Y-12 transport aircraft assigned to an air transport brigade under the PLA airborne troops take off in sequence during a joint transportation training exercise that involves multiple types of transport aircraft on May 21, 2021. (eng.chinamil.com.cn/Photo by Li Zhuojun)

The defense authority on the island of Taiwan on Tuesday confirmed that a Chinese mainland civilian aircraft recently approached Dongyin Island, a Taiwan-occupied island not far from the Chinese mainland, and Taiwan side speculated that the Chinese mainland was testing Taiwan's response measures. 

However, Chinese mainland experts said on Wednesday that the incident only exposed the Taiwan military's weak air defense capability, and such a flight could become routine or even expand to include larger areas if Taiwan secessionists continue to provoke.

The aircraft that was spotted near Dongyin on February 5 was a Chinese mainland civilian Y-12 light twin-engine aircraft, Huang Chih-wei, head of Taiwan's aerial armed force, said at a press conference on Tuesday, media on the island of Taiwan reported.

Shih Shun-wen, a spokesperson at Taiwan's defense authority, said at the press conference that it was possible that the Chinese mainland was "using the civilian aircraft to test Taiwan's response measures."

While Taiwan's defense authority claimed it was prepared and had taken measures to monitor the aircraft, it was local residents who first reported the incident as they filmed the aircraft, and the Taiwan military reacted only after that, exposing Taiwan's weak air defense capability, Fu Qianshao, a Chinese mainland military aviation expert, told the Global Times on Wednesday.

Taiwan's defense authority failed to provide a flight route for the Y-12, despite it normally publishes the flight routes of Chinese mainland aircraft that have entered Taiwan's self-proclaimed air defense identification zone, media on the island pointed out.

Dongyin is part of the Matsu Islands and less than 50 kilometers east of the Chinese mainland's Fujian Province, and about 185 kilometers northwest of Keelung on Taiwan island, media reports said. This means it is much closer to the Chinese mainland than to the island of Taiwan.

The incident could be caused by a navigational deviation of the Y-12, since Dongyin is so close to the Chinese mainland, Fu said, noting that Dongyin is an inalienable part of China, so this is not an issue at all.

It could also be intentional, since the Y-12 can also carry equipment for surveillance and monitoring, Fu said. "In this case, it is a strong warning to the Taiwan secessionists."

In response to the repeated provocations by forces seeking "Taiwan independence,"  Chinese mainland analysts have suggested that the Chinese People's Liberation Army (PLA) could fly over the island of Taiwan in addition to holding drills near the island should the secessionist moves escalate.

The latest incident indicates that a flyover of Taiwan-occupied outer islands by mainland aircraft, civilian or military, could serve as an effective measure to deter Taiwan secessionists, Fu said, noting that if Taiwan secessionists still insist on provocation, this flyover could eventually expand to the island of Taiwan itself.

It is worth observing if the latest incident is only occasional or will become routine, Fu said.