Accident Overview
On 28 August 1986, a single-engine aircraft collided with rising terrain during a nighttime takeoff approximately 1.5 miles from the end of the runway. The airport elevation was 5,586 feet, and the collision occurred at an elevation of about 5,600 feet. A witness reported seeing the aircraft take off but stated that it did not climb after departure. The accident site was in an area isolated from ground lights.
Pilot Background and Medical Status
The pilot had undergone surgical removal of an acoustic tumor from his right ear on 1 May 1986. The surgery included removal of the 8th nerve (balance nerve). His attending physician recommended a recuperation period of approximately one year due to equilibrium problems associated with the procedure. On 12 July 1986, the pilot received a first-class medical certificate valid for flight test only.
Pilot Experience and Duty Period
According to the pilot’s logbook, his most recent night flight occurred on 22 March 1985. At the time of the accident, the pilot had been on duty for approximately 14 hours.
Aircraft Examination
A post-crash examination found no evidence of mechanical failure or malfunction of the aircraft structure, flight controls, engine, or propellers.
Official Findings and Probable Cause
The official investigation identified the following factors related to the pilot-in-command: failure to follow procedures/directives; inadequate qualification; lack of recent experience in the type of operation; physical impairment; dark night conditions; failure to attain a proper climb rate; spatial disorientation; fatigue; and degraded visual/aural perception. The terrain was mountainous/hilly, and clearance was not maintained.
The probable cause of the accident was the pilot-in-command's failure to follow procedures, inadequate qualification, lack of recent experience, physical impairment, dark night conditions, failure to attain a proper climb rate, spatial disorientation, fatigue, and degraded visual/aural perception, combined with mountainous terrain and failure to maintain clearance.