Airworthiness Directives; General Electric Company Engines

The FAA is superseding Airworthiness Directive (AD) 2018-03-13 for certain General Electric Company (GE) Model CT7-5A2, CT7-5A3, CT7- 7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, and CT7-9C3 engines. AD 2018-03-13 required initial and repetitive visual inspections and fluorescent penetrant inspections (FPIs) of the main propeller shaft. This AD was prompted by an in-flight failure of a main propeller shaft on a GE Model CT7-9B engine, resulting in the loss of the propeller. This AD requires initial and repetitive visual inspections, FPIs, and ultrasonic inspections (USIs) of the main propeller shaft. Depending on the results of these inspections, this AD requires replacement of the main propeller shaft. As an optional terminating action to these inspections, this AD requires revising the airworthiness limitations section (ALS) of the existing maintenance manual (MM) and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate incorporating the tasks and reduced inspection thresholds for the main propeller shaft. The FAA is issuing this AD to address the unsafe condition on these products.