On July 31, 2005, about 1300 central daylight time, a single-engine Cessna 120 tail-wheel equipped airplane, N1703N, was substantially damaged following a loss of control during the landing roll at the False River Regional Airport (HZR), near New Roads, Louisiana. The commercial pilot, sole occupant of the airplane, was not injured. The airplane was registered to a private corporation 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. The cross-country flight originated from the Granbury Municipal Airport (GDJ) near Granbury, Texas, at 0900, and was en route to the Yellow River Airstrip (FD93), near Holt, Florida, with a planned fuel stop at HZR. According to the 5,883-hour pilot, after touching down, at about 45-50 miles per hour (MPH), on Runway 36 (a 5,002-foot by 75-foot asphalt runway), the airplane initiated an uncomanded slow right turn. The pilot corrected with left rudder and the airplane responded back towards the runway centerline. When a small amount of right rudder pedal did not arrest the now left turn, the pilot applied full right rudder pedal to no avail. The left turn continued until the airplane was perpendicular with the runway centerline and began to "hop" on the right main landing gear. On the third "hop" the right main landing gear collapsed, the windscreen broke out, and the right wing tip contacted the edge of the runway. After turning approximately 150 degrees the airplane came to rest in an upright position halfway over the edge of the runway. The pilot reported that anexamination of the airplane revealed that both right wing spars were found broken and the right main landing gear box sustained structural damage. Around 1530, while the pilot was arranging to recover the airplane, a "level three or four thunderstorm" came through the area and "picked the aircraft up and body slammed it on its back" causing further structural damage. The pilot further reported that he held an Airframe and Powerplant (A&P) certificate with Inspection Authorization (IA). After the accident he inspected the flight controls, rudder system, and tail-wheel and was not able to find any anomalies that could have contributed to his loss of control. At 1253, the weather observation facility at Baton Rouge Metropolitan Airport, Ryan Field (BTR), near Baton Rouge, Louisiana, located 20 nautical miles southeast from the site of the accident, was reporting no wind, visibility 10 statute miles, scattered clouds at 4,300 feet, temperature 93 degrees Fahrenheit, dew point 73 degrees Fahrenheit, and barometric pressure setting of 29.93 inches of Mercury.