What happened
Following takeoff, the pilot elected to conduct low-altitude flight operations over a reservoir. Witnesses observed the aircraft flying at a very low altitude above the water prior to the incident. On previous occasions, the pilot had performed similar low passes in this manner.
During one such pass, not far from the water's edge, the aircraft encountered a sink. The pilot stated that he checked the power settings and found them to be normal, but noted that the plane seemed to lose all lift. Subsequently, the aircraft struck the water, crashed, and began sinking. Five occupants were able to egress from the aircraft; however, the sixth occupant received fatal injuries.
The investigation
Post-accident examination of the pilot's medical credentials revealed that his last medical certificate was dated November 16, 1984. The aircraft's maintenance records showed that its last annual inspection was completed on August 15, 1984.
A weight and balance check was conducted following the accident. This analysis estimated that the aircraft's center of gravity (CG) was positioned .2 inch behind the aft limit at the time of the flight.