After finding the black box, how many more steps are needed to analyze the cause of the accident?

The search for the cause of the crash of China Eastern Airlines flight MU5735 may be answered more quickly with the appearance of the black box.

As of now, the first black box (cockpit voice recorder) has been delivered to the decoding laboratory in Beijing by a special person on the evening of March 23. Data download and analysis are in progress. The possibility of damage to the storage unit cannot be ruled out at present.

The second black box (flight data recorder) has not yet been found.

Image source: Xinhua News Agency official Weibo

Due to local rainfall, muddy water may bury key items at the crash site, increasing the difficulty of search and rescue. Regarding the black boxes that have been found, experts said that the black boxes must be extracted, decoded, analyzed, and then a situation report is formed. It takes about 10 to 15 days to obtain preliminary analysis results. However, it may take longer to form a final conclusion that can be presented in the accident investigation report.

On March 23, soldiers of the Guangxi Armed Police Corps found one of the two black boxes in the core area of ​​the crash site of China Eastern Airlines flight MU5735 in Teng County, Wuzhou, Guangxi.

Xinhua News Agency (Photo by Xu Dong)

What evidence can the black box provide for us to trace the cause of the accident?

The functions of the "black box" are roughly three aspects: flight accident investigation, pilot monitoring, and aircraft fault diagnosis and maintenance. The most important use is flight accident investigation.

When it comes to flight accidents, how can we reconstruct the crash scene using the massive amount of information recorded in the black box?

Sun Jianhong, dean of the School of Civil Aviation at Nanjing University of Aeronautics and Astronautics, said that the cockpit voice recorder will record the conversations between pilots and the tower, thereby restoring the driving and flight scenes. The flight data recorder can reflect the real-time dynamics of the aircraft, such as changes in flight altitude, route, speed, acceleration, power and other parameter data; whether the aircraft attitude was diving, pulling up or rolling when the air crash occurred; whether the aircraft responded after the pilot issued an action command, and whether the corresponding components executed the command; if the feedback data of the command does not match the command, what kind of fault may have occurred.

Why can’t black box data be synchronized to the cloud?

"Mobile phone data can be synchronized to the cloud, so why can't the important data in the black box be synchronized to the cloud?" Recently, netizens' expectations and attention to the black box have continued to rise.

Due to the large number of flights and the large amount of communication and sensor data, it is technically difficult to transmit all data at all times in real time.

Due to the influence of communication bandwidth, signal blind spots, and meteorological environment, real-time data transmission cannot completely replace the role of traditional black boxes. With the continuous improvement of new-generation communication and navigation technologies such as 5G, 6G, and Beidou, we expect to see real-time data transmission become the future direction of technological development.

On March 24, search and rescue personnel continued their search at the core site of the accident. Photo by Xinhua News Agency reporter Lu Bo'an

How complex is it to protect the black box and why does the analysis take so long?

Falling, crashing, burning, heavy rain... After the plane crash, the black box has been through a series of harsh environments. How can we ensure that it can withstand thousands of blows and still be strong in the design process?

Sun Jianhong introduced that black boxes generally have multiple layers of "golden bell cover". "The main part of the black box shell is generally made of stainless steel, titanium steel alloy and other materials, which makes it waterproof, anti-collision, and fireproof, and can be preserved in some harsh environments. Inside it will have an insulating layer and other high-temperature resistant materials, and the next deeper layer is a protective layer of aluminum alloy or other metal alloys. The innermost is wrapped in the black box's most core component - the storage unit."

Flight accidents often have multiple causes. After finding the black box, experts will extract, download, decode and deduce the evolution of the flight accident through data decoding. When it is difficult to determine the cause of the accident, simulation analysis experiments may even be needed to confirm the cause of the failure.

If the black box is severely damaged, it will take a long time to find it and analyze the data. At the same time, air crash investigations involve multiple parties working together and conducting comprehensive analysis to ensure rigor and fairness, so the investigation time is generally longer. Sun Jianhong gave an example, saying that it took nearly three years from the crash of Air France flight AF447 to the end of the investigation.

10 keywords to look at

MU5735 search progress

recently

Some online

Photos of the crew members of the crashed China Eastern Airlines flight MU5735

Verified by China Internet Joint Rumor Refutation Platform

Identified as false!

Serious reminder

The crash of China Eastern Airlines MU5735 has aroused great concern among the people. The on-site rescue, post-accident disposal and investigation into the cause of the accident are underway intensively.

We solemnly remind all netizens to participate in discussions and express their opinions objectively and rationally, not to post content that lacks empathy, not to believe and spread false information, and to support rescue work with practical actions.

Comprehensive sources: Xinhua News Agency, CCTV News, People's Daily, Science and Technology Daily, etc.