AD FAA-2010-0494

We are adopting a new airworthiness directive (AD) for International Aero Engines (IAE) V2500-A1, V2522-A5, V2524-A5, V2525- D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 turbofan engines. This AD was prompted by three reports of high- pressure turbine (HPT) case burn-through events, numerous reports of loss of stage 1 blade outer air seal segments, and HPT case bulging. This AD requires initial and repetitive 360 degree borescope inspections of HPT stage 1 blade outer air seal segments for evidence of certain distress conditions. This AD also requires incorporation of improved durability stage 1 blade outer air seal segments at the next exposure to the HPT module subassembly as terminating action to the repetitive inspections. We are issuing this AD to prevent HPT case burn-through, uncontrolled under-cowl engine fire, and damage to the airplane.