Incident
During taxi for takeoff, the right main landing gear collapsed. The collapse resulted from the failure of the barrel lugs that attach the swinging lever to the main landing gear barrel.
Investigation
Examination of the landing gear determined that the outboard lower lug had fractured. The fracture exhibited a fatigue crack that originated from corrosion pits in the bore of the lug. The bushings for the lower lugs, which had been replaced during overhaul, did not have the proper interference fit. Additionally, during the overhaul, the bushings did not receive the proper application of corrosion preventatives as specified by the manufacturer's procedures.
Additional Inspections
During the investigation, nine landing gears with varying numbers of total cycles since overhaul or manufacture were inspected. The inspections revealed torn or missing rubber sealant used on bushing flanges, corrosion in the lug bores, and corrosion on the lug faces.