"Coincidence? Not a chance. Replacement with another engine? Unless it's a very close copy, that requires re-work of the entire fighter design and takes years. Just ask the J-10 project team."

China has a parallel program to replace the RD-93 with it's own WS-12 turbofan. This has been specifically designed to be of almost exact dimensions as the RD-93. It is reported that the engine is very close to design cerification and imminent production.

This is similar to the way that WS-10As are being built to power Chinese built SU-27s and the new J-10 fighter. Very little modification is required to put one in place of an AL-31 engine as they are of virtually the same dimensions. That engine was certified at the end of 2005 and is now in serial production. It is more powerful and also reported to be far more reliable than the Russian AL-31 that powers SU-27s and the first batch of J-10s.

Chinese engine technology has come a long way and is currently at the level of what Russia has. Only the Europeans and US are ahead of China now.

A more powerful version of the WS-10A(9:1 T/W ratio in contrast to the 7.5:1 of the current version) is in testing phase, and a new generation engine(10:1 T/W ratio) is in the design stage but that may not see the light of day till around the middle of the next decade.