On April 7, 2012, about 1430 Pacific daylight time, a Cessna 150H, N6616S impacted trees, and came to rest inverted near Crest Airpark, Kent, Washington. The private pilot, the sole occupant, was seriously injured. The airplane sustained substantial damage. The airplane was registered to an individual, and operated by the pilot under the provision of 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, and no flight plan was filed. The flight originated from Sanderson Field Airport, Shelton, Washington.The pilot reported that the flight was a personal cross-country flight to Kent to visit friends. He stated that he did not recall the events leading up to the accident. A local area witness heard an unusual noise, which drew his attention to the airplane. He observed the airplane flying about 20 feet above the ground, in a 90-degree, right-wing low attitude, when it collided with a tree. The airplane subsequently came to rest inverted alongside a street in a residential neighborhood. The witness responded to the accident site, and reported that there was no fuel leaking from the airplane, and there was no fire. During the postaccident wreckage examination, the engine was prepared for an engine run, which included the use of a header tank in order to start the engine. The engine started and was run to 1,800 rpm for a few minutes before it was shutdown. At the conclusion of the examination, no mechanical malfunctions or failures were revealed with the airframe or engine that would have precluded normal operation. ADDITIONAL INFORMATION The uncontrolled airstrip was adjacent to the street, and the airplane came to rest mid-field of the airport. The nearest weather reporting facility was located at Seattle-Tacoma Airport, Seattle, Washington, approximately 11 nautical miles northwest of the accident site. At 1453, the wind was from 340 degrees at 13 knots.