On May 20, 1996, about 0945 mountain daylight time, N94AT, a homebuilt Tilbert Baby Great Lakes airplane, operated by the owner/pilot, was substantially damaged during landing rollout in Stevensville, Montana. The commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The personal flight was conducted under 14 CFR 91. The pilot reported that the accident flight was his first flight in the homebuilt airplane. The airplane was a sport bi-wing. He stated: "After landing, on rollout, I got a wind gust from the left. The airplane weathervaned into the wind and got the left main gear off the pavement. I over-corrected to the right and when the left gear came back up on the pavement the airplane hopped a couple of times, folding the left gear and wrinkling the left wing tip." No preimpact mechanical malfunctions were reported by the pilot. In the "Recommendation" section of NTSB Form 6120.1/2 (attached), the pilot stated: "Become more familiar with aircraft flight and landing characteristics."