Cessna 310R N3UR accident near Mcgrath, Alaska

Probable cause

A failure of the right main landing gear bellcrank lower arm fork, bellcrank, pivot bolt, and trunnion bellcrank lug for undetermined reasons.

NTSB analysis

The pilot back-taxied the airplane for departure and then began a 180° left turn to align the airplane with the runway centerline when the right main landing gear collapsed. The gear collapse resulted in substantial damage to the right elevator.

A postaccident examination of the airplane revealed fractures to the bellcrank lower arm fork, bellcrank, pivot bolt, and trunnion bellcrank lug at the right main landing gear, which all displayed signatures consistent with overstress. The airplane had recently been repaired following another right main landing gear failure. During the repair the accident pilot, who was also the mechanic, adjusted the down lock tension as required by the maintenance manual and returned the airplane to service after he determined that the tension was within limits. A statement from the airplane manufacturer suggested that the failure may have been the result of an improper down lock tension adjustment. However, there was insufficient evidence in the investigation to show whether the pilot performed the adjustment incorrectly, thus the cause of the landing gear failure is undetermined.

Text from the NTSB. Open the NTSB docket for WPR22LA124 for the full record.