Monograph presents such non-destructive testing methods as visual optical, capillary, magnetic, radiation, eddy-current, thermal and acoustic, which is intended for damage and defect detection of machine parts, assemblies and products. Theory of non-destructive testing methods is set, taking into account their practical applications. Non-destructive testing methods can be widely applied for both scientific and practical purposes in aviation, as well as in other engineering areas – for automotive, rail and marine transportation vehicles, space equipment control, etc. Particular attention is paid to the detection of hidden defects in aviation structural elements and nodes using acoustic emission non-destructive testing method. The monograph is intended for mechanical engineering, transport and aeronautic specialists, aircraft maintenance organizations personnel, researchers, doctoral and graduate students and students of mechanical engineering, transport and aeronautics programs.