On April 14, 1997, about 2245 eastern daylight time, a PA-28-161, N21123, was substantially damaged during a landing overrun at Butler Farm Show Airport (3G9), Butler, Pennsylvania. The certificated commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight conducted under 14 CFR Part 91. In a written statement and during a telephone interview, the pilot stated that he departed runway 18, a 2,580 foot asphalt runway with a displaced threshold of 180 feet. When he returned, he entered the left downwind for runway 18. During the final approach the airplane was too high, and he performed a go-around. The pilot conducted a second approach, during which he held an airspeed of 60 to 70 knots on the final approach, with full flaps. The pilot reported that the airplane touched down in the vicinity of the approach end of the runway. The airplane bounced followed by a second touchdown. The pilot stated that he applied brakes and that the brakes locked up. The airplane overran the end of the runway, across grass and came to rest on a road. A Federal Aviation Administration Inspector (FAA) interviewed the pilot at the accident site. The pilot reported that he flared mid-field, and that touchdown occurred on the last third or quarter of the runway. The FAA Inspector conducted a telephone interview with the two passengers on board the airplane. One passenger, a student pilot, stated that on his second approach, the pilot was high and continued to float while flaring, "experiencing ground effect." He also stated, the airplane departed the runway, onto the grass, and slide across the road. Examination of the airplane by FAA Inspectors revealed no preimpact failure of the engine or airframe. The FAA Inspector's report stated, " I disassembled the left and right brake assemblies, the brake pads were found within limits and found no reason as to why the brake system should not perform normally."