Bird avoidance.
I keep wondering about the lightplane pilot getting away with the "Has to avoid birds, so must dive under bridge"- story.
Same defence must/could apply, if the helicopter pilot is found.
The French and Spanish pilots. Are they only doing this "on tour", or is it everyday happenings at home?
According to the link Tex Johnston did "aileron roll" the Dash 80, and not "barrel LOOP!" it.
No wonder the onlookers needed heart medicine.
