Airworthiness Directives; Pratt & Whitney PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3, and PW4098 Turbofan Engines

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The FAA is adopting a new airworthiness directive (AD) for Pratt & Whitney PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, PW4090-3, and PW4098 turbofan engines, with certain front turbine hub part numbers installed. This AD requires a onetime visual inspection of the anti-rotation slots in the front turbine hub, for a machining nonconformance, and its replacement if the inspection failed. This AD results from a report of a crack found in an anti-rotation slot of a front turbine hub, during overhaul shop inspection. The anti-rotation slot geometry was not machined in conformance with the design drawing during manufacture. We are issuing this AD to prevent uncontained engine failure, damage to the airplane, and injury to passengers.