Accident Overview
An airplane on a routine pipeline patrol flight impacted a mountainous, bowl-shaped canyon after approximately 35 minutes of maneuvering flight. The aircraft had departed for its patrol mission, and radar data indicated initial maneuvers to the southwest and then to the northwest of the departure airport.
Flight History
The last five radar returns showed the airplane heading south at an altitude of 2,700 feet mean sea level (msl). The final radar return was recorded about 0.6 nautical miles northwest of the accident site. According to the operator, the area flown by the airplane was not typically associated with the pilot's patrol missions, and the accident site itself was not located within the designated patrol area.
Wreckage Examination
The distribution of wreckage at the accident site indicated that the airplane impacted rising terrain on a southwest heading and nosed over, coming to rest inverted. A thorough examination of the airframe and engine revealed no evidence of any pre-impact mechanical discrepancies that would have prevented normal operation of the airplane.
Pilot Information
The operator reported that the pilot had been conducting patrol missions for nine years and had accumulated approximately 9,900 hours of total flight time.