J-15 fighter jets commence takeoffs from the aircraft carrier Shandong. Photo: Courtesy of Ding Zheng

The Shandong aircraft carrier group of the Chinese People's Liberation Army (PLA) reportedly returned to the south via the Taiwan Straits on Monday following a month-long operation in the north, with experts saying on Tuesday that the Shandong likely helped train pilots for another PLA aircraft carrier, the north-based Liaoning, which has been under routine maintenance.

The armed forces on the island of Taiwan detected the PLA Navy Shandong aircraft carrier fleet heading south along the Taiwan Straits steering along the west side of the so-called median line, the defense authority on the island said in a press release on Monday evening.

It marked the Shandong's return to the South China Sea after it was spotted sailing north through the Taiwan Straits a little more than a month ago on November 9, after the aircraft carrier had just wrapped up a record-breaking far sea exercise in the West Pacific.

When asked about the Shandong's northward transit in the Taiwan Straits without returning to its homeport in South China's Hainan Province after its far sea exercise in the Pacific Ocean, Senior Colonel Zhang Xiaogang, a spokesperson at China's Ministry of National Defense, said on November 16 that the PLA Navy organized exercises in relevant waters to hone and enhance the Shandong aircraft carrier groups' systematic combat capabilities.

The drills are a regular arrangement made based on an annual training schedule that conforms to international law and practices, Zhang said, noting that the Chinese military holds similar training activities on a routine basis.

A video published by China Central Television on Thursday shows that the Shandong hosted full-process takeoff and landing exercises for J-15 fighter jets at an undisclosed location in November.

During the Shandong's one-month voyage in the north, the carrier probably operated in the Bohai Sea and the Yellow Sea to help train pilots of the PLA Navy aircraft carrier Liaoning, which is based in the north but has been under routine maintenance since February, observers said, citing media reports.

Song Zhongping, a Chinese military expert and TV commentator, told the Global Times on Tuesday that fighter jet takeoff and landing operations are basically the same on the Liaoning and the Shandong, so when the Liaoning is under maintenance, it is normal that the Shandong can train pilots and crews for the Liaoning.

It also highlights the merits of having multiple aircraft carriers, experts said.

While the defense authority on the island of Taiwan is certain to be nervous about them, the PLA carrier's transits in the Taiwan Straits are not likely targeted at the island, analysts said, explaining that the Taiwan Straits is just the shortest route that links southern and northern waters off the Chinese coast, and in a possible scenario of a conflict, the Taiwan Straits is too narrow for aircraft carriers to play any significant role.

But the increasing combat capabilities of PLA aircraft carriers are surely significant in deterring "Taiwan independence" secessionist forces and external interference forces, Song said.