China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)

China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)

China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)

China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)

China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)

China's ship-borne helicopter is seen during the Rim of the Pacific (RIMPAC) multinational naval drill. China's navy exchanges copter landing experiences with other participating countries in the drill. (Photo: Ecns.cn / Mao Jianjun)