On September 19, 1996, about 0956 Mountain daylight time, a Piper PA-18, N8789C operated as a 14 CFR Part 91 business flight, was substantially damaged when it hit power lines and then terrain while maneuvering about 11 miles south of Gillette, Wyoming. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local flight. The pilot was fatally injured and the passenger received serious injuries. The flight had departed Gillette about 0730 that morning. The flight was part of a predator reduction program. The pilot was in the front seat and a hunter was in the rear seat of the airplane. FAA inspectors documented the scene of the accident. The wreckage was about 60 feet south of a broken power line that was about 40 feet high. The power line ran east and west. The local power company reported that there was a power interruption about 0956. The passenger told FAA inspectors that the pilot was trying to keep up with a fox they had earlier spotted. The passenger reached down to pick up the shotgun, and when he looked up again, the airplane was into the power lines. The passenger got out of the airplane and walked to a ranch house for help. An autopsy was performed on the pilot by Campbell County Coroner. Cause of death was listed as a cervical spine fracture. Toxicological tests performed by the FAA had negative results for carbon monoxide, drugs and alcohol. No pilot or aircraft records were located. Pilot times in this report are based on FAA medical records.