I read your post way back in the 900s suggesting something similar - IIRC you suggested the HS deflected leading edge upward into the airflow. To me, the evidence suggests a deflection downward (though possibly both occurred).
My point then was that the HS would have to rotate enough to provide a downward( from level flight aspect ) load to tear the upper fuselage apart starting at the circumferential production joint ( highest stress area ) ahead of the PB. before then breaking off. IF at that time ( milliseconds ? ) one HS broke off slightly before the other, a major side load from the resulting roll and side force on the VS could tear off the aft portion behind the VS front spar.
Hopefully recovery of the jack screw and internal HS structural box will help determine the sequence- and possibly the cause.
