ANC20LA100

The pilot stated that after landing, as the airplane decelerated and rudder effectiveness diminished, the airplane veered abruptly to the right. Left rudder was applied but was unsuccessful in controlling the airplane. The airplane exited the runway and the left main gear separated from the gear box resulting in substantial damage to the fuselage. A postaccident examination revealed excessive wear, damage, and a missing component inconsistent with proper tailwheel maintenance occurring the day before the accident.

On September 30, 2020, about 1940 Alaska daylight time, a Cessna 180H airplane, N926LL, sustained substantial damage when it was involved in an accident near Tok Junction, Alaska. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that she was landing her tailwheel-equipped airplane on an asphalt surfaced runway. After a normal touchdown in the three-point attitude, the airplane drifted to the left and right of the runway centerline but was corrected each time with the light application of the appropriate rudder pedal. As the airplane decelerated and rudder effectiveness diminished, the airplane veered abruptly to the right. Left rudder was applied but was unsuccessful in controlling the airplane. The airplane exited the runway, and the left main gear separated from the gear box, resulting in substantial damage to the fuselage. Aircraft maintenance records revealed that on September 29, the day before the accident, the tailwheel had been repaired and the tailwheel bearings replaced. A postaccident examination revealed that the tailwheel rotated freely to the right but was very stiff and difficult to rotate to the left. Disassembly of the tailwheel revealed that the steering arm inside radius (item #13 in figure 1 below) was heavily scored and worn. The compression spring (item #19 in figure 1 below) had sharp and damaged edges on the ends of the spring, and the spacer (item #20 or #21 in figure 1 below) was not present, which allowed for excessive movement of the spring in its assembly. Figure 1 - Scott 3400 series tailwheel parts illustration.