On March 5, 1999, approximately 1630 Pacific standard time, a Piper PA-12, N4328X, registered to and being flown by a private pilot, was substantially damaged when the aircraft impacted sharply up-sloping terrain just short of the landing threshold at the pilot's personal, non-airspaced landing strip near Salem, Oregon. The aircraft was on a short final approach, landing to the south, when the main gear impacted the terrain and collapsed. The aircraft then nosed over. The pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and originated from Salem approximately 1610. The pilot reported that "while practicing [a] short field approach, I landed a little shorter than I planned. The landing wheels contacted the very end of the runway, which caused the nose to make contact on the grass strip, and [the plane] flipped over on its back. " The pilot stated that there was no mechanical malfunction with the aircraft at the time. An inspector with the Federal Aviation Administration's Hillsboro Flight Standards District Office examined the aircraft and accident site/landing strip. He reported that the landing strip was approximately 900 feet in length, 45 feet in width, and oriented along a north/south magnetic bearing (refer to DIAGRAM I). The landing surface was grass and the north end of the strip descended sharply approximately 20 feet (vertical height) to lower terrain (refer to photograph 1). Marks in the soil at the crest of the up-sloping edge of the runway's north threshold matched the distance between the main landing gear, and were consistent with a gear impact (refer to photograph 2). The aircraft was observed to be inverted at a point approximately 18 feet beyond the main gear impact at the up-sloping north end, and displayed extensive aftward left main landing gear deformation(refer to photograph 3).