On June 11, 1999, approximately 0945 central daylight time, a Taylorcraft F21 experimental airplane, N2806W, was substantially damaged when it impacted terrain during initial takeoff climb from the Pleasanton Airport near Pleasanton, Texas. The airline transport rated pilot and his passenger were not injured. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight destined for Gainesville, Texas. The flight was originating at the time of the accident. According to the enclosed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the flight departed from runway 16. At 50-60 feet above the ground, the "aircraft was yawed to the left, pitched nose up and pushed to the right." The pilot added that he attempted to correct for the abnormal flight attitude with the flight controls; however, the airplane continued to descend to the right. The left wing and left main landing gear impacted the ground followed by the right main landing gear and propeller. The airplane came to rest upright approximately 400 feet north of the departure end of the runway. According to the pilot, the airspeed indicated 75 knots prior to, and throughout, the incident. The pilot stated that the winds at the time of the accident were from the southeast at 5 knots. According to a written statement provided by the passenger, a "rotational weather phenomenon" was thought to be involved. During a telephone interview conducted by the NTSB investigator-in-charge, the pilot stated that he also thought he might have flown into a "dust devil," but commented that he did not see anything that would have indicated that he was flying into one. According to the pilot, the left wing strut was damaged and the main landing gear carry through structure sustained structural damage. Additional damage was sustained by the propeller. The pilot examined the airplane flight controls and structure and found no anomalies. The pilot had accumulated a total of 17,655.3 flight hours, of which 125 hours were in the same make and model as the accident airplane.