Incident Details
During a flight, the pilot encountered an engine problem and initiated a landing on a road. The engine subsequently began to run better, so the pilot abandoned the landing and continued to the destination. After landing, the pilot discovered that approximately 18 inches of the vertical stabilizer and a corresponding portion of the rudder were missing. The pilot later denied being aware that the aircraft had struck any obstructions.
Investigation
An investigation revealed that an aircraft had been observed flying at treetop level above Interstate Highway 94 for a distance of 15 to 17 miles. The missing pieces of the vertical stabilizer were found adjacent to the highway. Additionally, damage was found on two of three power lines located near the highway at an estimated height of 90 feet above ground level.
Findings
The missing components and the damage to the power lines indicate a probable collision during the low-level flight, though the pilot reported no awareness of any impact. No other contributing factors were identified.