On September 5, 2003, about 1830 eastern daylight time, an unregistered amateur built Avid Flyer, was substantially damaged during a collision with terrain, while departing a private airstrip near Covington, New York. The certificated private pilot and passenger sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. The pilot stated that he departed on runway 25, an 800-foot-long, 60-foot-wide, turf runway. Prior to the takeoff roll, the airplane was not aligned with the runway centerline. The pilot further stated: "...used some of the runway to get on centerline. On takeoff roll I used more runway than normal. Once we were airborne it was too late to abort the takeoff and we found the [altitude] was not enough to clear trees off the end of the runway." The pilot increased the airplane's pitch angle and cleared the trees. However, the airplane subsequently experienced an inadvertent stall, and impacted a grass field beyond the trees. The pilot did not report any pre-impact mechanical malfunctions with the airplane. The wind was reported as calm, at 1754 and 1854, at an airport approximately 20 miles southeast of the accident site.