The licence agreement assumed China would keep buying Russian kits, engines and avionics. Instead, Shenyang used what it learned on the J-11 production line to build a Chinese version. The J-11B replaced the Russian radar with a Chinese Type 1493 set and carried Chinese missiles such as the PL-12. Composite parts reduced weight by more than 700 kg, and Chinese reports claim a much smaller radar signature than the Su-27SK.

The hardest part was the engine. The WS-10 Taihang suffered performance and vibration problems in 2008 and 2009, and early J-11Bs flew with Russian AL-31Fs. By around 2011 Chinese sources said about nine-tenths of the aircraft was domestically made. Russia was widely reported to regard the J-11B as a breach of the licence, and the dispute is often seen as a reason Russia became more cautious about selling advanced fighters to China for a decade. By 2011, GlobalSecurity estimated, China was flying some 300 Flanker-family aircraft of all types.

When large formations of PLA aircraft fly into Taiwan’s south-western air defence identification zone, the J-16 is usually among them. FlightGlobal described it in 2021 as China’s top choice for testing Taiwan’s air defences. Its long range, two-person crew and heavy weapon load suit long patrols over the Taiwan Strait and the South China Sea.

The family has also been at the centre of dangerous encounters with Western patrol aircraft. In August 2014 a J-11B intercepted a US Navy P-8 Poseidon about 135 miles east of Hainan, passing as close as about 20 ft in what the Pentagon called an unsafe and unprofessional intercept. In May 2022 a J-16 intercepted a Royal Australian Air Force P-8 over the South China Sea, releasing flares and then chaff in its flight path, and in May 2023 a J-16 made an aggressive fly-by of a US RC-135.

The J-11 programme tracks China’s path to aerospace independence. The first aircraft used Russian AL-31F engines, N001 radars and R-27 and R-73 missiles. The J-11B swapped in Chinese radar and PL-series missiles; the WS-10 engine became standard after its early problems were solved; and the J-11BG and J-16 moved to AESA radars and the PL-15, a missile RUSI says outranges the US AIM-120C/D. In 2021 satellite imagery even showed a Flanker variant parked among unmanned aircraft at the Malan test base in Xinjiang, prompting speculation about optionally crewed or drone-surrogate Flankers.

• J-11: Su-27SK assembled by Shenyang from Russian kits, first two completed December 1998.
• J-11A: upgraded J-11 with Chinese avionics and missile approach warning.
• J-11B: indigenised single-seater with Type 1493 radar, composites and WS-10 engines; first flight about 2003.
• J-11BS: two-seat trainer and combat version.
• J-11BH / J-11BSH: naval air arm versions for land-based coastal defence.
• J-11BG: upgraded J-11B with lighter radome and reported AESA radar.
• J-11D: improved prototypes of 2015 to 2016, not put into production.
• J-16: two-seat multirole strike fighter with AESA radar, in service from about 2015.
• J-16D: electronic attack version.

China does not publish unit or operating costs for its combat aircraft. What can be said is that the J-11 family belongs to the heaviest class of fighters, with two large afterburning engines, a big fuel load and complex radar and electronic systems. Western estimates for comparable aircraft put flight-hour costs far above those of light single-engined fighters; the figure above is a hedged order-of-magnitude range, not an official number.