such a tragic loss..any guesses what caused the pilot to lose control by looking at the video?

Alternate angle:

I'm not gonna make any guesses. RIP Jane.

Yes - very sad loss of a talented performer and her pilot

Something happen as he rolled inverted.....didn't get the wings level inverted....and then pulled positive (looked like a very hard pull)....flight control failure? Sad indeed.

I've never understood "wing walking". People don't get out of race-cars and walk all on top of them to show off, nor do they get out of trains and walk all forwards and backwards doing stunts (except in movies). It just seems dangerous to the point of stupid, as you won't have enough time to pull your chute at those altitudes and the consequences are just way too high IMO. This coming from someone that participates in quite a few "extreme" sports, but I tend to judge risk pretty well.

I was acquainted with them both, as both were very well known and liked in the northern Virginia aerobatic community.

I would guess that Charlie Schwenker had thousands of hours of acro time; he owned an S1S and an Extra 300. A more experienced aerobatic pilot would be hard to find.

Obviously this is a guess, but either the control stick slipped out of the pilot's hand, or the control cables snapped. Definitely it was her weight at the wing tip that pulled that plane into the ground.

When they rolled inverted, that Stearman rolled about her as the CG.