Amateur-built T51 N512JA accident near Madisonville, Tennessee

Probable cause

The failure of the right main landing gear weldment due to fatigue cracking.

NTSB analysis

After landing, the pilot felt a violent tailwheel shimmy and the airplane veered left. He applied full right rudder and brakes, but the airplane continued to veer toward the left edge of the runway. The right main landing gear collapsed, followed by the left main landing gear, and the airplane departed the runway onto the grass. Postaccident examination found that both of the lower main landing gear weldments had fractured, in addition to the tailwheel attachment link. Metallurgical analysis determined that the lower right landing gear weldment failed on landing due to fatigue cracking that originated at multiple locations on the weld and propagated over time. The remaining fracture surfaces on the right landing gear, left landing gear, and tailwheel link showed overstress, most likely due to the landing sequence.

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 weldment before the accident.

Text from the NTSB. Open the NTSB docket for ERA24LA255 for the full record.