Accident Overview
On September 30, 2020, at approximately 1940 Alaska daylight time, a Cessna 180H airplane, registration N926LL, was involved in an accident near Tok Junction, Alaska. The airplane, equipped with a tailwheel, was being operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported no injuries, but the aircraft sustained substantial damage.
Landing and Loss of Control
According to the pilot, she was landing on an asphalt runway. After a normal touchdown in the three-point attitude, the airplane began to drift left and right of the runway centerline. Each drift was corrected with light application of the appropriate rudder pedal. As the airplane decelerated, rudder effectiveness diminished, and the airplane veered abruptly to the right. Despite applying left rudder, the pilot could not regain control. The airplane exited the runway, and the left main landing gear separated from the gear box, causing substantial damage to the fuselage.
Maintenance Records
Aircraft maintenance records showed that on September 29, 2020, the day before the accident, the tailwheel had been repaired and the tailwheel bearings replaced.
Postaccident Examination
A postaccident examination of the tailwheel assembly revealed that it rotated freely to the right but was very stiff and difficult to rotate to the left. Disassembly disclosed that the steering arm inside radius (item #13 in the referenced figure) was heavily scored and worn. The compression spring (item #19) had sharp and damaged edges on its ends, and the spacer (item #20 or #21) was missing, which allowed excessive movement of the spring in its assembly. The report included a figure illustrating the Scott 3400 series tailwheel parts.
Conclusion
The accident resulted from a loss of directional control during the landing roll, with the tailwheel malfunction identified as a likely contributing mechanical issue.