AD FAA-2017-0894

We are adopting a new airworthiness directive (AD) for Model TH-1F, UH-1B, UH-1F, UH-1H, and UH-1P helicopters with a Helicopter Technology Company (HTC) main rotor (M/R) blade installed. This AD requires cleaning and visually inspecting the M/R blades and, depending on the outcome of the inspection, repairing or replacing the M/R blades. This AD is prompted by a report of an M/R blade with a fatigue crack in the grip plate and doublers at the blade retention bolt hole. The actions of this AD are intended to correct an unsafe condition on these products.