On the afternoon of March 23rd, emergency headquarters held the second press conference to release the latest progress of the accident investigation of China Eastern Airlines "3.21"and the search for the black box of China Eastern Airlines MU5735. It was announced at the press conference that a black box of China Eastern Airlines flight MU5735 was discovered on the afternoon of 23rd. Due to the serious damage to the appearance of the recorder, the investigation team is currently confirming whether it is a flight data recorder or a cockpit voice recorder. Sun Shiying, Chairman and Party Secretary of China Eastern Airlines Yunnan Co., Ltd. said that the crashed plane was introduced from June 22, 2005 to June 22, 2005, and the aircraft maintenance has been strictly carried out in accordance with the maintenance technical plan, and the technical situation is stable and normal. Before take-off, the aircraft meets the maintenance release standards and airworthiness requirements and is released normally. Mao Yanfeng, director of the Civil Aviation Accident Investigation Center, said that when the plane crashed, the weather on the route was seaworthy and there was no dangerous weather. According to the ground-air communication records between the crew and the air traffic control unit, the crew and the air traffic control unit kept normal communication from Kunming to the sudden drop of altitude on the route. Sun Shiying, chairman and party secretary of China Eastern Airlines Yunnan Co., Ltd., said at the press conference on the 23rd that the flight licenses and health certificates of the three pilots on the flight were all within the validity period, and they were in good health and had a complete flight experience, which met the requirements of the bureau. The pilot-in-command was employed as the pilot-in-command of B737 aircraft in June, 20 18, with a total flight experience of 6,709 hours, the first flight experience of the co-pilot was 3 1769 hours, and the second flight experience of the co-pilot was 556 hours. At present, it is known that the performance of the three pilots is also very good, and the family situation is relatively harmonious. Sun Shiying, chairman of China Eastern Airlines Yunnan Co., Ltd. said that China Eastern Airlines is conducting a comprehensive safety hazard investigation. The grounding of the aircraft does not mean that there must be potential safety hazards in the Boeing 737-800, but an emergency response after a sudden major accident. Whether it is a responsible behavior for passengers depends on the conclusion of the investigation team. China Eastern Airlines will carry out related work in an orderly manner in strict accordance with civil aviation safety management regulations. At present, China Eastern Airlines has sufficient aviation capacity, and the grounding of some aircraft will not affect flights.