What happened
Prior to his planned full-stop landing, the pilot performed a low pass over the 2,000-foot runway to check wind conditions. After observing that the wind socks were limp, indicating no wind, the pilot initiated an approach to runway 18. During the final approach, the pilot noted the aircraft was flying higher than intended and utilized a slip maneuver to descend.
As the aircraft crossed the runway threshold, the ground speed was higher than normal. To prevent the aircraft from overrunning the far end of the runway, the pilot applied excessive braking. While the aircraft was passing over a dip in the runway surface during this braking attempt, it nosed over onto its back. The pilot noted that a slight tailwind appeared to develop during the final approach.
Findings
The approach to runway 18, which is the recommended landing direction, involves flying up the narrow Selway River Canyon and is characterized as a blind approach. Additionally, the first 400 feet of runway 18 is noted for being very rough. The Idaho Airport Facility Directory specifies that inexperienced pilots should utilize this field for emergency use only.