Optical 3D scanners are suited for quality control of complex freeform surfaces. Therefore, they are used to inspect airfoils of aircraft engines, terrestrial gas & steam turbines and turbocharging systems. Many turbine blades are manufactured in casting, forging, milling and grinding processes. In quality control, GOM systems support the introduction of new products as well as the inspection and final acceptance in various production technologies. Color deviation maps as well as 2D and 3D analyses of shape, position and thickness help to draw conclusions about manufacturing effects. 3D metrology also accelerates maintenance, service and upgrading of turbines: by identifying faulty spots or parts to be replaced, controlling the material coating as well as inspecting the post-processing.