Update: New Developments in Crash of China Eastern Airlines 737

To recap, the China Eastern Airlines Boeing 737 crashed near Wuzhou, China, killing all 132 on board. The plane was a 2015-model 737-800, a newer version of the airliner that has an excellent safety record.

As hopefully everyone is aware by now, it was not, a 737 Max, a later model that has larger engines and a stability control system that was at the center of the controversy surrounding a pair of fatal crashes that claimed 346 lives, caused by a poorly designed, supported and fielded MCAS stability system.

The first development was the discovery a few days ago of the airplane's flight data recorder. The plane's cockpit voice recorder had been located a week before. As we're written, finding the recorders and being able to get data off them will be critical in investigators understanding what happened to the plane.

The crash seems inexplicable. It happened as the plane was in cruise ready to begin its initial descent to its destination airport. At around 29,000 feet, it began to descend at a rapid rate, leveling off somewhat at around 8,000 feet, before continuing its rapid descent into the ground.

The second bit of news is that a part of the plane--we're guessing part of the tail--was found a couple of miles away from the crash site. This seems to confirm what looks like, on the grainy video, captured by a mining company's remote security cam, a part or parts of the aircraft separating in flight, which sometimes happens when a pilot attempts a recovery from a steep, high-speed dive. We don't know. how it happened, but if investigators can succeed in getting data off of the flight data recorder, there's a very good chance they will figure out what happened.

Today, we do not know yet. One thing we do know is that less than 10% of such crashes happen in cruise or during the initial descent. The causes of what caused the plane to go out of control are limited to a few possibilities, some of which are very troubling.

It could have been the failure of the airframe or flight control system, though the 737-800 is a thoroughly proven design, making that less probable though not impossible---previously unknown system failure incidents must happen a first time. It could also have been a maintenance error that led to the initial loss of control. Such things are not unknown. The American Airlines Flight 191 DC-10 crashed on departure from O'Hare after an engine fell off shortly after takeoff due to a maintenance error.

One possibility that China was dismissing before it had done much investigating is that crash could have been due to an intentional act, an act of terrorism, sabotage or pilot suicide. Over the last couple of decades, there have been several crashes due to such causes, so investigators are sure to be considering an intentional act as a possible cause. Chinegovernmentent sources said that there were no indications either pilot was under any kind of distress.

But causes of such crashes can be extremely difficult to track down. The crashes of TWA 800, a Boeing 747, over the Atlantic was finally traced to an explosion of a center fuel tank, and the crash of SwissAir 111 near Halifax, Nova Scotia, Canada, was finally traced to a fire that started mostly likely in the entertainment system and spread rapidly.

It is certain that due in part to the controversy surrounding the 737 Max crashes, the world will be closely watching the investigation into the crash of China Eastern 5735.