Most air forces protect their jets with concrete shelters on open ground. Taiwan went further. Between 1985 and 1993, according to English Wikipedia, the air force tunnelled into the hills west of Hualien’s runway to build the Chiashan complex, at a cost of more than NT$27 billion. The same account, citing the Taipei Times and Ian Easton’s reporting in The Diplomat, credits it with room for about 200 fighters, ten blast doors leading to the taxiways, an underground hospital and underground fuel stations. None of these figures has been published by the Ministry of National Defense, and they should be read as press estimates.

The logic is geography. Hualien sits on the east coast, with the Central Mountain Range between it and the Taiwan Strait, so aircraft sheltered here are harder to reach at the start of a conflict than those on the western plain. English Wikipedia calls Chiashan one of Taiwan’s most important defence installations because it houses the air force’s most survivable counter-attack forces; in 2018 the air force sought an automated close-in weapon system to defend it and Chihhang in Taitung.

The mountain is not the whole answer. In September 2026 the ministry announced 22 new hardened aircraft shelters and five transport hangars at Hualien, plus four shelters at Taitung, for NT$6.88 billion between 2027 and 2031, as reported by Taiwan News from the Liberty Times. The same report expects eastern Taiwan to hold 110–120 F-16Vs once the new Block 70s arrive at Chihhang.

The wing’s own history, published by the Air Force Command Headquarters, begins with the 5th Group formed at Jianqiao, Hangzhou, in 1936. It moved to Shuangliu in Sichuan in 1939 and to Zhijiang in Hunan in 1943 as part of the Chinese-American Composite Wing, claiming more than 120 Japanese aircraft shot down at a ratio of ten to one and more than 200 destroyed on the ground in a raid on Bailuo airfield. Those are the wing’s claims; Japanese figures were not checked.

The unit reached Taiwan in 1948, became the 5th Tactical Fighter Wing in 1953 and claimed its first MiG-15 on 15 October 1955 and 21 MiG-17s by the end of the 1958 strait crisis, again by its own count; the page does not say where it was based at the time. It was renamed the 5th Composite Wing in 1960 and the 401st Tactical Composite Wing in 1976, flying F-104s and F-5s.

In 1998 the wing left Taoyuan for Hualien and converted to the F-16A/B. Its groups were dissolved on 31 October 2004 and replaced by three combat squadrons. Under the Phoenix Rising upgrade its jets became F-16Vs with new radar and computers; the 100th converted aircraft landed at Hualien on 30 December 2022, and Taiwan News said upgraded jets would be based either at Hualien or at Chiayi.

Hualien was the last home of the Northrop F-5 in Taiwan. The first F-5A had arrived on 9 December 1965, AIDC completed the first locally built F-5E on 6 December 1974, and seven F-5Es were converted into RF-5E reconnaissance aircraft in 1997. On 4 July 2025 three RF-5Es and two F-5Fs flew over Hualien for the last time and taxied through a water salute; Colonel Hsu Chun-jung reported “RF-5E mission accomplished” to Vice Defence Minister Po Horng-huei. The RF-16 took over reconnaissance.

Fourteen months later the base opened a new chapter. General Atomics and air force personnel assembled Taiwan’s first two MQ-9B SkyGuardians at Hualien, and they began flight tests on 14 September 2026. Four drones and their ground stations cost NT$21.7 billion, funded from 2022 to 2029; the other two are due in 2027. Taiwan News described their job as long-range, all-weather surveillance of Chinese military movements around the Taiwan Strait.

Much of what the public sees of Hualien is exercise. During the Han Kuang 40 war games on 23 July 2024 President Lai Ching-te watched casualty-care drills at Hualien and runway-repair training at Chiashan. A year later, on 11 July 2025, the 5th Wing practised hot refuelling during Han Kuang 41, refuelling F-16s with their engines running so they could return to the air sooner.

The base has also hosted foreign pilots. From mid-October to 3 December 2024 six Mirage 2000-5s and two to three French pilots trained at Hsinchu and then Chiashan, where the 17th Squadron flew as the aggressor; Taiwan News put the annual cost of the Taiwan–France exchange at nearly NT$50 million. Nature intervenes too: in the magnitude 7.2 Hualien earthquake of April 2024, boarding ladders fell against F-16Vs at Chiashan, and the ministry said all repairs were complete and combat readiness was not affected.