Taiwan Air Force Plans NT$3.57 Billion Upgrade of Key Underground Base as China Threat Grows
Taiwan is preparing a major upgrade of one of its most important hardened air facilities, with the Air Force planning to spend NT$3.57 billion (about US$112.5 million) from 2027 to 2031 to modernize systems at Chiashan Air Force Base in Hualien.
The plan comes as Taiwan continues strengthening the survivability of its military forces against the possibility of missile and air attacks from China. The project was included in Taiwan's proposed 2027 defense budget submitted to the legislature.
Taiwan's underground fighter-jet shelter is getting a major overhaul
Built inside the mountains of Hualien, Chiashan is regarded as Taiwan's largest underground aircraft shelter.
The facility was completed in the early 1990s and is designed to protect aircraft and ammunition from bombardment and powerful earthquakes. It can reportedly accommodate around 250 fighter aircraft underground, making it a critical location for preserving Taiwan's air combat capability in the event of a first strike.
The underground complex is protected by Taiwan's Central Mountain Range, providing natural shielding from attacks originating from across the Taiwan Strait.
The War Zone previously reported that the facility consists of an extensive network of tunnels and hardened aircraft shelters and has been regarded as a key sanctuary for Taiwan's fighter fleet.
10 major systems will be upgraded
The NT$3.57 billion project will upgrade 10 major systems inside the facility, including:
- Instrumentation and control systems
- Ventilation and air conditioning
- Emergency power
- Elevators
- Security doors
- Fire protection
- Auxiliary facilities
- Electrical systems
- Water supply
- Drainage
The upgrades are also intended to improve the facility's protection against chemical, biological, radiological and nuclear threats, as well as electromagnetic pulses.
The Air Force says many of the existing systems have been operating for more than 30 years and are approaching the end of their service lives.
Another problem is what the military calls diminishing manufacturing sources and material shortages (DMSMS) — situations where original manufacturers stop producing components, suppliers leave the market or replacement parts become increasingly difficult to obtain.
Taiwan is also building more hardened aircraft shelters
The upgrade is only part of a much larger effort.
Taiwan's Air Force has separately budgeted approximately NT$6.88 billion between 2027 and 2031 to build 22 hardened aircraft shelters at Chiashan and four at Shizishan Air Base in Taitung.
The objective is to improve the protection of aircraft against bombardment and increase the chances that Taiwan's fighter force can survive an initial attack.
During wartime, Taiwan says its main fighter units would be dispersed between hardened facilities such as Chiashan and Shizishan to preserve combat capability.
Why Chiashan matters in a Taiwan-China conflict
Taiwan's air bases would likely be among the first targets in any major conflict across the Taiwan Strait.
China has developed a large arsenal of ballistic and cruise missiles capable of striking targets throughout Taiwan. That makes the ability to shelter aircraft underground particularly important.
The War Zone has previously described Chiashan as one of Taiwan's major protected aircraft facilities and noted that the base was designed to give the Air Force a better chance of surviving an initial wave of attacks.
The new upgrades suggest Taiwan is not simply expanding its aircraft fleet — it is also investing heavily in keeping those aircraft operational after an attack.
Another runway project is also planned
Taiwan's proposed defense budget also includes approximately NT$941.62 million from 2027 to 2032 for renovation of the main runway at Taichung's Ching Chuan Kang Air Base.
The Air Force says the dual-use airport project is intended to support emergency military operations while also maintaining peacetime aviation and civilian transport capabilities.
The bigger picture
Taiwan's latest spending reflects a broader shift in military planning: preparing not only for the weapons needed to fight, but also for the infrastructure required to survive the opening stages of a potential conflict.
Chiashan's mountain location, hardened shelters and planned upgrades could make it one of the most important facilities for Taiwan's air force in a crisis.
But the investment also highlights the seriousness of Taipei's assessment of the threat environment.
As China continues expanding its ability to strike Taiwan from the air, sea and land, the question is becoming increasingly urgent: Can Taiwan's hardened bases keep its fighter fleet alive long enough to fight back?