Shenyang J-11
The Shenyang J-11 (Chinese: 歼-11 应龙; NATO reporting name Flanker-L) is a twin-engine jet fighter of the People's Republic of China whose airframe is derived from the Soviet-designed Sukhoi Su-27. It is manufactured by the Shenyang Aircraft Corporation (SAC). The aircraft is operated by the People's Liberation Army Air Force (PLAAF) and the People's Liberation Army Naval Air Force (PLANAF). Development

Proposed J-11
In the 1970s, the PLAAF initiated a project to develop a replacement for its MiG-19s. The 
Shenyang Aircraft Factory proposal, designated J-11, was a new light fighter powered by the British Rolls-Royce Spey 512 engine, with better maneuverability than the MiG-19 and better climb rate than the MiG-21. The project was abandoned due to difficulties in obtaining the engines. Background: purchase of the Su-27
China is the first foreign operator of the Su-27 and the only country to acquire the fighter before the Fall of the Soviet Union. The deal, known as the '906 Project' in China, marked the leap in Chinese aviation capability in the 1990s. Discussion of the aircraft purchase began in 1988 when the Soviet Union offered China fourth-generation fighters like the MiG-29. However, the Chinese negotiator insisted on purchasing the Su-27, the most sophisticated fighter Soviets had at the time. The sales were approved in December 1990, with three fighters delivered to China before the disintegration of the Soviet Union in 1991. Russia completed the Su-27 order and later allowed China to assemble and manufacture the Su-27 domestically. The domestically built ones were designated as the "J-11". The earliest batch of Su-27s were stationed at Wuhu air base in the early 1990s. In the next two decades, 78 Flankers were delivered under three separate contracts by the Russian KnAAPO and IAPO plants. Delivery of the aircraft began in February 1991 and finished by September 2009. The first contract was for 20 Su-27SK and 4 Su-27UBK aircraft. In February 1991, an Su-27 performed a flight demonstration at Beijing's Nanyuan Airport. Chinese Su-27 pilots described its performance as "outstanding" in all aspects and flight envelopes. The official induction to service with the PLAAF occurred shortly thereafter. China found some of the delivered Su-27UBKs are "second-handed", consequently Russia delivered 2 more Su-27UBKs to China as a compensation. Differences in the payment method delayed the signing of the second, identical contract. For the first batch, 70% of the payment had been made in barter transactions with light industrial goods and food. Russian Federation argued that future transactions should be made in US dollars. In May 1995, Chinese Central Military Commission Vice Chairman Liu Huaqing visited Russia and agreed to the term, on the condition that the production line of Su-27 is imported. The contract was signed the same year. Delivery of the final aircraft from the second batch, which consists of 16 Su-27SKs and 8 Su-27UBKs occurred in July 1996. In preparation for the expanding Su-27 fleet, the PLAAF sought to augment its trainer fleet. On 3 December 1999, a third contract was signed, this time for 28 Su-27UBKs. All 76 of the aircraft featured strengthened airframe and landing gear – the result of the PLAAF demands air-ground capability. As a result, the aircraft is capable of employing most of the conventional Air-to-Ground ordnance produced by Russia. Maximum Take-Off Weight (MTOW) increased to . As is common for Russian export fighters, the active jamming device was downgraded; the Su-27's L005 ECM pod was replaced with the L203/L204 pod. Furthermore, there were slight avionics differences between the batches. The first batch had N001E radar, while the later aircraft had N001P radar, capable of engaging two targets at the same time. Additionally, ground radar and navigational systems were upgraded. The aircraft are not capable of deploying the R-77 (AA-12 "Adder") missile due to a downgraded fire control system, except for the last batch of 28 Su-27UBKs. J-11
In 1996, China signed a contract for 200 Su-27s through Rosoboronexport under a coproduction scheme for total of , separate from the original Su-27 contract. By the agreement, Shenyang Aircraft Corporation (SAC) would assemble aircraft from kits manufactured by Komsomolsk-on-Amur Aircraft Plant (KnAPPO), and fit them with Russian subsystems (avionics, radars and engines) which would not be coproduced. Production began in 1997. The first two were poorly assembled and required Russian assistance to rebuild. 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. By late 2004, KnAPPO delivered 105 kits, and 95 J-11s were delivered to the PLAAF. 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. Coproduction of the Su-27s reportedly ended in 2004 because China was developing the J-11B - a variant with domestic subsystems - in violation of the coproduction agreement. At the time, Russia refused to comment on the manufacturing of J-11B. At MAKS 2009, Rosoboronexport's General Manager Anatoli Isaykin said Russia and Sukhoi would "investigate the J-11B, as a Chinese copy of the Su-27". At the 2009 Farnborough Airshow, Alexander Fomin, Deputy Director of Russia's Federal Service for Military-Technical Co-operation, reported that Russia had not asked China about the "copying" of military equipment and that China had licenses to manufacture the aircraft and its components, including an agreement on the production of intellectual property (IP) rights. He also confirmed the existence of an all-encompassing contract and an ongoing licensed production of the Su-27 variant by the Chinese. This previously undisclosed IP agreement fuelled speculation about secret contracts or clauses in the original contract. The licence does not officially include carrier-capable aircraft (eg. Sukhoi Su-33) or variants (eg. Shenyang J-15). J-11B
The J-11B "Flaming Dragon" 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. SAC unveiled a J-11B mockup in mid-2002. Three prototypes were delivered to the PLAAF for testing in 2006. The two-seater J-11BS followed two years after the J-11B. 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. Many domestic subsystems are improvements of those found on the Su-27SK. 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, digital flight control system, and glass cockpit. The airframe is slightly lighter due to greater use of composites. The J-11B may carry the PL-12 and PL-15 air-to-air missiles

Engine replacement
By 2004, the J-11 was being tested with the Shenyang WS-10. 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. 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. The WS-10A reportedly matured enough after 2009 to power the J-11B Block 02 aircraft, and Jane's reported the J-11B as powered by the WS-10 in 2014. Operational history
In March 2011 a joint Sino-Pakistani exercise, Shaheen 1, was conducted at a Pakistan Air Force (PAF) base involving a contingent of Chinese aircraft and personnel from the PLAAF. Information on which aircraft were used by each side in the exercise was not released, but photos of Pakistani pilots inspecting what appeared to be Chinese Shenyang J-11B fighters were released on the internet. The exercise lasted for around 4 weeks and was the first time the PLAAF had deployed to and conducted "operational" aerial maneuvers in Pakistan with the PAF. P-8 interception 

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. 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  east of Hainan Island, in international airspace. The Chinese jet "crossed under the aircraft with one pass having only 50–100 feet [] 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 []. And then conducted a roll over the P-8, passing within 45 feet []." 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. 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." 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. Variants
J-11: Chinese assembled Su-27SK derivative with Russian-supplied kits in early production run, differs from the original Su-27SK mainly in avionics:
the original N001M radar developed by Tikhomirov Scientific Research Institute of Instrument Design (NIIP) with NII (Russian acronym for Scientific Research Institute) Argon Ts101 processor installed on Su-27SK is replaced by NIIR N001V radar using NII Argon Ts101M processor. In comparison to the N001M that would lose all remaining targets tracked when engaging 1 of tracked target, the N001V radar on J-11 can simultaneously track 10 targets and engage 1 of the 10 tracked without losing the rest 9 tracked during engagement. The original Russian navigation system was woefully inadequate to meet the PLAAF need, so a domestic Chinese system was installed, but due to incompatibility, information could not be displayed on the CRT display of the Russian flight instruments; and as a result, Chinese added another CRT display atop of the original CRT display to show the navigational information pilot needed. J-11A: Chinese assembled Su-27SK from Russian-supplied kits in late production run, differs from J-11 mainly in avionics:
The original NIIP N001V radar with NII Argon Ts101M processor on J-11 is replaced by NIIR N001VE radar on J-11A using Baguet BCVM-486-6 processor, resulting in N001VE on J-11A being capable of simultaneously engaging two of ten targets tracked with semi-active radar homing (SRAH) air-to-air missiles (AAM) and compatibility for R-77/RVV-AE; as well as capabilities of moving target indication (MTI) and mapping, detecting low flying or hovering helicopters, and increased tracking distance up to 70 km. By the later stage of the production run, China solved the incompatibility problem previously had, and flight instruments was upgraded accordingly, so the two display-only CRT displays on J-11 were replaced by a single multi-function LCD surrounded by control keys on three sides. The original Russian radar warning receivers have also been replaced by a more capable domestic Chinese missile approach warning system (MAWS). A total of 104 J-11’s and J-11A’s have built when production ended in 2007. J-11B (Flanker-L): Chinese-developed variant with domestic subsystems. N001V radar on J-11A has been replaced by a more capable domestic Chinese Type 1474 pulse-Doppler radar with a mechanically scanned slotted-array. Type 1474 is capable of simultaneously tracking 20 targets and engage 4 of the 20 tracked. The original Russian electro-optical targeting system is replaced by a more capable domestic Chinese EOTS that is compatible with Chinese weaponry. J-11B is equipped with fully digitized quadruple fly-by-wire (FBW) flight control system (FCS) that replaced hydraulic FCS, and many analog dials of flight instruments on earlier J-11 & J-11A have been replaced by three multifunction LCDs, with a smaller MFD sandwiched by two large MFD on its flanks. Improved avionics enabled J-11B to be compatible with guided air-to-ground weaponry, and the adoption of more compact and lighter domestic Chinese avionics and advanced composite material not only reduced the empty weight of J-11B by more than 700 kilograms, but also significantly reduced the radar cross section (RCS) to 4 square meters from the original 15 square meters. In addition, electronic warfare (EW) equipment of J-11B is internally mounted, thus eliminates the need to carry EW pods that was required by J-11A and earlier models. Block 02 powered by Shenyang WS-10 turbofan. Production of J-11B ended in 2013. J-11BS(Flanker-L+): A twin-seat version of the J-11B. In 2012, the number of J-11B and J-11BS in service was over 120. J-11BH(Flanker-L): Naval version of the J-11B. It was first sighted in May 2010. J-11BSH(Flanker-L+): Naval version of the J-11BS. J-11BG: Image first shown in September 2019 of an upgraded variant with light-grey radome. Further information confirmed the existence of the J-11BG upgrade including AESA radar, avonics upgrade, helmet-mounted sight, and the capability to launch PL-10 and PL-15 missiles. J-11BGH: Upgrade of J-11BH, the naval version of the J-11BG. J-11D(Flanker-L Variant possibly equipped with fixed electronically scanned array radar, IRST, and capability to fire heavier imaging/infrared (IIR) air-to-air missiles. The airframe makes greater use of composite materials, especially in the engine intakes for lower radar observability. The wings have three hardpoints each. Unconfirmed reports claim it has a new fly-by-wire control system, glass cockpit, improved EW systems, and an improved version of the WS-10A engine. Operators

People's Liberation Army Air Force: 100 J-11A, 180 J-11B and 90 J-11BS ()
 1st Fighter Aviation Division
 6th Fighter Division
 7th Fighter Division
People's Liberation Army Naval Air Force: 40 J-11BH and 32 J-11BSH ()
 Naval Aeronautics University Regiment
 22nd Air Regiment
 24th Air Regiment
 25th Air Regiment

Specifications (J-11A/J-11)

See also

References
Citations

Bibliography

External links

J-11 fighter, Chinese PLAAF
A Flanker by any other name by Bai Wei Air Forces Monthly, May 2012

J-11, Shenyang
Shenyang aircraft
Twinjets
Fourth-generation jet fighter
Aircraft first flown in 1998
Twin-tail aircraft