Tail rotor blades of helicopters have a definite service life of the order of 1000 to 1500 hours after which they are withdrawn from service. However, in many cases, the blades appeared sound with no external indications of deterioration. However, for extending the blade life, rigourous NDE checks are to carried out on them. Due to the varied type of materials used such as metals, composites, adhesively bonded regions etc., no single NDE technique is capable of inspecting the blade as a whole. A host of complementary NDE techniques are to be employed. At the authors laboratory, about 10 blades were examined non-destructively. Ultrasonics was used for the examination of the metallic portions including the area around the bolts, real time radioscopy for the metallic, honey comb and composite regions and thermal imaging for adhesively bonded regions. This paper, details the methodologies and procedures developed at the authors laboratory.
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