The twin-seat variation of the J-20 fighter jet, depicted by computer-generated imagery, is seen in a video released by AVIC celebrating the 10th anniversary of the aircraft's maiden flight in 2021

A twin-seat variation of China's J-20 stealth fighter jet and a J-20 version equipped with a domestically made engine have been spotted for the first time in official videos recently released by its developer and the People's Liberation Army (PLA) Air Force, only days before the 10th anniversary on Monday of the aircraft's maiden flight.

The twin-seat variation of the J-20 could be used for electronic warfare, command of wingman drones or bombing, and the domestic engine means the J-20 is no longer reliant on Russian engines, analysts said on Sunday.

Depicted by computer-generated imagery, four twin-seat J-20 variations were seen flying in formation in a video released by state-owned Aviation Industry Corp of China (AVIC), the developer of the aircraft, on Friday, in celebration of the 10th anniversary on Monday of the original aircraft's maiden flight.

This is the first time the twin-seat J-20 has been featured in an official promotional source, although media reports had speculated about its existence for years. It will also make the J-20 variation the world's first twin-seat stealth fighter jet, media reported.

By adding another seat to the cockpit, the aircraft could, in exchange for some level of stealth capability and manoeuvrability, carry a second pilot designated for more complicated tasks such as electronic warfare, command of wingman drones or tactical bombing, a Chinese military analyst told the Global Times on Sunday, requesting anonymity.

This means the twin-seat J-20 could spawn more variations that are equipped with devices corresponding to these tasks, the analyst predicted. 

AVIC's video did not elaborate on the twin-seat J-20 or its designed functions.

In a separate video, released on Tuesday by the People's Liberation Army (PLA) Air Force for its pilot recruitment program, Chinese media outlets identified a J-20 that is equipped with domestically developed WS-10C engines instead of imported Russian engines.

This is also the first time the PLA Air Force has confirmed that a J-20 equipped with a domestically made engine has entered service, Passion News, a media outlet under k618.cn, a news portal run by the Communist Youth League of China Central Committee, reported on Friday.

Designed with stealth capability, the WS-10C engines provide more powerful thrust than the Russian engines previously used on the J-20, since the Chinese engines use full authority digital engine control technology and improved afterburners, the Passion News report said.

Domestic engines will not only let the J-20 become stronger, but also enable the mass production of the aircraft without the limitation of imported engines, analysts said, noting that the J-20 will eventually use the WS-15, an even more powerful domestically developed engine.