HEAD SKINNER
I would say because only one was built the NTSB could only base their findings on the total separation of the wing at normal cruise as over stress of the aircraft.Not having any other SJ-1'S accident reports to refer to. His Family watching stated that they saw the wing seperate on final. Logs books showed 926 total time and actual 8hrs in head skinner. As Sincotc stated it is easier to say pilot error than in flight total failure. It was easier in 1964 because they did not have testing they have today to know what really happend.