On April 17, 2001, about 0945 central daylight time, a North American AT-6D, N1364N, registered to T-6 Warbirds Inc., and operated by North American Top-Gun Inc., as a Title 14 CFR Part 91 instructional flight, ran off the runway while landing at Destin, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The aircraft incurred substantial damage, and the commercial-rated pilot, and dual student were not injured. The flight originated from Destin, Florida, the same day, about 0915. The flight instructor stated that after a 30-minute familiarization flight, he demonstrated a touch-and-go landing without incident, and remained in the traffic pattern with the intent of performing a full stop landing. He said that his approach to land was normal, but just prior to touchdown with the main landing gear, he encountered wind gusts. He said as the tail of the aircraft began to settle, he encountered a gust from the right front quarter, and the aircraft weather vaned to the right. He said that he applied corrective control input, but insufficient control authority was available to arrest the excursion, and the aircraft exited the runway to the right, into loose sand, resulting in substantial damage to the aircraft. The instructor further stated that prior to the accident there had been no malfunction or failure to the aircraft, or any of its systems.