On December 8, 2000, at approximately 1245 mountain standard time, a Thomas VP-1 homebuilt airplane, N89KD, was destroyed when it impacted the ground during a forced landing near Salt Lake City Municipal 2 Airport, West Jordan, Utah. The pilot received serious injuries. The pilot/builder was operating the airplane under Title 14 CFR Part 91. Visual meteorological conditions prevailed. No flight plan had been filed for this local personal flight that was originating at the time of the accident. The pilot said he was flight-testing the newly finished homebuilt airplane. The original plans called for a fixed pitch propeller. The pilot said that he had put a manually adjustable pitch propeller on the airplane, and he had adjusted it for cruise flight. He said that once he was airborne, the engine began "lugging," and it quickly lost power. He started a right turn to crosswind, and simultaneously began to perform a forced landing. Subsequently, the airplane struck a building and some transmission wires. The airplane came to rest upright. Postaccident examination of the engine by an FAA inspector revealed that the spark plugs were wet with fuel. The inspector also found heavy carbon deposits in the exhaust stack.