On Thursday, September 27, 2018 at 10:53:23 AM UTC-7, krasw wrote:
What if wing was weaker than intended...

The NTSB preliminary report makes it clear that very high load factors were applied to the wings. One witness reported the wingtips at or near vertical, another reported the wingtips almost touching. Even allowing for some exaggeration, it appears that the wings supported loads well above limit or even ultimate load rating.

I agree that this is a very distressing accident. The facts in evidence suggest some sort of pitch control malfunction. But of course there is no proof one way or the other, and the post-accident fire has likely erased the evidence. Though perhaps the cause will be revealed by interference signatures on metal parts.

--Bob K.