A Z-9 ship-borne anti-submarine helicopter attached to a flotilla under the South China Sea Fleet of the PLA Navy prepares to lift off from the flight deck of the guided-missile frigate Mianyang (Hull 528) under the instruction of a sailor during a maritime training exercise in waters of the South China Sea on Feb. 23, 2018. (eng.chinamil.com.cn/Photo by Cai Shengqiu)