Airworthiness Directives; General Electric Company CT7-5, -7, and -9 Series Turboprop Engines
The FAA is superseding an existing airworthiness directive (AD) for General Electric Company (GE) CT7-5A2, -5A3, -7A, -7A1, -9B, - 9B1, and -9B2, -9C, -9C3, -9D, and -9D2 turboprop engines, with certain part number (P/N) and serial number stage 2 turbine aft cooling plates installed. That AD currently requires a onetime eddy current inspection (ECI) of boltholes in certain P/N stage 2 turbine aft cooling plates. This AD expands the population of affected CT7 turboprop engine models, but reduces the number of cooling plates affected. It also requires a onetime ECI of boltholes in certain P/N stage 2 turbine aft cooling plates with specific serial numbers. This AD results from the manufacturer expanding the list of affected engine models and identifying the affected stage 2 turbine aft cooling plates by serial number. We are issuing this AD to prevent separation of the stage 2 turbine aft cooling plate, resulting in uncontained engine failure and damage to the airplane.