Automated and non-destructive inspection of composite helicopter rotor blades using advanced shearography

Helicopter rotor blades are highly sophisticated products composed of a variety of materials and components. They are safety relevant components and therefore, 100% quality control has to be assured. The French helicopter producer, Eurocopter S.A., Paris, has installed a system for automatic inspection of rotor blades on structural defects. In this system, laser shearography is used as an inspection technique. The rotor blades are positioned in a vacuum chamber and loaded with a relative pressure difference. Bonding and structural defects show up as tiny deformations of the surface and are recorded with two shearography cameras, positioned on both sides of the rotor blade. As this helicopter blade inspection system is the first fully automatic production control system in european aerospace industry based on laser shearography, this application is an important step in bringing shearography techniques into production control. In this paper, the complete inspection system is presented.