During exploitation and overhaul of Su-30MKI aircraft, number of cracks are reported from IAF bases and HAL (NK) respectively. At present, visual inspection with/ without magnifying glass and dye penetrant methods are used to identify cracks/ defects on the structure. Sometimes it is difficult to locate the cracks/ defects in inaccessible locations. In few of the cases, the location of the cracks/ defects is accessible only after dismantling of assemblies. In view of the above, an advanced and effective non-contact structural health monitoring system is required to identify cracks/ defects without dismantling of aircraft structure.