An investigation determined that the most likely cause of that crash was that the pilot was momentarily impaired because of a prior rib injury. Pain from the rib injury might have kept the pilot from tensing his abdominal muscles during a turn causing him to suffer tunnel vision.
As a military pilot with close to 5000 hrs of high performance flying I have to say "What a load of cr@p" How the hell do investigators come up with this wild rubbish and who the hell signs off on it?