Incident Overview
Sheepherders near the accident site reported observing the twin-engine airplane performing low-level maneuvers in the mountainous terrain. They later heard the sound of ground impact. The aircraft was a restricted category airplane equipped with electronic surveying equipment for low-level airborne magnetic mapping intended for mineral exploration.
Wreckage and Site
The wreckage was located on the eastern slope of a box canyon at an elevation of 7,000 feet. Components and ground scars were found along a 220-foot-long path on the canyon wall, which had a downslope of 42 to 65 degrees. The mission profile for the flight was to conduct a series of low-level flights at altitudes ranging from 200 to 500 feet above the ground.
Examination and Findings
An examination of the airplane, its engines, and turbochargers did not reveal any mechanical anomalies. The investigation did not determine a specific cause for the accident. The terrain and the nature of the low-level operation were noted, but no contributing factors were identified in the available information.