Incident Description
During landing, the right main landing gear collapsed. The subsequent investigation examined the landing gear components to determine the cause of the failure.
Investigation Findings
Examination of the landing gear revealed that the rear trunnion pivot pin, part number 5741112-1, had moved aft and out of the trunnion. The pin exhibited approximately one inch of white paint on the end that extended into the flap track area. For comparison, the extension of the rear pivot pin on the left landing gear was measured at half an inch of painted pin extending into the flap track area.
The pivot pin is secured in the trunnion by a roll pin. The aft pivot pin still contained a section of the roll pin within it, and the failure mode of the roll pin was identified as shear. Two additional small fragments of the roll pin remained in the trunnion.
The forward pivot pin showed a wear pattern indicating that the shims had been riding approximately 0.2 inches farther from the pivot pin hole than those on the rear pin. Additionally, the rear pin had grooved wear marks extending from the original wear pattern all the way to the end of the pivot pin.