Proposed J-11

Based on experience from the Vietnam War, the PLAAF issued a requirement in 1969 for a STOL light fighter to replace the Shenyang J-6 and Nanchang Q-5. The proposal from the Shenyang Aircraft Design Institute and Shenyang Aircraft Factory was designated "J-11"; it resembled a French Dassault Mirage F1 and was powered by a British Rolls-Royce Spey 512 engine. The project was abandoned as no suitable engine could be procured, and the competing Nanchang J-12 was far more advanced.^[2]

Su-27 purchase

China was the Su-27's first export customer.^[3] China turned to the Soviet Union for weapons following the 1989 Tiananmen Square protests and massacre and the resulting Western arms embargo. China selected the Su-27 over the Mikoyan MiG-29. Three orders were made in the 1990s, and the deliveries of 36 Su-27SKs and 42 Su-27UBKs started in 1992 and continued into the 2000s.^[4]

J-11

In 1996, China Rosoboronexport entered a $1.2 billion agreement^[5] permitting SAC to produce 200 Su-27UBKs^[4] under license. Production would start using kits manufactured by Komsomolsk-on-Amur Aircraft Plant (KnAPPO.) Subsystems (avionics, radars and engines) would be imported from Russia and not be produced under license.^[5] Furthermore, the agreement prohibited China from exporting its production.^[4] Production began in 1997.^[5] The first two were completed in December 1998 but were poorly assembled and required Russian assistance to rebuild.^[4] Five were built by 2000, and another 20 by 2003, by which time production was of high quality and incorporated local airframe parts; Russia did not object to local airframe parts, which allowed KnAPPO to reduce the contents of the kits supplied.^[6] Russia resisted China's demands for upgraded avionics, eventually upgrading the obsolescent N001 pulse-Doppler radar with the improved N001V. Production of the J-11A, an "indigenous" variant, began in 2000. By 2006, at least 105 J-11 and J-11As had been produced with improved domestic avionics.^[4]

Co-production reportedly ended in 2004 with the development the J-11B - a variant with domestic subsystems - in violation of the co-production agreement.^[6][7] However, through 2009 China continued to hold licenses to produce Russian aircraft and components, which included previously-confidential provisions concerning intellectual property (IP). The original licence did not officially include carrier-capable aircraft (eg. Sukhoi Su-33) or variants (eg. Shenyang J-15).^[8]

By 2015, J-11s were upgraded with Chinese-made missile approach warning systems (MAWS). Unconfirmed upgrades included improved cockpit displays, and fire control systems for R-77 or PL-10 missiles.^[9]

J-11B

The J-11B is a multirole variant of the J-11 incorporating Chinese subsystems. It was conceived as a way to remove the J-11's dependency on Russia.^[6] SAC unveiled a J-11B mockup in mid-2002. Three prototypes were delivered to the PLAAF for testing in 2006.^[10] The two-seater J-11BS followed two years after the J-11B.^[6] By 2011, reportedly 90% of the J-11B was based on subsystems and parts designed in China, with the engine presumably being a major part of the remainder.^[6][11] Many domestic subsystems are improvements of those found on the Su-27SK.^[11]

Chinese subsystems on the J-11B include Type 1474 radar, 3-axis data system, power supply system, emergency power unit, brake system, hydraulic system, fuel system, environment control system, molecular sieve oxygen generation systems,^[6] digital flight control system, and glass cockpit.^[10] The airframe is slightly lighter due to greater use of composites.^[12]

The J-11B may carry the PL-12^[6] and PL-15 air-to-air missiles^[13]

Engine replacement

By 2004, the J-11 was being tested with the Shenyang WS-10.^[14] Testing may have started as early as 2002; an image from the 2002 China International Aviation & Aerospace Exhibition allegedly depicted a J-11 with one engine replaced with a WS-10.^[15] WS-10 development proved difficult. One regiment converted to WS-10-powered J-11Bs in 2007, but was grounded for an extended period due to poor operational reliability.^[16] The WS-10A reportedly matured enough after 2009 to power the J-11B Block 02 aircraft,^[17] and Jane's reported the J-11B as powered by the WS-10 in 2014.^[18]

P-8 interception

A J-11BH with two PL-8 and two PL-12 missiles as seen from a P-8.

On 19 August 2014 a J-11B intercepted a U.S. Navy P-8 Poseidon anti-submarine warfare aircraft that was over the South China Sea.^[20]

The U.S. Department of Defense released details at a press conference on 22 August 2014 with Admiral John Kirby as spokesperson. According to Kirby, the incident occurred 135 miles (217 km) east of Hainan Island, in international airspace. The Chinese jet "crossed under the aircraft with one pass having only 50–100 feet [15–30 m] separation. The Chinese jet also passed the nose of the P-8 at 90 degrees with its belly toward the P-8 Poseidon, believed to be displaying its weapons load-out. Afterwards, the J-11 flew directly under and alongside the P-8, bringing their wingtips, as I said, to within 20 feet [6 m]. And then conducted a roll over the P-8, passing within 45 feet [14 m]." He said the "unprofessional" and "unsafe" actions of the Chinese pilot was "not keeping with the kind of military-to-military relationship" the U.S. sought to establish with China. An official complaint was sent to China through regular diplomatic channels.^[21][22] The Pentagon commented further that: "Military activities may be conducted within the Exclusive Economic Zone of another nation as an exercise of the freedoms of navigation and overflight."^[20]

In response, the Chinese Ministry of National Defense spokesman Yang Yujun said that the U.S. criticisms were "totally groundless" as the Chinese pilot professionally maintained a safe distance. Furthermore, he blamed the "massive and frequent close-in surveillance" by the U.S. as the root cause, and called for the end of surveillance flights to improve bilateral military ties.^[23]