On July 27, 2012, about 1509 eastern daylight time, a Piper PA-24-250, N6248P, was substantially damaged following a loss of engine power and collision with a fence at Montgomery Executive Airport (BCB), Blacksburg, Virginia. The certificated airline transport pilot and three passengers were not injured. The airplane was registered to a private individual and was operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed. The flight originated at Crestview, Florida (CEW) about 1030 central daylight time. The pilot reported that he was approaching the destination airport for landing when the engine began to lose power. He applied carburetor heat; however, this did not improve engine performance. He switched the right fuel selector from the main to the right tip tank. The engine did not recover. Unable to maintain altitude, the pilot attempted a forced landing in the airport parking lot. The airplane touched down in the parking lot and collided with a perimeter fence. A Federal Aviation Administration inspector responded to the accident site and examined the wreckage. The inspector confirmed substantial damage to the wings. The wreckage was recovered to a local maintenance facility where a subsequent examination of the wreckage was performed. The left tip tank contained a residual amount of fuel. The left and right main tanks were empty of fuel. The right rip tank contained about 7.5 gallons of fuel. The airplane was equipped with a Britton fuel tank modification. There were two fuel selector handles; the left handle was in the “L MAIN” position and the right handle was in the “R TIP” position. A placard was installed on the fuel tank selector panel, stating that tip tanks were for use in level flight only. According to the FAA, the pilot stated that his fuel gauges indicated about one quarter full at the time of the accident; however, he was not sure if they were accurate so he relied on his calculations of fuel burn rate during the flight. The flight plan filed by the pilot indicated an en route time of 2 hours and 32 minutes. When the loss of power occurred, the flight had been airborne for about 3 hours and 39 minutes.