On July 22, 1991, a Cessna 177RG (registration N1573H) operated by Marshall J. Grosboll was involved in an aviation accident near Salmon, ID. Investigators recorded the probable cause as: IMPROPER INFLIGHT PLANNING AND DECISION BY THE PILOT, AND HIS FAILURE TO MAINTAIN SUFFICIENT ALTITUDE AND CLEARANCE FROM MOUNTAINOUS/HILLY TERRAIN. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A witness observed an aircraft enter a canyon at low altitude south of Salmon Airport. The aircraft then turned north and collided with a rising slope on the east side of the canyon, involving impact of the right wingtip and nose.
Accident Details
A pilot departed southbound from the Salmon, Idaho airport after a refueling stop. A witness saw the aircraft enter a canyon south of the airport at low altitude. Subsequently, the aircraft turned back toward a northerly direction and collided with the east side of the canyon.
Impact and Terrain
During the initial impact, the right wingtip and nose of the aircraft collided with a slope rising at an angle of 30 to 35 degrees. Evidence indicated the aircraft was still angled toward rising terrain when the accident occurred. The accident took place at an elevation of approximately 5,600 feet, about 11 miles south of the airport.
Aircraft Examination
Leading edge gouges and chordwise scratches were noted on the propeller blades. The throttle, mixture, and propeller controls were found in the full forward position.