Did the pilot experience spatial disorientation because weather visibility at night led him to rely solely on his flight instruments to maintain flying stability? It was reported early on that Kennedy did not have IFR training as required for a pilot to place his airplane in poor visibility conditions. Darkness overcame the brightness of day. FAA regulation clearly state that, "No pilot may assume control over an airplane while flying in Instrument Meteorological Conditions (IMC) without first obtaining the necessary Instrument Rating."
Was Kennedy's forward horizontal visibility taken away by early on by haze, and then by darknes? Did the dark blackened waters below combine with a blackened sky above to remove any sensation of whether or not the airplane was flying up or down? We know that the crash occurred more than an hour after sunset. The sky above, water below, and distant land ahead may have been collectively obscured. All of the above factors have been known to contribute to airplane accidents over the years as documented in NTSB accident reports.
Investigators will probe many areas searching for what caused the accident. Aviation physiology is included in the extensive investigation looking for physical factors that may have inhibited Kennedy's ability to land the airplane under stressful conditions. Did fatigue and tiredness play a role? Kennedy was flying his Saratoga II HP airplane at a time when his physical capacities were lessened by fatigue. Some degree of tiredness was proably evident at the time of the crash contrasted to his physiology at takeoff time.