Non Destructive Testing (NDT) is a set of methods that allows you to characterize the state of integrity of structures or materials, without degrading them, either during of production, either in use or as part of maintenance. The Non-destructive testing technician is a specialist in the techniques and technologies used in this context: penetrant inspection, magnetic particle inspection, ultrasound, X-rays, thermography, eddy currents, etc. He is often attached to the "Quality" department of the aeronautical company and must then certify the good conformity of the parts produced by the company.