Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires removing certain power turbine rotors from service using a specific drawdown schedule. This AD was prompted by reports of fatigue cracks in the airfoil of the power turbine blades. We are issuing this AD to prevent fracture of the power turbine blade airfoil, which could result in sudden loss of engine power and prevent continued safe flight or safe landing.