There are long columns of numbers that are currently puzzling. They describe the speed and altitude at which the China Eastern Airlines Boeing 737-800 was traveling in the final minutes of its flight before the plane crashed into a mountainous forested area near the city of Wozhou on Monday. All 132 people on board Kunming-Guangzhou flight MU5375 are believed to have died, but authorities have not yet released an official death toll.
Particularly tragic: According to media reports, the relatives waiting at Guangzhou Airport were not informed about the crash, they found out about the accident like most Chinese via social media. The crash was then the dominant topic on the main news programs of state television. President Xi Jinping said he was “shocked” and ordered full-scale rescue operations and an investigation into the accident.
It is the first major plane crash in China in more than a decade. And one that has so far puzzled security experts. There was wild speculation on the cause of the accident on China’s Internet on Monday. What is known is that the almost seven-year-old 737-800 was flying in good weather at a cruising altitude of 29,000 feet (almost nine kilometers) when, from one moment to the next, it descended almost vertically at a rate of almost 31,000 feet per minute ground shot. For comparison – that’s more than ten times that of a normal descent and about a hundred times that of just before landing. The work of the Accident Inquiry Commission will focus on understanding what exactly happened at that moment. It must have been something extremely unusual: accidents are extremely rare anyway and it is almost never the case that a machine suddenly falls out of the sky in the middle of cruising.
China Eastern has temporarily grounded its more than 100 remaining 737-800s, canceling hundreds of flights as a result. However, other Chinese airlines continue to use the pattern. The 737-800 is the predecessor of the 737 MAX, which is still not deployed in China after two crashes in Indonesia and Ethiopia. The flight control software responsible for the MAX crashes is not yet installed on board the -800.
The victims of the plane crash are commemorated in a field near the site of the accident with a Buddhist ceremony in which candles are lit.
(Photo: Carlos Carcia Rawlins/Reuters)
The day after the crash, the official process got underway. The Civil Aviation Administration of China (CAAC), as the authority of the country where the accident occurred, is conducting the investigation. As is customary internationally in such cases, the American National Transportation Safety Board (NTSB) sent an official representative, since Boeing is an American manufacturer. The aircraft manufacturer is also represented on the commission. According to the guidelines of the International Civil Aviation Organization (ICAO), China must publish an initial accident report within 30 days, in which the status of the investigation that has been worked out up to that point is reflected. Since investigations often take years, the first reports are not always particularly meaningful.
So far, almost no indications have emerged that clearly point to a specific cause. The columns of numbers are not only amazing because of the dramatically high sink rate. In such a dive, the plane should have hit the ground in less than 60 seconds, but it ended up taking about 100 seconds. The data published by the Flightradar24 tracking service shows that the machine briefly (and also very steeply) gained altitude about 40 seconds before the impact, only to then fall again quickly after a few seconds.
In addition to the data, the search for clues on the ground plays an enormously important role. The two flight recorders, the so-called black boxes, which are now being sought, are intended to help clarify the matter. One of the two records all the relevant technical data of the flight, the other the conversations in the cockpit. Every detail can be important. Among other things, the size of the rubble and its location can provide information. What the experts on the ground cannot find can also be decisive for the analysis. If, for example, the tail unit could not be found, this could be an indication that it had already broken off in the air and that the machine would finally no longer have been controllable.