A New Look at the World’s First Twin Seat Fifth Gen. Fighter: China’s J-20AS Progressing Towards Joining the Fleet

Following its unveiling in October 2021, the world’s first twin seat stealth fighter developed by China’s Chengdu Aircraft Industry Group has been widely reported to be moving towards entry into service in the Chinese People’s Liberation Army Air Force. The name of the new aircraft remains uncertain, with both J-20S and J-20AS having been used to refer to it, although the latter appears more likely considering that it is based on the airframe of the J-20A which replaced the original in production in mid-2019. The main differences are use of the indigenous WS-10C engines to replace the Russian AL-31FM2, providing greater reliability and a supercruise capability, as well as reductions to the aircraft’s radar cross section and various improvements to avionics. The twin seat variant not expected to be primarily used as a trainer, but rather to accommodate weapons systems officers for roles such as drone control, command and control and operation of air to ground weapons. 

While the J-20’s direct American analogue the F-22 was initially planned to be developed into a twin seat variant, with F-22B prototypes ordered and a bomber fighter variant also considered as the FB-22, these programs were cancelled. Production of the fighter was then prematurely terminated in 2011 as a result of its extremely high maintenance needs and operational costs as well as wide ranging performance issues. Where the U.S. was unable to develop the F-22 further, ambitious plans for the J-20 are already taking the design well ahead of its rivals including development of both strike and electronic attack derivatives which will likely use the twin seater as a basis for development. The J-20 is currently being produced at a far greater rate than any twin engine fifth generation fighter ever has, and likely ever will, with the cancelled F-22 and low production rate Su-57 both falling far behind leaving the F-35 as its only near peer level competitor. The two stealth fighters, which are the only ones in the world currently both in production and fielded at squadron level strength, saw their first encounter confirmed in March 2022, and are effectively in a league of their own in terms of sophistication among fighter aircraft. The F-35’s smaller size has made development of a twin seater unfeasible, however, and unlike the J-20 ongoing performance issues have prevented it from being approved for full scale production.