Incident Description
The pilot reported that shortly after a normal touchdown on a paved runway, the nosegear suddenly collapsed. The aircraft came to a stop on the runway, and there was no further movement.
Examination Findings
An examination of the nosegear assembly disclosed that the nosegear drag link scissors assembly was disconnected. The retaining bolt that connects the two halves of the scissors was missing. With the bolt absent, the scissors halves separated, which allowed the nosewheel to caster freely without directional control from the steering linkage. The nosegear was equipped with an oversized tire, sized 8:50 by 10 inches, and a larger-than-standard nose fork.
Technical Details
The drag link scissors assembly is a critical component that maintains proper alignment of the nosewheel during ground operations. The missing retaining bolt indicates a failure of the fastening mechanism, leading to the loss of structural integrity. The specific cause of the bolt's departure was not determined during the examination. The oversized tire and fork may have contributed to increased stress on the assembly, but no causal link was established in the source.
Conclusion
The nosegear collapse occurred due to the separation of the drag link scissors assembly, which resulted from a missing retaining bolt. The source does not provide a specific probable cause for the incident.