Since the J-20 saw its first flight in 2011, there has been significant speculation from a wide range of sources as to the Chinese fifth generation heavy fighter’s purpose and what specific role it was assigned to fulfil. The aircraft’s size, twin engines, stealth profile and airframe all indicated an air superiority role similar to the U.S. F-22 Raptor, which entered service in 2005, though a number of alternative theories have also prevailed. While a large airframe, high thrust, operational altitude and speed, long range and sizeable missile payload are all key to the performance of the F-22 and other air superiority platforms such as the Russian Su-35 and Chinese J-11B, a number of combat roles other than engaging the elite of an enemy’s fighter fleet also require such specifications.
A number of analysts speculated that the J-20 was designed not as an air superiority fighter like the F-22, but rather as an interceptor similar to the Russian MiG-31 Foxhound - a successor to the J-8 currently in service in China’s own air fleet. Such fighters are extremely heavy, with the MiG-31 today remaining the heaviest combat aircraft in the world other than heavy bombers, deploy extremely heavy payloads carrying large missiles such as the R-33 and Kh-47M2 which fighter aircraft would struggle to deploy, and travel at very high speeds. The two fastest combat aircraft ever developed, the MiG-25 and MiG-31, were both designed as interceptors. While the J-20 is heavy by the standards of fighters, it remains significantly lighter than the MiG-31 and lacks the platform’s massive missile payload. The Chinese fighter’s high manoeuvrability, which has improved markedly since deploying new WS-15 engines, and incorporation of thrust vectoring technologies, also strongly indicate an air superiority role rather than being focused solely on long range air to air engagements. With interceptors designed exclusively for combat at extreme ranges, they remain the least manoeuvrable of all aircraft deigned for air to air combat. As more details regarding the J-20’s capabilities have been revealed, it has become clearer that its capabilities are not suited to the role of a dedicated interceptor.
Another role considered a possibility for the J-20 was that of an interdictor or strike fighter, similar to the FB-22 concept variant of the F-22 Raptor or the Russian Su-34. Such fighter would require a longer range than even air superiority fighters, and their primary task would be offensive actions to destroy enemy infrastructure and disrupt their war effort as an interdictor or to target enemy ground and possibly naval surface platforms at long ranges as a strike fighter. The J-20’s stealth capabilities and high operational altitudes could well have made it an invaluable platform for such a role, but the fighter’s airframe appeared to more closely reflect an intended air superiority role. The vast maritime distances separating China from its major potential adversaries, and Beijing’s already formidable and ever expanding maritime strike capabilities, also indicate that Beijing needs to modernise its air superiority capabilities far more than it does its air to ground strike capabilities - with a number of other programs already allocated to this offensive task. Indeed, controlling the skies above the South and East China Seas is set to be key to determining the outcome of a potential future conflict should Chinese interests in these regions come under attack by the United State and its allies.
Speculation regarding the J-20’s purpose has likely finally been put to rest due to a recent report by the Chinese state media outlet People’s Daily, an official newspaper of the Chinese Communist Party (CCP) which extensively covers military affairs. The report released on June 2nd 2018, covering recent exercises carried out by a new generation of China’s most advanced fighters including the J-20, J-10C single engine light multirole fighter and J-16 strike fighter, stated the role assigned to each of these platforms. The report stated: “During the exercise, the J-20 pilots used their aircraft's advantages in terms of situational awareness and stealth to gain air superiority, while the J-16 and J-10c fighters carried out precision strikes on ground targets. The training sought to take full advantage of the different capabilities of the fighter jets.” With China fielding by far the largest air superiority fleet in the world, it is only fitting that its first fifth generation platform should be a fighter designed modernise the country's capabilities in the field.
With the J-20 confirmed to be specialised in an air superiority role, complementary to those of China’s other new combat aircraft, the elite platform is a direct competitor to the Untied States Air Force’s F-22 Raptor - a fighter which the J-20 is expected to surpass in its capabilities in the near future due to the far greater pace at which it is being enhanced and the stagnation in the Raptor program since the termination of production in 2009. While the J-20 will fulfil an air superiority role, remaining outstanding questions regarding China’s fifth generation fighter programs include the role of the upcoming J-31 (interceptor or multirole fighter), the potential existence of further unannounced fifth generation programs, and the future of the J-20 as a potential carrier based fighter or possible development of another fifth generation airframe for carrier based air superiority operations. With air superiority being highly prized, and China one of just three countries alongside Russian and the United States capable of producing high end air superiority fighters, the J-20 remains a key asset to the People’s Liberation Army’s military modernisation and is likely to become the leading platform of its kind in the fifth generation.