Event Description
As the aircraft rotated during takeoff, the left inboard main landing gear wheel separated from the aircraft. Post-flight inspection confirmed that the axle nut remained secured on the end of the axle, limiting the potential mechanisms for wheel detachment to a fracture of the wheel or bearing failure.
Investigation Findings
Examination of the damaged components revealed significant damage to both bearings and no pre-existing cracking or defects on the fractured hub pieces. This evidence supported bearing failure as the initiating event. The hub fracture was assessed as secondary, resulting from abnormal loading during continued wheel rotation with collapsed bearings. The bearing failure allowed the wheel to move axially outward, pass over the axle nut, and separate once it was no longer restrained on the landing gear axle.
Possible Causes of Bearing Failure
The investigation noted that a bearing failure may have resulted from various initiating factors, including material or manufacturing defect, improper installation, insufficient lubrication, corrosion, material fatigue, or contamination by foreign material. However, the condition of the bearing races and retained bearing fragments did not provide clear evidence as to an initiating event for the failure.
Maintenance History
Maintenance records indicated that the wheel was installed and maintained in accordance with relevant maintenance instructions, and there was a history of bearing component replacement. All components were inspected during an overhaul on 26 November 2025 prior to installation on VH-VEZ, and the wheel had subsequently completed 271 cycles on that aircraft. These factors opposed the failure being the result of an installation or maintenance error.