China did make modification on the AL 31 engine to extend the MTBR from 900 hr to 1500 hr. Here is the article by Reuben Johnson and Photo of the facility from pakistan defense forum
ASIA PACIFIC
Date Posted: 08-Sep-2010
Jane's Defence Weekly
China makes modifications to Russian Salyut AL-31F jet engine
Reuben F Johnson JDW Correspondent - Kiev
Key Points
The PLAAF has developed its own upgrade for the Russian-made Salyut AL-31F jet engine
The development demonstrates that the Chinese have achieved near autonomy in supporting their fighters' Russian-made engines
The Chinese People's Liberation Army Air Force (PLAAF) has developed its own service life extension modifications for the Russian-made Salyut AL-31F engine, a Moscow-based defence and foreign policy think-tank has reported.
The modifications to the AL-31F/FN P.2 series engine increase its operational limits by more than 65 per cent - from 900 to 1,500 flight hours, according to the privately owned Centre for the Analysis of Strategies and Technologies (CAST).
The AL-31F engine is the powerplant for several types of aircraft in the PLAAF inventory: the Sukhoi Su-27 (which is also licence-produced at the Shenyang Aircraft Works as the J-11), the Su-30MKK and the Chengdu Aerospace Corporation J-10. The AL-31FN is a special derivative of the original AL-31F design that was developed by the Salyut plant in Moscow for a single-engine application to be fitted to the J-10.
The service life modifications were reportedly developed at the PLAAF Overhaul Plant Number 5719. The key to the service life extension is a specific set of improved, Chinese-made components that are part of what is described as a "re-manufacturing kit" that is introduced during the process of a full-scale remanufacturing and overhaul process.
The plant is located near the city of Chengdu in Sichuan province, employs 2,000 personnel and is reported to be a model of innovation within the PLAAF's network of repair plants. During the past several years the facility has initiated 63 different research and development programmes and has been awarded more than 20 state prizes for achievements in technological innovation. In the same time period, the plant's assets have more than doubled from CNY1.1 billion (USD147.2 million) in 2004 to CNY2.9 billion today.
The plant's officials credit the success of their overhaul process to a decision taken in 2004, when some of the first AL-31F engines were presented to the plant by the PLAAF for overhaul. A decision was taken, according to the Chinese news sources originally cited, to completely reorganise the overhaul process. This streamlining of the overhaul disassembly and servicing line resulted in a 27.3 per cent decrease in the time required to complete an overhaul and increased the plant's production capacity by 60 per cent.
This level of improvement in the engine's design demonstrates that the Chinese have achieved near autonomy in the support of these Russian-made engines. Russian specialists who spoke to Jane's state that this is "another example of how the technology sold to the Chinese during the 1990s has now been fully assimilated by them. It is only a matter of time before the engines that China produces will be as good as or better than anything designed here in Russia".
