This one:
By the way, I once met a pilot of one of the other planes in that formation. He saw the event first hand (so he said anyway).
Re: I have seen the same footage of a B-24 being hit and the wing immediately crumpling due to "flak". As I recall, the cause was actually from a bomb dropped by another B-24 higher in the same formation. A direct hit on the wing by a 500 lb bomb, even if it didn't explode, would explain the catastrophic failure. Reluctance to admit an incident of friendly fire would explain the incidents attribution to a flak hit."
You are confusing different World War Two film clips.
The B-24 clip shows a B-24 being hit by flak right in the wing root, causing an explosion with the right wings folding up...
There is another almost exact incident but with another high wing design, the Martin B-26 twin engine bomber. The results are the same.
The B-17 footage shows a B-17 stick of bombs falling into the right tail elevator, knocking it off. The stricken 17 keeps flying for a while fading to the right until it goes into a spin and crashes...
I do not have links to these on the web, but I have seen them over and over in different programs for some 50 years.
This one:
By the way, I once met a pilot of one of the other planes in that formation. He saw the event first hand (so he said anyway).