Accident Summary
During the landing phase of a personal flight, the private pilot reported that the airplane turned abruptly to the left and departed the side of the runway. The landing gear subsequently encountered muddy terrain, causing the nose landing gear to collapse.
Investigation Findings
An NTSB materials engineer examined the nose gear support structure and determined that the right nose gear attachment foot had fractured at the right engine support mount. The fracture was attributed to fatigue failure.
Service Bulletin Compliance
The airframe manufacturer had issued a service bulletin recommending increased inspection of the failed area due to a history of cracking. The bulletin had reportedly been complied with approximately 18 service hours prior to the nose gear failure. However, portions of the failed component had not been completely stripped of paint as recommended to facilitate crack detection.
Manufacturer Actions
The existing service bulletin was superseded by a revised bulletin that reduced the inspection intervals. Additionally, the manufacturer developed a replacement part that, when installed, eliminates the need for repetitive inspections of the failed component. The old-style component is no longer available as a replacement part.