On September 7, 2003, about 2010 Alaska daylight time, a wheel-equipped Piper PA-18-160 airplane, N4418Z, sustained substantial damage following a loss of control while maneuvering over a remote off-airport site, located approximately 25 miles southwest of Skwentna, Alaska. The private pilot/airplane owner sustained serious injuries, and the sole passenger sustained minor injuries. The Title 14, CFR Part 91 personal flight operated in visual meteorological conditions without a flight plan. The flight departed from a private airstrip located in Wasilla, Alaska, about 1830. In the NTSB Pilot/Operator Accident Report (form 6120.1) submitted by the pilot, he reported he intended to fly over a 1,200 foot long, gravel-surfaced site before attempting to land. He said that as he maneuvered the airplane for the fly over, he applied 10 degrees of wing flaps, and a "downdraft came over the wings and stalled them both..." Subsequently, the airplane struck the ground in a nose down attitude, and came to rest about 200 feet from the approach end of the intended landing site. The airplane sustained structural damage to the wings, fuselage, and empennage. The pilot noted that weather conditions at the time of the accident were, in part: Sky conditions and ceilings, clear; visibility, 20 statute miles; temperature, 50 degrees F; wind, calm. The pilot stated that there were no preaccident mechanical anomalies with the airplane.