According to reports, FC-31 is the fourth generation of dual-engine medium stealth fighter developed by Shenyang Aircraft Industry Group (China adopts the mainstream fighter division standards in Europe and America), codenamed "Eagle", which adopts dual-engine, single seat, fixed double inclined vertical tail, no canard and clam inlet. At present, there are three main uses for speculation: First, it forms a high-low match with the Chinese heavy stealth fighter J -20, although the military has not established a project; The second is the proposed export model of stealth fighters; Third, it will be developed into a new generation of stealth carrier-based fighter to replace the J-15 fighter. At 10: 32 am on October 31, 2012, the J -31 made its first flight successfully. China has become the second country in the world to test two fourth-generation aircraft prototypes simultaneously. The J -31 was tested again on March 3, 2014. According to on-site netizens, the J -31 fighter plane conducted two test flights that day, one in the morning and one in the afternoon. At about 12 noon on March 1st, the latest J -20 fighter jet numbered 2011 made its first flight successfully, and this test flight of J -31 fighter jet followed the first flight of J -20 in 2011. On April 10, 2014, the J -31 flew again in January.