The picture shows the search and rescue personnel conducting a dragnet search at the core site of the “3.21” China Eastern Airlines MU5735 aircraft flight accident.Photo by Xinhua News Agency reporter Lu Bo’an
On March 27, the second black box of the flight accident of “3.21” China Eastern Airlines MU5735 aircraft was found and sent to a professional laboratory for decoding. The accident investigation is still ongoing. Do a good job in accident investigation and handling in a strict and practical manner, and find out the cause as soon as possible, not only to fully and accurately restore the truth of the incident, to clarify the responsibilities of all parties, but also to draw lessons, eliminate hidden dangers, and comfort the deceased. How should the investigation of civil aircraft flight accidents be carried out? What are the difficulties in the investigation of this accident, and when will the results come out? Focusing on the hot issues of public concern during the flight accident investigation, the reporter interviewed relevant experts in the field of civil aviation.
“The investigation of civil aircraft flight accidents is generally carried out in accordance with the provisions of the “Convention on International Civil Aviation”. After the accident, all contracting states, including our country, must follow the relevant provisions of this convention and conduct rigorous and detailed investigations into the accident. Including search and rescue, on-site investigation, experimental verification, cause analysis, and safety suggestions.” Sheng Hanlin, an associate professor at Nanjing University of Aeronautics and Astronautics, told reporters.
The reporter learned that in terms of specific performance of the contract, the Civil Aviation Administration of China issued the “Regulations on the Investigation of Civil Aircraft Flight Accidents” in 2000, and revised it into the “Regulations on the Investigation of Civil Aircraft Accidents and Flight Incidents” in 2007. According to relevant regulations, flight accident investigations are generally organized and implemented by the State Council, the Civil Aviation Administration, the regional administration where the incident occurred, and the regulatory bureau where the incident occurred, based on the accident grade, incident category, and localized management principles. Shu Ping, director of the Aviation Safety Research Institute of the China Academy of Civil Aviation Science and Technology, said that in my country, such major accidents are generally investigated by the State Council or relevant departments authorized by the State Council to organize accident investigation teams, which will set up multiple professional teams, such as flight teams. , Airworthiness Team, Airport Team, Public Security Team, etc., conduct relevant investigations according to their respective functions.
After the “3.21” flight accident of China Eastern Airlines MU5735 aircraft, the Civil Aviation Administration of China activated the emergency mechanism on the day of the accident and sent a working group to the scene.
“In the process of accident investigation, the basic principles of independence, objectivity, in-depth and comprehensiveness should be followed.” Sheng Henlin introduced that the investigation should be carried out independently by the department that organizes the incident investigation, to find out the various reasons for the incident, and to analyze these reasons in depth. factors, including aircraft design, manufacturing, operation, maintenance, support, personnel training, and deficiencies in industry regulations, enterprise management systems, and implementation. “In addition, while identifying and researching various causes and factors related to the occurrence of this incident, we should also pay attention to those unrelated to the occurrence of this incident, but exposed in the incident or discovered in the investigation that may affect safety. question.”
Why continue searching after finding the black box
The reporter checked the “Regulations on the Investigation of Civil Aircraft Accidents and Flight Incidents” and found that Article 30 clearly states that the investigation team should conduct on-site investigations to identify the aircraft, flight process, crew and other on-board personnel, air traffic services, flight dispatch , weather, flight recorders, aircraft maintenance records, aircraft load conditions and loads, communications, navigation, radar, aeronautical information and other service support work, as well as the statements of the parties, witnesses, witnesses and other personnel, explosions A total of 15 aspects, such as physical damage and illegal interference, and the causes of casualties, were collected.
After the black box is found, what aspects will the on-site search work focus on? Sheng Henlin said that the wreckage of the key parts of the aircraft still needs to be found. “The black box records the data during the operation. Whether the aircraft has finally executed or not needs to be determined by the final positions of some key parts in the wreckage, such as the final rudder surface of each rudder surface of the aircraft. Location, etc., comparing and combining the data of the two will help to restore the cause of the accident more comprehensively and clearly.”
For doubtful points or information that needs to be confirmed in the on-site investigation, further analysis can be carried out through experimental verification in the follow-up. “For example, testing the hardware, comprehensively analyzing the data in the black box, and restoring flight information and flight scenarios. Sometimes it is necessary to carry out computer simulation by establishing a mathematical model of the aircraft, or carry out experiments with the help of drones and scaled prototypes to restore the entire flight. The circumstances of the accident.” Sheng Hanlin said.
What is the difference between a preliminary report and a final investigation report
Mao Yanfeng, director of the Civil Aviation Administration’s Accident Investigation Center, said that according to the relevant standards of Annex 13 of the “Convention on International Civil Aviation” “Investigation of Aircraft Accidents and Incidents”, the preliminary report should be sent to the relevant countries and the International Civil Aviation Organization within 30 days from the date of the incident. It should be sent in the ICAO working language.
According to Sheng Henlin, the preliminary report is generally submitted by the Civil Aviation Administration, including the time and place of the flight accident, basic information of the aircraft, flight history, voyage information, casualties, aircraft damage, weather information, etc. “Different from the final investigation report, most of the preliminary reports do not need to wait for the decoding information of the black box to come out, nor do they involve the analysis of the cause of the accident. They mainly provide an explanation of the basic situation of the flight accident.” Sheng Hanlin said.
According to the “Civil Aircraft Accident and Incident Investigation Procedures”, the basic contents of the final investigation report include: factual information identified in the investigation, analysis of the cause of the accident and the main basis, accident conclusion, and unresolved issues in the investigation, etc. It is worth noting that making targeted, timely, comprehensive, actionable and systematic safety recommendations is also an integral part of the investigation report.
“The lessons of each accident are extremely painful. Safety recommendations can be used to prevent accidents of the same cause and prevent and warn accidents of other causes. For example, a certain part of a certain aircraft has a failure, and similar failures occur. It may also appear on other models, and it is necessary to urge the upgrade and replacement at the same time.” Sheng Henlin said.
The reporter learned that at any stage of the investigation, the investigation team can submit suggestions to strengthen aviation safety in a timely manner. For example, the Ministry of Transport of Malaysia put forward in the preliminary report of Malaysia Airlines MH370, suggesting that ICAO evaluate the introduction of a real-time Possibility of tracking positioning system. “Not all air crash investigations will make recommendations in the preliminary report. The specifics depend on the situation at the time, but there will be in the final report.” Sheng Hanlin said.
When will a conclusion be drawn once the accident investigation is launched?
In response to this public concern, Gao Yuanyang, director of the Aviation Industry Research Center of Beihang University, said that if sufficient and effective data or information cannot be obtained, the accident investigation may be very difficult and may take a long time.
Sheng Hanlin told reporters that an important factor affecting the speed of the investigation is the degree of damage to the black box. If the data storage function of the black box is intact, the decoding can be completed in about two weeks; if the memory chip is damaged but not serious, it can be sent to a designated civil aviation professional organization or laboratory for repair and decoding analysis; If the damage is severe, the black box may need to be returned to the manufacturer for a lengthy repair process. The investigation of the entire air disaster requires comprehensive analysis of black box data, aircraft wreckage and other aspects, so it will take longer.
“In general, investigation reports are time-limited and should be completed as soon as possible. Accident investigations organized by regional management agencies should submit reports to the Civil Aviation Administration within 6 months of the accident; accident investigations organized by the Civil Aviation Administration should be completed within 6 months of the accident. Submit a report to the State Council within 12 months after the occurrence. If the cause of the accident is really difficult to find out and the report cannot be submitted on time, an explanation of the situation should also be submitted in a timely manner and a report on the current investigation progress.” Sheng Henlin said.
Talking about the “3.21” China Eastern Airlines MU5735 flight accident, Sheng Henlin said that three difficulties may limit the speed of the investigation: “First, some data show that the plane was basically in a diving state when it crashed, resulting in serious damage to the body and deep wreckage. It is difficult to collect them because they are inserted into the ground and scattered over a large area. Secondly, due to factors such as rainfall and landslides during the search period, some of the wreckage may have been no longer in their original positions when they were found, which is not conducive to subsequent analysis. Finally, all the people on the flight Unfortunately, we can only learn about the situation by looking for witnesses to the accident.”
Taking the Sichuan Airlines “5.14” incident investigation report released by the China Civil Aviation Safety Information System in June 2020 as an example, this final report is 131 pages long and includes hundreds of pages of appendices and 14 experimental reports, which are comprehensive and detailed. It disclosed the facts, analysis, conclusions, safety recommendations, and safety measures taken, etc., and was evaluated as an “extremely solid and meticulous investigation” by many experts in the civil aviation field.
“For the investigation of any accident, we must respect facts and science, and ensure that the investigation conclusions can stand the test of history.” Sheng Henlin said.Return to Sohu, see more