On September 3, 2011, about 1140 Pacific daylight time, a Stinson V77, N9112H, sustained substantial damage when its right main landing gear collapsed following a loss of control during taxi for takeoff at Tillamook Airport (TMK), Tillamook, Oregon. The airline transport pilot and two passengers were not injured. Tillamook Air Tours was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the local sight seeing flight. A company flight plan was on file. The pilot stated that he was taxiing on runway 19 with the intent to turn around and take off on runway 01. The wind was a left quartering tailwind, and the first 800 to 1,000 feet of the taxi was uneventful. Suddenly, the airplane rotated over 90 degrees to the left. The right main landing gear collapsed, and the airplane dropped onto its right wing and horizontal stabilizer. The pilot reported that he believed the loss of control was due to a strong gust of wind. Post accident examination of the airplane by a Federal Aviation Administration inspector revealed that the right wing and the horizontal stabilizer were bent, and the fuselage was wrinkled and bent on the left aft lower side and on the right side where the main landing gear joined the fuselage. Additionally, the inspector noted that the right main landing gear pivot bushing, which was made of steel tubing, had cracked longitudinally and split in half, allowing the landing gear leg to separate from the airplane. The inspector noted that some areas of corrosion were present on the landing gear pivot bushing. Pieces of the fractured right main landing gear pivot bushing were examined at the National Transportation Safety Board's Materials Laboratory. The examination found that the fracture features present on the pieces were consistent with overstress fracture. No evidence of preexisting fatigue cracking was found. At 1135, the reported wind at TMK was from 050 at 13 knots. At 1155, the reported wind at TMK was from 050 at 13 knots with gusts to 18 knots.