On September 7, 2003, about 1200 Alaska daylight time, a tundra tire-equipped Piper PA-18-180 airplane, N8597D, received substantial damage when it nosed over while landing at an off-airport site in mountainous terrain. The accident site was approximately 30 miles west of Eagle, Alaska. The solo airline transport pilot was not injured. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The flight departed a remote, off-airport site about 1100, and the destination was the accident site. Visual meteorological conditions prevailed, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on September 8, the pilot of the accident airplane related that he was landing on a mountain ridgeline. He indicated that the airplane touched down on the rough and uneven terrain without difficulty, but during the landing roll, he inadvertently applied excessive braking action. The airplane subsequently nosed over, and sustained structural damage to the rudder and wing lift struts. The pilot reported that there were no preaccident mechanical anomalies with the airplane.