Airworthiness Directives; Rolls-Royce Corporation (Formerly Allison Engine Company) AE 2100 Turboprop and AE 3007 Turbofan Series Engines

This amendment adopts a new airworthiness directive (AD), that is applicable to Rolls-Royce Corporation (formerly Allison Engine Company) AE 2100 turboprop and AE 3007 turbofan series engines. This amendment requires a one-time acid etch inspection of the 2nd stage high pressure turbine (HPT) wheel for evidence of damaged material indicating that a higher probability of cracking in future service exists. If the etch inspection reveals damage, this AD requires replacement of the turbine wheel with a serviceable part. This amendment is prompted by a report of a 2nd stage HPT wheel that was returned from the field with cracks in the aft bore face. The actions specified by this AD are intended to detect and prevent early development of cracks due to low cycle fatigue of the 2nd stage HPT wheel in the aft bore face that can lead to wheel failure, power loss, and possible damage to the airplane.