It seems as if a brief vertical climb followed by a near vertical descent would most probably be caused by elevator issues. Proceeding on that assumption to considering structural failures in the elevator itself, attachment points, activation assembly and control linkages to the yoke, also seems most probable. Yes, this is speculative, but when the other factor of nonvisible stuctural failure is introduced, in the context of a 50 plus year old plane flying in a salt water environment, the probabilities do seem to suggest that Brown’s speculations are reasonably accurate. Perhaps the most important take away from this event is to possibly consider that this type of operation, in this age and type of aircraft, presents more risk than other types of aircraft operations, and that potential and actual passengers should be informed that flying in this aircraft presents more risk of injury and death than does flying on a scheduled airline…perhaps even presenting the numbers in an easy to understand form, comparing the death and injury rates to other forms of transportation.