On August 25, 2001, approximately 0745 central daylight time, a John Greenlee X-Aircamper homebuilt experimental airplane, N899JG, registered to and operated by the pilot, was substantially damaged during a forced landing following a loss of engine power while in the VFR approach pattern to the Healdton Municipal Airport, near Healdton, Oklahoma. The private pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight originated from Bowie, Texas, at 0645, and was en route to Healdton, Oklahoma. According to information provided by the pilot in the enclosed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the pilot was on downwind at Healdton Airport when he experienced a "loss of power." He attempted to "glide" around to the runway, but a "significant south wind complicated the attempt." The airplane cleared trees "by inches and mushed into the ground", about 100-200 feet short of the runway. The pilot stated that he suspected carburetor ice to have caused the loss of power. According to information on a Carburetor Icing Probability Chart, and the temperature/dewpoint in which the airplane was operating, a "serious icing" probability could have existed. The vintage airplane was powered by a Ford Model "A" engine.