Incident Overview
During landing rollout on a Dutch-registered Boeing 767-300 ER, the flight crew applied the brakes and noted a significant airframe vibration accompanied by a pronounced rumbling noise. A post-incident inspection conducted by maintenance personnel discovered a broken landing gear pivot pin on the right main landing gear truck.
Inspection Findings
The landing gear bogie pivot pin was removed from the incident airplane's main landing gear bogie beam. Residual dried grease was observed on the fractured pivot pin and associated bogie beam bushings. A senior materials engineer from the NTSB's Materials Laboratory reported that most of the chromium plating was missing from the pin's shank. The underlying steel was worn, corroded, and displayed signs of heat damage. The originating fracture region contained corrosion pits, and the fracture features were noted as typical of stress corrosion cracking.
Flight Data Recorder Analysis
The airplane's flight data recorder (FDR) indicated that the incident landing was within normal operating tolerances, suggesting the landing itself did not contribute to the pin failure.
Service Bulletin
On April 8, 2004, Boeing Commercial Airplane Group issued Alert Service Bulletin 767-32A0199. The bulletin requires the replacement of the current pivot pins with pins made of a different type of steel. According to Boeing, the new steel is more resistant to heat damage and less susceptible to stress corrosion cracking.