The visual inspection, whether aided or not, is a first line of defence to identify potential or existing failure based on visible surface features. Forensic analysis is an integral part of the NDT process to better understand where to look for the causes of failure. Better magnification and light can assist in detecting surface cracks and an understanding of material behaviour can guide the inspection process. Materials subject to temperature and pressure applications may exhibit varying degrees of stress and strain, resulting in cracks and deformation which can lead to failure. Using metallurgical microscopes allows the investigator to determine, forensically, what the mode of failure may have been.