Circumstances:
The pilot reported that following a normal landing the aircraft was taxied for some distance. During a left turn the right main landing gear collapsed, resulting in the right propeller and wing contacting the ground. Investigation revealed that the right main gear strut had failed at the lower welded joint. A metallurgical examination determined that the failure was due to the propagation of a fatigue crack along the weld. A weld repair had been effected in the area previously because of a crack and it appeared the crack was not completely removed during the repair procedure. This was not positively confirmed as the owner would not permit destructive testing of the component. The manufacturer's service manual limits repair of the main landing gear to replacement of parts.
