Last year, China was believed to be producing, at the rate of twenty aircraft a year, a licensed version of the Russian Su-30. The Chinese aircraft, called the J-11, is believed to now include better electronics and some other Chinese design modifications. The changes may be great enough to justify considering this a new version of the Su-30, and some are referring to it as the J-11A. An even more "Chinese" (with many more Chinese made parts) Su-27 existing in prototype form as the J-11B. There are believed to be about 16 of the J-11As in service, and the success in developing and building this aircraft may be the reason behind China wanting to halt imports of Russian made Su-30s. China can manufacture most of the components of the J-11, the one major element it must import are the engines. China just bought another hundred engines for the Su-30 and J-11, but is also reported close to achieving the capability of building the engines themselves. China has, for decades, painstakingly built up its jet engine building capability. Manufacturing powerful jet engines involves mastering a wide variety of technologies, and China appears determined to become self-sufficient in this area. China received its first 26 Su-27s (an earlier model of the Su-30) in 1992, and began building the J-11 (using Russian components) in 1998. There were quality control problems at first, and China has spent the last six years perfecting its aircraft construction procedures. China may have as many as 200 Su-27, Su-30 and J-11 aircraft in service by the end of the year.