What is Russia's position on China copying its Flanker jets?

Question

We saw that the USA is very vocal about China infringing on the law of intellectual property of the USA.

What is Russia's position on China copying its Flanker jets?

Answer 1

China copying Su-27 was (perhaps) first reported in 2008. The RFE RL reported on April 22, 2008 about the copying story that appeared in the Russian newspaper Nezavisimaya gazeta.

IS CHINA COPYING RUSSIAN ARMS TECHNOLOGY FOR ITS OWN EXPORTS?
The daily "Nezavisimaya gazeta" wrote on April 22 that "China is on its way to becoming a major arms exporter by shamelessly copying Russian military hardware" [...]
"Moscow's hopes to strengthen its position in the Chinese arms market by permitting China to assemble [Sukhoi] Su-27SK [Flanker] fighters under license proved futile. Once it mastered the technology, China produced its own versions by itself...with the aim of selling the fighters to third countries. Russia officially informed China that [the practice]...constitutes a violation of existing agreements, and threatened litigation."

I haven't been able to find anything on threatened litigation as mentioned above. Russia, now aware of copying became cautious. Exports decreased. The sole reason is not Russia not exporting but also China increasing its own production.

Russian concern over China's reverse engineering contributed to a rapid decline in arms sales between the two countries in the mid-2000s. Whereas China accounted for 60% of Russian arms exports in 2005, the figure fell to 8.7% by 2012.

https://asia.nikkei.com/Politics/International-relations/Russia-up-in-arms-over-Chinese-theft-of-military-technology

As a result, from 2008 to 2010 Russia’s arms exports as a percentage of its overall arms business dropped from 18 per cent to 10 per cent, to about US$ 800 million (Trenin 2012: 42; SIPRI Arms Transfers Database 1991–2011). Another reason for the reduction in arms’ sales was that China sought more sophisticated technology than Russia was willing to offer. As for copying, once China had mastered the technology of Russia’s Su-27SK Flanker fighter, it produced its own version, the J-11B, to sell to third countries, and subsequently ended its licence-contract with Moscow. Beijing even exported the J-11B to Pakistan without a permit from the Russian aircraft manufacturer Sukhoi (Petrov 2008). China was eager to do the same with the Su-33 Flanker-D carrier-based fighter, but the Russians were now aware of this copying attempt.

_{De Haas, Marcel. "Russian-Chinese Security Relations." Clingendael Netherlands Institute of International Relations 3 (2013): 19.}

Another step Russia took was insisting to buy in bulk. For instance, in 2010 Russia sold S-300 air defense system to China at an estimated value of $2.25 bn. Must be noted that the Russians had started developing even S-500 by then.

China couldn't acquire Su-33 from Russia. The Fight Global reported

Beijing unsuccessfully tried to buy Su-33s from Russia early this decade. Undeterred, it bought a Su-33 prototype from Ukraine in 2001 and used that to develop its version, designated the Shenyang J-15.

Sukhoi's CEO had commented

"There are licence agreements in place when countries buy our aircraft and it is illegal to produce a copy of it without getting our agreement, We are always looking very carefully at what the competition is doing. What I can stress is that no copy is equal to the original, it will always be inferior to the original product. They do not have the technological capabilities that we have."

ibid.

The same source reported

Russia's refusal to sell Su-33s, sources say, is linked to China blatantly copying its Su-27SK flankers. China signed a $2.5 billion deal in 1995 to licence-produce 200 Su-27SKs, designated the Shenyang J-11A.
Moscow cancelled the agreement in 2006 after Shenyang Aircraft manufactured 95 aircraft, when China developed the J-11B, a clone of the Su-27SK with indigenous systems, in violation of the contract.