AD FAA-2011-0273

We are adopting a new airworthiness directive (AD) for Rolls- Royce Corporation (RRC) AE 3007A, AE 3007A1/1, AE 3007A1, AE 3007A1/3, AE 3007A1E, AE 3007A1P, and AE 3007A3 turbofan engines. This AD requires initial and repetitive eddy current inspections (ECI) of certain 6th-through-13th stage compressor wheel knife edge seals, and initial and repetitive ECIs of the compressor wheel outer circumference, for cracks. This AD was prompted by reports of low-cycle fatigue cracks found during shop visits, in the 6th-through-13th stage compressor wheels having chrome-carbide coated or uncoated knife edge seals. We are issuing this AD to prevent uncontained failure of the 6th-through-13th stage compressor wheel, leading to damage to the airplane.