Event Description
During the pushback procedure, the aircraft was pulled forward slightly to remove the nosewheel from the chocks. At that moment, the left main landing gear collapsed.
Inspection Findings
Subsequent inspection of the landing gear assembly revealed a fracture of the forward trunnion bearing support fitting (part number 65-16206-11). Heavy surface corrosion was observed on the fitting. Microscopic examination disclosed extensive intergranular stress corrosion. A crack had developed approximately 0.1 inches inboard from the forward edge of the bore and had propagated approximately 2.1 inches aft into the bore surface. The final fracture resulted from ductile separation.