China’s first fifth-generation stealth fighter, the Chengdu J-20, has entered operational service with the People’s Liberation Army Air Force (PLAAF) in limited numbers. While the new fighter is technically operational, the J-20 must still overcome technical hurdles before it enters service in large numbers.
According to CCTV—China’s state television network—the J-20 participated in exercises with other People’s Liberation Army (PLA) assets including ground, air, naval and rocketry forces. However, the J-20 is only in service in very limited numbers because China is unable to mass-produce the aircraft’s indigenous WS-15 engines. Indeed, most western analysts had believed the J-20 was powered by Russian-made Salyut AL-31FN motors, but sources told the South China Morning Post (SCMP) that was not the case for production aircraft. 
“There are still a series of technical problems that need to be tackled [on the J-20], including the reliability of its WS-15 engines, [and the plane’s] control system, stealth coat and hull materials and infrared sensor,” a Chinese source close to the PLA told SCMP.
China made the decision to operationally deploy the J-20 despite its technical problems because of the threat posed the by Lockheed Martin F-35, according to the SCMP’s source. Indeed, more of the stealth fighters are scheduled to join the PLAAF later this year. “It’s urgent for China to show off its achievements as soon as possible,” the source said.
However, while Beijing is trying to rush the J-20 into service to counter the F-35, the Chinese machine is not likely to be a directly analogue to the American jet or its stablemate, the Lockheed Martin F-22 Raptor. The J-20—which appears to be larger than Raptor—is more likely designed to attack the support elements that hold American air operations together such as tankers, AWACS and JSTARs radar planes . Over the vast reaches of the Pacific, where fuel is at a premium, destroying a tanker could achieve the same result as shooting down an enemy fighter.
China is developing the ramjet-powered PL-15 that could have a range as great as 120 miles.  The PL-15 weapon has caused consternation within the top-ranks of the U.S. Air Force with Air Combat Command commander Gen. Herbert “Hawk” Carlisle  citing the Chinese weapon as one of the pressing reasons for the United States to develop a next-generation replacement for the decades-old AIM-120 AMRAAM.
“How do we counter that and what are we going to do to continue to meet that threat?” Carlisle asked during a speech at the Center for Strategic and International Studies  in 2015. Later, during an interview with Flightglobal , Carlisle said that countering the new Chinese missile was an “exceedingly high priority” for the U.S. Air Force. “The PL-15 and the range of that missile, we’ve got to be able to out-stick that missile,” Carlisle said.
Indeed, the problem is not just that the PL-15 would out-range the AMRAAM, when coupled with the J-20, the Chinese could attack the tankers and ISR aircraft that would be the key enablers during any air campaign over the Pacific. A 2008 RAND briefing suggested  that in order to sustain F-22 operations over Taiwan from Guam, the U.S. Air Force would need to launch three to four tanker sorties per hour to deliver 2.6 million gallons of fuel. That’s a fact that has not likely escaped Beijing’s notice.
While there is not much concrete data available about the J-20, the aircraft appears to have been optimized to high-speeds, long-range, stealth and a heavy internal payload. With a combination of reduced radar cross-section and high supersonic speed—armed with internally carried PL-15 missiles—it is possible that the J-20 could be used to threaten U.S. Air Force tankers and ISR assets in the Pacific theatre. As pointed out in the 2008 RAND study—Chinese derivatives of the Su-27 Flanker all but annihilated U.S. tanker, ISR, maritime patrol and command and control aircraft during a simulation using long-range air-to-air missiles.
The U.S. Air Force has looked at dispersed basing and developing robust logical trains  to supply those austere airstrips to counter China's A2/AD capabilities in the Pacific theatre. However, the Air Force does not appear to have fully developed a plan to protect its tanker, ISR and command and control assets from enemy air attacks. The only answer the service has to the problem is that those aircraft will have to be pulled back to safety outside the effective range of the Chinese threat. However, that would also shorten the effective range of the Pentagon’s short-range tactical fighters—reducing their ability to strike deep inside Chinese territory.
Air Combat Command acknowledges the problem and is designing its forthcoming Penetrating Counter Air sixth-generation replacement for the F-22 to operate at extreme long ranges. “That is a strategy others have advertised and we’re familiar with,” Col. Tom Coglitore, chief of Air Combat Command’s Air Superiority Core Function, told me last year.  “We’re analyzing what potential adversaries have indicated they would do and then we obviously have to come up with our own capability to make sure we can still conduct the mission and create the effects desired. So, we’re aware is the short answer and we will be prepared to counter it.”
Dave Majumdar is the defense editor for the National Interest. You can follow him on Twitter: @davemajumdar .