Analysis of failed left wheel hub assembly of a microlight aircraft

The failure of the left wheel hub assembly was due to fatigue cracking of the rear half hub. The sharp edges resulting from the fracture were responsible for the deflation of the tyre. Evidences suggest that abnormal forces acted on the outboard surface of the wheel hub resulting in pulling apart of the two hubs. The most probable reason for the generation of such forces appears to be either due to heavy landing or inadequate tyre pressure. This had resulted in digging of the axle flange into the wheel hub with subsequent fatigue crack initiation at these locations. No abnormalities such as over-tightening of the bolts, material defects etc were responsible for the failure