A maintenance man assigned to a naval aviation unit under the PLA Northern Theater Command checks the undercarriage of an aircraft prior to a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

An airborne early warning (AEW) aircraft attached to a naval aviation unit under the PLA Northern Theater Command taxies out of the hangar prior to a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

An airborne early warning (AEW) aircraft attached to a naval aviation unit under the PLA Northern Theater Command taxies out of the hangar prior to a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

An aircraft for special electronic warfare (EW) missions attached to a naval aviation unit under the PLA Northern Theater Command taxies to the refueling pits, preparing for a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

An aircraft for special electronic warfare (EW) missions attached to a naval aviation unit under the PLA Northern Theater Command taxies on the flightline before takeoff during a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

Multi-type aircraft attached to a naval aviation unit under the PLA Northern Theater Command are well-prepared for a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)

A maintenance man assigned to a naval aviation unit under the PLA Northern Theater Command checks the power lines, pipelines and other devices inside an aircraft, preparing for a round-the-clock flight training exercise in east China's Shandong Province in early August, 2021. (eng.chinamil.com.cn/Photo by Xing Yun and Duan Yanbing)