Question: The WS-15, code name Emei, is a Chinese after burning turbofan engine, a stealth, twinjet, fifth-generation fighter aircraft developed by China's Chengdu Aerospace Corporation for what airforce?
Sentence (from "Chengdu J-20"): In March 2017, Chinese media claimed that the aircraft has entered initial operational capability phase with limited service within Air Force.
Relevant evidence: No