On January 27, 2012, about 1210 Pacific Standard Time, a Piper PA-28-140, N15791, impacted an object protruding from the terrain when the pilot landed short of the runway at Chehalis Airport, Chehalis, Washington. The commercial pilot, and the certified flight instructor who was giving him a flight review, were not injured, but the airplane, which was owned and operated by the pilot, sustained substantial damage. The 14 Code of Federal Regulations Part 91 flight review, which departed the same airport about 75 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, who was acting as pilot-in-command because his previous flight review was still current, he was executing a simulated power-off landing as part of his current flight review. Because he failed to manage his glide profile in a manner that allowed him to extend the airplane's glide all the way to the approach end of the runway, and since he elected not to add engine power, the airplane touched down in a grassy area a little over 300 feet short of the runway threshold. The pilot then continued the landing roll over the grassy area, across the threshold, and onto the paved runway surface. Although neither the pilot nor the instructor realized that the airplane had impacted an object, later, after the pilot had returned to his home base, he noticed a dent protruding upward from the top skin of the stabilator. He therefore looked at the underside of the stabilator, and discovered a punctured/torn area that required replacement of stressed skin in an area greater than six inches across. Airport personnel later checked the area off the approach end of the runway, and found a piece of bent over rebar protruding from the terrain just over 300 feet from the runway threshold. Tire tracks in the grass revealed that the airplane's wings had just cleared the rebar and that the main landing gear had contacted the surface about 10 feet past it. The rebar, the top portion of which was painted white, was protruding about a foot and a half above the ground. It had been placed there to mark the location of a portion of a future approach lighting system. According to the FAA Inspector who went to the scene of the accident, the rebar was located about 100 feet beyond the boundary of the Runway Safety Area at the non-controlled airport. The same inspector reported that the flight instructor stated that he did not suggest to the pilot that he add power because it appeared to him that the grassy area was clear, and because he thought the pilot would learn a good lesson by landing short.