Airworthiness Directives; Turbomeca S.A. Arrius Models 2B, 2B1, and 2F Turboshaft Engines

The FAA is revising an existing airworthiness directive (AD) for Turbomeca S.A. Arrius Models 2B, 2B1, and 2F turboshaft engines. That AD currently requires replacing the right injector half manifold, left injector half manifold, and privilege injector pipe. This AD requires the same actions, but relaxes the compliance time for the repetitive replacements on Arrius 2F engines. This AD results from Turbomeca relaxing the repetitive replacement interval for Arrius 2F engine fuel nozzles based on review of returned fuel nozzles to Turbomeca. We are issuing this AD to prevent engine flameout during rapid deceleration, or the inability to maintain the 2.5 minutes one engine inoperative (OEI) rating, and to prevent air path cracks due to blockage of the fuel injection manifolds.