On February 15, 2017, about 1834 Pacific standard time, a Beechcraft F33A, N222EN, was substantially damaged when it was involved in an accident near Pomona, California. The pilot received minor injuries and the passenger was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal cross-country flight. The pilot reported that he was on a cross-country flight from Selma Airport (0Q4), Selma, California, to Cable Airport (CCB), Upland, California. During cruise flight, the engine lost power and the pilot made an emergency landing to the Pomona Fairplex Fairgrounds, Pomona. The pilot reported that he had filed a visual flight rules (CFR) flight plan. He estimated that he had 40-45 gallons of fuel on board the airplane at the time of the forced landing. According to the pilot's written statement, about 10 miles from his destination the Southern California (SoCal) approach controller terminated radar services with the pilot. Up to that point, and a little beyond, the flight had been uneventful. The pilot reported that close to the north boundary for Brackett Field Airport (POC), Laverne, California, Class D airspace, the engine without warning "stumbled, shuddered, and stopped making power." The pilot attempted to troubleshoot the engine without success. He further stated that he noticed a drop in manifold pressure, but the engine didn’t completely quit. He then decided to divert to POC and set up for an emergency landing. The pilot radioed his intent and the POC controller cleared him to land. The pilot knew there was a drag strip and parking lot close to POC, and as he approached the airport, he realized he wasn’t going to make the runway. He set up to land off airport at the fairgrounds; he lowered the landing gear and because of the darkness he couldn’t see exactly where to land. The airplane struck a fence and a seating area. The main landing gear was sheared off and the right-wing leading edge was damaged. After he exited the airplane, he reported a fuel leak. An engine examination and engine test run were performed with no mechanical anomalies that would have precluded normal operation and production of horsepower. The engine remained attached to the airframe and the three-bladed propeller remained attached at to the propeller hub and engine. The left side of the engine induction and exhaust systems exhibited impact damage. The mixture control vapor return fitting had broken. The top spark plugs were removed and exhibited normal operating signatures. The cylinders were borescoped with no anomalies noted. The fuel pump was removed, and the drive manually rotated with no binding; the drive coupling was intact. To facilitate the engine-run, the left side induction system was replaced, and the left side exhaust was removed. The fuel pump and spark plugs were reinstalled and the broken fitting for the mixture control was replaced. The engine and airframe were secured for the engine run and an external fuel supply was plumbed to the airplanes fuel system at the left-wing root. After adjustments were made, the engine started normally and allowed to warm up. Once the engine had warmed up, the engine’s throttle was slowly advanced to 2150 rpm. A magneto check was performed at 1200 rpm with a drop of 75 rpm noted for each magneto. Engine instruments were in the green arcs.