling human ribs, was also replaced with new parts. Through this process, the F-16’s lifespan (8,000 flight hours) is extended by approximately 4,000 hours. Unlike the South Korean military, the U.S. military typically extends flight hours through performance upgrades.

The A-10 (Thunderbolt II) anti-tank attack aircraft was also under maintenance. With increasing threats from North Korea’s mobile missile launchers (TEL) and armored ground forces, the U.S. Forces Korea decided to operate the A-10 attack aircraft for an additional 10 years. Originally scheduled for retirement in 2020, it is now planned to be used until 2030. Korean Air played a role in the U.S. decision to extend the A-10’s service life. The wings of the A-10 tend to crack or develop scratches after about 8,000 flight hours. However, Korean Air participated in the wing upgrade work and successfully completed depot-level maintenance. The A-10 equipped with new wings completed flight tests at Hill Air Force Base in Utah in 2020 and was recognized for its performance.

In June 2019, after meeting with North Korean Supreme Leader Kim Jong-un at Panmunjom, U.S. President Donald Trump visited Osan Air Base and expressed his intention to continue operating the A-10, highlighting it as a key weapon of the U.S. Forces Korea. At that time, President Trump referred to the A-10 as the fierce ‘Warthog,’ a nickname inspired by the aircraft’s low-altitude charge while emitting white smoke and firing its gatling gun, which attracted considerable attention.

On the adjacent line, not only fighter jets but also helicopter depot-level maintenance was in full swing. The CH-53 heavy helicopter operated by the U.S. military was present. Although all seven main rotor blades (the helicopter’s top propellers) had been removed, its massive body remained visible. The front of the aircraft was covered with densely packed schedules for each task, such as electrical and electronic work (blue) and sheet metal work (green). The maintenance pace was coordinated by crossing off tasks according to color-coded schedules. Korean Air has been responsible for depot-level maintenance of the CH-53 heavy helicopter from 1989 to 2010 for over 20 years and was reselected as the maintenance contractor for the CH-53 heavy helicopter operated by the U.S. Marines in 2015. This reflects the U.S. military’s recognition of Korean Air’s maintenance capabilities.

After completing all depot-level maintenance work, U.S. military aircraft undergo about two months of ground performance testing. Subsequently, the U.S. military personnel visit to conduct test flights themselves before flying the aircraft back to their bases.