The Republic of China Air Force issued a press statement on May 14 saying that a Chinese Y-8 electronic warfare (EW) aircraft was operating on the west side of the Taiwan Strait in the morning.
Although the press statement refuted reports that the aircraft was operating over the M503 airway. Statistics pulled from ADS-B data showed an unidentified aircraft squawking 1717 and Mode-S transponder code of 79A6B8 flying along that aircraft at around 0200 GMT.