Trainees practise at the Guanghan Campus of China Aviation Flight University of China in Deyang, southwest China's Sichuan Province, Aug. 19, 2016. Aviation security officer, also known as flight security officer, is responsible for guarding safety of persons on board and plane on a civil aircraft. To become an aviation security officer is not an easy thing. After a preliminary training for two months and a half, applicants must have at least 100-hour training on real planes. Despite of rigid test, many Chinese young people choose this job as their career. (Xinhua/Chu Hongyu)