Discovery of x-rays by Roentgen gave a new thrust in the field of non-destructive testing in industry and in medical diagnosis. Dr. Godfrey Hounsfield added a new dimension in diagnosis by developing clinical CT-scanner, an advanced application of x- rays. CT-scat has been mainly used for medical diagnosis. Tomographic technique has been successfully used in flaw detection of fibre reinforced parts for past one decade.

CT scanner generates x- ray attenuation measurements which are used to produce computer reconstructed images of any desired part of an object, whose densities are within detectable limits. CT gives density distribution diagram (tomogram) along the cross-section of the object.

For the past seven years we have been using medical CT-scanner to test composites parts fabricated for Advanced Light Helicopter project, where four prototypes are undergoing test flights. CT is also used as an aid for process improvement and damage assessment of critical parts.

This paper includes CT investigation carried out mainly on ROTOR HUB PLATES, TORQUE PLATES and ANTI RESONANCE ISOLATION SYSTEM SPRINGS. These are dynamically loaded critical parts mainly fabricated using epoxy based carbon prepregs. CT investigation is carried out at various stages on these parts like process proving, qualification of the part and inservice inspection of the parts.

This paper is mainly intended to share the experience in application of CT scanner for NDT at various stages of thick laminates made out of carbon epoxy prepreg parts of the Advanced Light Helicopter.