On February 13, 2004, about 1540 Pacific standard time, a Cessna 172N, N5107K, experienced a partial loss of engine power during takeoff from runway 24 at the Cable Airport, Upland, California. The pilot aborted the takeoff and attempted to stop on the available runway. The airplane sustained substantial damage when it overran the runway's departure end, impacted a flatbed trailer, and came to rest on uneven terrain against a berm about 43 yards from the runway. Cable Air, Inc., operated the airplane. The private pilot and one passenger sustained minor injuries; the second passenger was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the local area personal flight. The flight was performed under the provisions of 14 CFR Part 91, and it was originating at the time of the mishap. In the pilot's completed "Aircraft Accident Report," NTSB Form 6120.1/2, he indicated that prior to taking off he performed a preflight inspection of the airplane. He performed a runup and determined that the airplane was in proper working condition and worthy of flight. During the takeoff roll, the pilot again observed that the engine instruments were still "looking good." However, after climbing for several seconds the pilot heard the engine lose power. According to the pilot, he observed that the engine's tachometer had decreased to 1,400 rpm, and he opined that the airplane was not going to continue flying. Therefore, he aborted the climb and lowered the wing flaps. Cable Airport management personnel verbally reported to the National Transportation Safety Board investigator that skid marks were noted on the departure end of the runway leading to the accident airplane. There were about 156 feet of skid marks on the runway, which led to 128 feet of skid-like marks in the dirt. Under the direction of the Safety Board investigator, the airplane was recovered from the accident site and was examined under Federal Aviation Administration (FAA) supervision. In summary, the FAA inspector reported that on February 17, the accident airplane's engine was removed from N5107K, and it was installed on another Cessna 172 airframe that was awaiting an engine overhaul. After removing and replacing several impact-damaged components, the engine was run up to 2,400 rpm. With the exception of a minor vibration due to the fact that the crankshaft was bent, the engine operated normally. The reason for the partial engine power loss, as reported by the pilot, was not ascertained.