On June 8, 2024, at 1008 eastern daylight time, an experimental amateur-built Titan T-51 airplane, N512JA, sustained substantial damage when it was involved in an accident near Madisonville, Tennessee. The airline transport pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot, who also built the airplane, stated that after he landed at the Monroe County Airport (MNV), Madisonville, Tennessee, he felt a “violent shimmy” from the tailwheel and the airplane began to veer left. He attempted to steer the airplane with full right rudder and brakes, but the right main landing gear collapsed. The airplane began to exit the runway when the left main landing gear collapsed. The airplane came to a rest just off the runway in the grass. The airplane sustained substantial damage to the right wing and fuselage, and all four composite propeller blades sheared from the hub. Postaccident examination of the airplane revealed the welded joints for the left and right main landing gear had failed and the tailwheel attachment link had fractured. The tailwheel link and the fractured weldments were sent to the NTSB Materials Laboratory for further examination. The examination revealed that the right landing gear weldment fractured during landing from fatigue cracking that had initiated at multiple locations on the outer surface of the weld. The fatigue cracking propagated over time through the weld filler to approximately 1.6 inches in circumference. The remainder of the fracture surface exhibited features consistent with overstress. The fracture surfaces of the left landing gear weldment and tailwheel link were both consistent with overstress. According to the pilot, the weldment made to the right landing gear was not fabricated by the airplane’s kit supplier. It was fabricated about 12 years before the accident flight by a 3rd party welder whom he hired to repair damage from a previous accident. The pilot said that he did not observe any detectable issues with the right landing gear weldment before the accident.