There really wasn't much of a post crash investigation to be honest, health and safety rules didn't seem to apply to the film industry back then!!
I know who the pilot was, but will keep it to myself (wasn't me) but I wouldn't have said it was their fault anyway.
The take off shot was done using channels set into the model runway and plastic pins in the noseleg of the models to ensure they all ran staight down the runway and in line, this meant that the one on the left hand side, once it left the ground was very close to the scaffold, we pointed this out but they didn't seemed to be concerned. Of course eventually there was a collision after many repeated take offs, at which time they moved the scaffolding further away!