Accident Overview
An airplane operating a 57-mile cross-country flight through a valley struck a hill approximately 34 miles north of its destination airport. The accident occurred under dark, nighttime visual meteorological conditions. The pilot frequently used the airplane for commuting between the departure and destination points and had accumulated thousands of hours of experience flying in the valley.
Terrain and Wreckage
The wreckage came to rest on a hillside with a slope of about 25 degrees, located roughly 275 feet below the top of the ridgeline. A heavily traveled highway ran adjacent to the hill, oriented north-south, consistent with the airplane's route of flight. The wreckage distribution path measured 400 feet along a magnetic bearing of approximately 340 degrees.
Impact Analysis
Examination of ground scars at the impact site indicated that the airplane was in controlled flight and in a near level configuration at the moment of collision with the terrain. At the time of the accident, the moon was 3.7 degrees above the eastern horizon but was obscured by mountains to the east. It is likely that lights from automobiles on the highway would have been visible to the pilot, but there were no lights to distinguish the rising terrain.
Aircraft Examination
A thorough examination of the airframe structure and engine revealed no evidence of any preimpact failures or malfunctions.
Probable Cause
No probable cause was determined from the available information.