On July 12, 2001, at 1510 central daylight time, a Young RV-6 homebuilt experimental airplane, N6GY, was substantially damaged when it impacted a tree and house trailer during a forced landing following a loss of engine power while on approach to the David Wayne Hooks Memorial Airport near Spring, Texas. The airplane was registered to and operated by the pilot/builder. The private pilot, sole occupant, sustained minor injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 test flight. The local flight originated from the David Wayne Hooks Memorial Airport at 1429. This was the first flight of the homebuilt airplane following its certification on July 11, 2001. The pilot reported that while returning from the airplane's maiden flight, about 10 nautical miles from the airport, approximately 1,200 feet msl, he turned the electric fuel pump on for landing, and the engine began to run "rough." He then turned the fuel pump off and the engine "smoothed out." He further reported that with the fuel pump on, he could lean the mixture and get the engine to "smooth out." After trying several combinations of fuel pump and mixture settings, the pilot thought the engine was running smooth and planned for a tight pattern, high speed approach, with the mixture full rich and the fuel pump off. While on base for runway 17R, at approximately 600 feet agl, the aircraft appeared to be settling faster than anticipated. The pilot attempted to add power, but the engine was "dead and just wind milling." He went through a "quick restart," and at approximately 400 feet, initiated a forced landing to a nearby trailer park and declared an emergency. The airplane touched down between two rows of house trailers, and during the landing roll, the right wing impacted a tree. The airplane came to rest upright with the left wing against a house trailer. An examination of the airplane by the FAA inspector, who responded to the accident site, revealed that the one piece wing was partially separated from the fuselage, and the left side of the fuselage was torn open. Further examination of the engine and fuel system did not reveal the reason for the loss of engine power.