Accident Sequence
Witnesses reported seeing the accident airplane spinning in a nose-down, near-vertical attitude before it collided with the ground. The accident site was located approximately 3 miles from the approach end of the intended runway. The pilot was conducting an instrument landing system (ILS) approach at the time.
Investigation Findings
A review of radar data revealed that the private pilot had difficulty maintaining altitude and airspeed while on final approach. The data showed significant excursions above and below the glidepath, as well as large variations in airspeed. Interviews with other pilots in the area just prior to and after the accident indicated that icing conditions existed in clouds near the airport. However, first responders to the accident site reported that there was no ice on the airplane. A postaccident inspection of the airplane, its engine, and its flight navigation systems discovered no evidence of preimpact anomalies.
Navigation System Analysis
An analysis of the airplane's navigation system light bulbs suggested that the pilot had selected the GPS mode for the initial approach but had not switched to the proper instrument approach mode to allow the autopilot to lock onto the ILS. No other causal factors were identified in the investigation.