I've read accounts and heard interviews of WW2 bomb crews, who indicated sometimes bombers (under fire) would just explode and disintegrate completely.
I can imagine a critical hit with flack, maybe combined with an air/gas ratio that would cause this affect.
I wonder though, if sometimes a flack round would hit the playload of bombs, and that would set off a chain reaction so to speak. In other words, the bombs would explode and this created the affect witnessed.
