What happened
During a personal cross-country flight conducted under instrument flight rules, the aircraft was tracking a west-southwest course at 15,800 feet MSL while approaching its destination. The pilot was cleared for a GPS approach and successfully passed the initial approach fix, beginning a descent according to the established procedure. Radar tracking showed the aircraft remained above the 12,000 feet MSL minimum altitude during the initial segment of the approach.
As the flight approached the intermediate navigation fix, the aircraft began a right turn approximately one mile prior to reaching the fix. During this maneuver, the descent rate increased significantly, averaging 4,000 feet per minute. Following this turn, the aircraft tracked northbound for roughly 1.5 miles, experiencing a period of descent at 3,500 feet per minute followed by a climb at 1,800 feet per minute. The aircraft then initiated a second right turn.
Radar data indicated a rapid loss of altitude during the final stages of the flight, with the descent rate reaching 7,000 feet per minute between the final two recorded altitudes of 10,100 feet and 8,700 feet MSL. At the time of the final radar contact, the pilot notified air traffic control that the aircraft was in a spin and that recovery efforts were underway. No further radio contact occurred. The aircraft eventually struck the surface of a reservoir at an elevation of 6,780 feet, coming to rest under 60 feet of water.
Findings
Post-accident inspections of the engine, propeller, and airframe showed no evidence of mechanical failure or malfunction prior to the impact. Meteorological conditions at the time of the accident included cloud layers with bases near 10,000 feet MSL, meaning the aircraft was operating in instrument meteorological conditions. Data also indicated the presence of light turbulence and the possibility of light icing between 12,000 and 16,000 feet MSL. While the pilot initially managed the descent correctly, the aircraft entered a spin during the approach maneuvers, and the cause for the loss of control and navigational deviation remains undetermined.