Narrative
An airplane collided with mountainous terrain during an en route climb on a course that took it into a box canyon. The pilot had departed from an airport located at 2,390 feet mean sea level (msl) after a day of physical exertion. The temperature at the airport was about 90 degrees Fahrenheit.
Approximately 20 minutes into the flight, as the pilot approached a pass in the mountainous terrain, he realized that what appeared to be level terrain below was actually the steep walls of a narrowing canyon. The pilot noted an increase in air turbulence and downdraft conditions. He attempted to maneuver the airplane out of the canyon but did not have adequate altitude, necessitating a forced landing onto a logging road at an elevation of about 6,000 feet msl.
Prior to touchdown, the left wing impacted a tree, and the airplane subsequently landed hard on the road. The pilot egressed the airplane as it became engulfed in flames. The pilot reported no pre-impact mechanical malfunctions or failures with the airplane.
Analysis
Using the standard lapse rate of 3 degrees Celsius per 1,000 feet of altitude, the density altitude at the accident site was calculated to be about 8,600 feet. The high density altitude likely affected aircraft performance, as warmer and less dense air reduces lift and engine efficiency. However, the source provides no explicit causal link between the density altitude and the accident.