On February 28, 2025, about 1058 Hawaii-Aleutian standard time, a Gippsland GA-8 airplane, N699AV, was substantially damaged when it was involved in an accident near Lihue, Hawaii. The pilot and four passengers were not injured; one passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 air tour flight. The pilot reported that he made a normal approach with full flaps and landed on runway 21 at the Lihue Airport. While taxiing to parking he made a slow right turn off the runway. As the pilot straightened the airplane out of the turn on to the taxiway, the right landing gear leg collapsed, resulting in substantial damage to the fuselage. The right main landing gear fractured at the upper end of the bend near the fuselage attachment point; the right main gear then separated from the airplane. Postaccident examination revealed discoloration and offset grain structure on the fractured gear leg with a 45° shear lip on the right separated gear leg. The left gear leg had a crack in the same location as the failed gear leg. The airplane’s service manual required the landing gear to be inspected visually every 100 hours or during the annual maintenance inspection. The main landing gear had a total of 13,299.2 flight hours. Further examination by the NTSB Materials Laboratory revealed the right main landing gear leg was fractured near the middle of the bend at the upper end of the leg. The outboard side of the fracture was damaged from contact with terrain. The inboard side was relatively undamaged. A flat area with dark features and a curving boundary was observed on the lower side of the fracture, with features consistent with fatigue. Radial marks in the fatigue region emanated from a corrosion pit in the lower surface. Oxides and corrosion pits were observed on the lower surface adjacent to the fracture surface, and paint covering adjacent areas was bubbled, consistent with the presence of underlying corrosion damage. The remainder of the fracture was primarily in the transverse plane and had a mostly matte gray appearance with small shear lips at the edges, features consistent with overstress fracture in the steel tubular section. The plane of fracture changed at the upper side of the fracture consistent with the final segment of fracture from bending loads.