People's Daily health client reporter Zhao Weide
On March 31, Zhu Tao, director of the Aviation Safety Office of the Civil Aviation Administration, said at a press conference that through nearly ten days of efforts, the investigation has made initial progress. In addition to the two black boxes, important parts such as the engine, the horizontal stabilizer, and the wreckage of the right wingtip were also found, and more than 40,000 pieces of debris that have been collected are being killed, cleaned, identified, sorted and numbered one by one.
Wang Yanan, editor-in-chief of Aviation Knowledge and an aviation expert at Beijing University of Aeronautics and Astronautics, told the People's Daily Health Client reporter, "After finding the black box, data extraction and debris restoration will be carried out, and the wreckage of the crashed passenger plane will go deep 20 meters underground near the main impact point, and the wreckage damage is very serious, which will bring great difficulties to the restoration work." ”
In the core area of the crash site of Flight MU5735 of China Eastern Airlines in Fujian County, Wuzhou County, Guangxi, civil aviation experts tested and confirmed the black box on the spot. Photo by Zheng Bingzhen, Xinhua News Agency
Flight data loggers or accident investigations are more critical
"The two black boxes are very important for accident investigation, and the purpose of setting up two recorders is to provide richer and more diversified information, and to establish data that corroborates and supports each other." Wang Yanan told the People's Daily health client reporter.
Mao Yanfeng, director of the Accident Investigation Center of the Civil Aviation Administration, introduced at the press conference that the voice recorder records various sounds in the cockpit, the flight data recorder records the altitude, speed, pitch angle, rolling angle, heading, vertical speed and other status parameters of the aircraft during the flight, the pilot controls the aircraft's steering rod, steering disk, foot pedal position and call button and other parameters, as well as autopilot, automatic throttle and other airborne system status parameters. Be able to provide true and objective evidence for the analysis of the cause of the accident.
Wang Yanan introduced to reporters that the cockpit voice recorder is equivalent to the collector of sound signals, and all the sounds in the cockpit will be recorded, such as the pilot's discussion of the technical state of the aircraft, the expression of the pilot's operating intention, the warning sound issued by the instrumentation, as well as the communication call between the pilot and the tower, and other background sounds in the cockpit, which is an important evidence for analyzing the cause of the accident.
"Flight data loggers may be more critical to accident investigations." Wang Yanan said that the flight data recorder is based on time changes to record the operating state of the aircraft in real time, including flight altitude, heading, flight attitude changes, throttle position, etc., the collected data is very rich, more intuitive for the investigation, you can judge whether the health status of the aircraft is normal.
Data extraction and wreckage recovery may become the next difficult point of investigation
Wang Yanan told reporters that the black box is often the most core evidence of aviation safety accident investigation, in the case of a complete storage unit, the data can be extracted quickly, and a preliminary conclusion can be reached in half a month to a month or so. However, at present, the two black boxes are damaged, which may bring greater difficulties to technical repair, and it is not easy to say whether it can achieve 100% reduction.
On March 27, the second black box was found in Xinhua News Agency reporter Lu Bo'an photographed
According to the "3·21" China Eastern Airlines MU5735 aircraft flight accident National Emergency Response Command, the first black box cockpit voice recorder found on March 23 is seriously damaged, and the possibility of damage to the storage unit cannot be ruled out, and the professional laboratory of the Civil Aviation Administration has been doing data repair and download work. Li Yong, deputy director of the Aviation Safety Office of the Civil Aviation Administration of China, also introduced that at present, the two black boxes are seriously damaged.
"The second difficulty is the collection and analysis of the wreckage at the site. Damaged parts of the aircraft need to be re-directed to the aircraft's original location and the damage marks of the wreckage need to be performed to determine whether the impact caused the damage or a previous failure caused the damage. The wreckage of the crashed passenger plane was very badly damaged, and the restoration of tens of thousands of pieces of wreckage fragments greatly increased the difficulty of wreckage analysis. This is equivalent to completing the same puzzle pattern, using 10,000 super small puzzles and using 100 pieces of puzzle time and energy is completely different. Wang Yanan said.
Preliminary estimates are that the restoration of debris fragments was at least two weeks or more
Wang Yanan told reporters, "The wreckage investigation is a hard work, but it is very necessary, according to the current situation, the restoration of the wreckage is at least more than two weeks." ”
Search and rescue personnel searched with all their might. Image from Xinhua News Agency
Wang Yanan pointed out that the wreckage investigation may not directly present the cause of the accident, but it can rule out the direction of the accident investigation. For example, no traces of artificial explosives were found in the previous on-site investigation, which excluded an investigation direction, which is the important significance of the wreckage investigation.
"The follow-up investigation focuses on black box data and on-site investigation, including the collection and restoration of wreckage, etc. At present, after the impact, they are all extremely small fragments, and the original information that can be retained may be relatively small." Wang Yanan said.