Failure Analysis of Seized Airframe Bearings

A spherical bearing consisting of a copper-beryllium ball and stainless steel race was seizing during replacement and rework.  An increase in the frequency of the seizures led to a metallurgical analysis of the seized bearings and an audit of all related processing.  It was found that the bearing seizures would occur at various points during the process.  Bearings would seize upon initial installation into the mating fitting, after staking into the fitting, or upon installation of the fitting onto the aircraft.  The variation in scenarios led to many theories that were investigated.  Analysis found that several contributing factors during assembly led to the seizures, including a design change, workmanship, and a lack of clear inspection criteria.  This presentation will provide the background information on the installation, the design change of the bearing, the results of the metallurgical analysis, and the steps taken to prevent repeat occurrences.