Accident Sequence
An instrument-rated pilot was cleared to descend to 4,000 feet for radar vectors to a non-precision instrument approach in instrument meteorological conditions (IMC). Radar data covering the final 1 minute 23 seconds of the flight showed the airplane leveled at 4,000 feet for approximately 35 seconds, then varied between 3,800 and 3,900 feet for the remainder of the recorded data. During this period, airspeed decreased from 131 knots to 57 knots.
Witnesses observed the airplane descending in a spin and reported hearing the engine running. Recorded engine data indicated an increase in engine power near stall speed, likely the pilot's response to the low airspeed. The airplane's damage was consistent with a low-speed impact and rotation about its vertical axis. The pilot did not transmit any abnormality or emergency to air traffic control.
Post-Accident Examination
A post-accident examination of the airplane revealed no anomalies that would have precluded normal operation. The investigation found no mechanical or system failures contributing to the accident.
Pilot Background
During training on the accident airplane, the pilot's instructor recommended 25 to 50 hours of flight in visual meteorological conditions (VMC) before flying in IMC to become more familiar with radios, switches, and navigation equipment. At the time of the accident flight, the pilot had only 14 hours of flight time in the accident airplane. However, the investigation could not determine whether this limited experience played a role in the accident.
Probable Cause
The official probable cause was determined to be the pilot's failure to maintain airspeed in instrument meteorological conditions, which resulted in an aerodynamic stall.