What happened
A witness observed an airplane departing from runway 33 at Custer State Park Airport (3V0), a dry asphalt runway measuring 4,000 feet by 50 feet. The aircraft became airborne approximately halfway down the runway, after which the pilot pushed the nose down in an apparent attempt to increase airspeed. During the climb, the pilot communicated via microphone that he was experiencing "a little trouble climbing."
After the aircraft passed a ridge at the end of the runway, smoke was observed coming from behind the terrain. Witnesses at a nearby campground later observed the airplane flying westbound through a canyon. One witness noted the aircraft was flying below the canyon's tree and mountain tops, while another observed the plane execute a hard left bank that brought the left wing close to the ground, followed immediately by the crash. There were no survivors.
The investigation
An examination of the wreckage revealed no mechanical anomalies. Environmental conditions at Custer County Municipal Airport, located 11 miles southwest of the site, included a temperature of 60 degrees F and an altimeter setting of 29.95 inches of Mercury. At the accident site, the terrain rises from the airport's 3,980-foot elevation to a 4,400-foot ridge just 1.4 miles north.
A firefighter pilot at the airport noted that winds were out of the west at 20 knots and that runway 33 slopes uphill. This configuration creates challenges for aircraft with insufficient power to climb through rising terrain and canyon walls. FAA toxicology testing performed on the pilot revealed a blood cyanide concentration of 0.85 (ug/ml), which is above the normal level of less than 0.15 (ug/ml).
Calculations using the aircraft's owner's handbook at a density altitude of 7,001 feet indicated a potential rate of climb of approximately 315 feet per minute.