Failure analysis of damaged main gear leg left of a helicopter

A failed main gear leg of a helicopter was analyzed. Fractographic study confirmed that the failure of the leg was by fatigue. Multiple fatigue cracks were found to have initiated at the toe of the weld and propagated progressively along the thickness as well as along the circumference of the tubular construction. A general check on the material and the weld did not reveal any obvious abnormalities which could give rise to the fatigue crack initiation. However, this needs to be confirmed by comparing the material, hardness and the microstructure with those of the specification. It is stated that due to lack of information, no analysis could be attempted towards identification of the cause of failure