A look at the debris field suggests the aircraft 'may' have been intact.
The Herc in the wing separation video is an A-model, built 1957. This one is an H-model, built 1981, and heavily modified for the task. They are like chalk and cheese.
They don't normally do "dry runs". They normally follow the spotter aircraft in on its run, first time.
I believe the aircraft had just completed a run.

