[only1percent]

People are being too polite to say — but it’s almost certainly murder-suicide by plane, with an outside chance of an autopilot hack (i.e., murder without the suicide.)

There are really no casualty events that can cause the trajectory noted.

There are very few casualty events that could have caused the initial dive ... but the key fact is the 20 second reversal of the dive. This would not have been possible with the kind of casualty could have caused the initial dive.

However, it is very well explained by Pilot A or hacked autopilot putting the plane into a dive, Pilot B recovering control for 20 seconds, and Pilot A or autopilot taking the controls back and resuming the fatal dive, or (less likely) the dive reversal having been so far out of the performance envelope wings or stabilizers detached or control surfaces failed.

[TheConservativeTejano]

People are being too polite to say — but it’s almost certainly murder-suicide by plane, with an outside chance of an autopilot hack (i.e., murder without the suicide.) There are really no casualty events that can cause the trajectory noted. There are very few casualty events that could have caused the initial dive ... but the key fact is the 20 second reversal of the dive. This would not have been possible with the kind of casualty could have caused the initial dive. However, it is very well explained by Pilot A or hacked autopilot putting the plane into a dive, Pilot B recovering control for 20 seconds, and Pilot A or autopilot taking the controls back and resuming the fatal dive, or (less likely) the dive reversal having been so far out of the performance envelope wings or stabilizers detached or control surfaces failed.

Chinese pilots do not know how to fly anything.

Chinese pilots are the craziest pilots in the world.

The pilots of these planes are only trained to get from point "A" to point "B", and they will fly the plane thru turbulence and so forth.