The NTSB has issued a Safety Recommendation calling for the development of nondestructive testing techniques for Robinson main rotor blades after approximately 596 hours time-in-service to check for bond defects in areas between the skin and spar at the tip of the blade and between the skin and tip cap on all R22s and R44s. The Board also wants stricter inspection of the blades for cracks in the paint layer at the skin-to-spar bondline, and when cracks are found, the NTSB wants the blades removed from service.