On October 15, 2000, about 1340 Alaska daylight time, an experimental, homebuilt amphibious float equipped Weste Avid airplane, N126DW, sustained substantial damage during a forced landing, about 1/2 mile southwest of the Birchwood Airport, Chugiak, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight when the accident occurred. The airplane was registered to the owner, Don Weste, Anchorage, Alaska, and operated by the pilot. The private certificated pilot, the sole occupant, received minor injuries. Visual meteorological conditions prevailed. The flight originated at the Birchwood Airport about 1320. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on October 15, 2000, the pilot reported he was asked by the owner of the airplane to fly the newly built airplane to evaluate its handling characteristics. The pilot owns a similar homebuilt Avid Amphibian. After construction, a forty-hour flight test period is required for non type-certificated airplanes. The pilot said he briefly flew the airplane in the past. To maintain level flight, the pilot said he had to hold the flight control stick to the right and forward of a neutral position. Additionally, he had to hold left rudder pressure to maintain a straight and level flight attitude. The pilot also said that he thought the airplane seemed airworthy. The owner of the airplane asked the pilot to fly one more time before any changes were made to the rigging of the flight controls. The pilot said he operated the airplane on the ground for about 20 minutes and then departed to conduct some touch and go landings. The airplane required the same out-of-neutral positioning of the controls as the previous flight. The pilot made one low pass to runway 19 at the Birchwood Airport, and was following another airplane that had extended its downwind landing pattern. The pilot said he was at 500 feet msl when the engine, a Rotax 582, suddenly quit. The airplane entered an uncommanded right spin. He recovered the airplane from the spin above tree-top level and had insufficient altitude to land at the airport. The pilot made a forced landing in a swampy area with the landing gear in the down position. The right wing struck the ground and broke off. In the Pilot/Operator report (NTSB form 6120.1/2) submitted by the pilot, the pilot indicated that the engine lost compression.