Incident Overview
A wheel assembly from the right-hand inboard main landing gear departed the aircraft during the takeoff roll. The flight crew returned to the departure airport, and the aircraft landed without further incident.
Examination Findings
Visual inspection revealed that the outer cone bearing had seized. The bearing race, retainer ring, and axle sustained damage. The inner ring of the outer wheel bearing exhibited deformation, rubbing, cracking, and galling. None of the bearing rollers were recovered.
Metallurgical examination disclosed that the inner wheel bearing had migrated approximately 1.5 inches in the inboard direction. The outer bearing ring showed rub damage on the circumference of the inner and outer diameters, as well as on the bearing cage. The bolt that locked the wheel retaining nut was fractured; however, it could not be determined whether the fracture of the bolt contributed to or was the result of the bearing damage.
Bearing Condition
The inner ring of the outer wheel bearing displayed heat damage and localized melting. The damage pattern "appeared to be more consistent with bearing deterioration caused by inadequate or loss of preloading rather than a bearing seizure event."