Airworthiness Directives; Rolls-Royce Corporation Models 250-C30, 250-C40, and 250-C47 Series Turboshaft Engines

Résumé

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) models 250-C30, 250-40, and 250-C47 series turboshaft engines with a third-stage turbine wheel, part number (P/N) 6898663 or P/N 23065843 installed, or a fourth-stage turbine wheel, P/N 6892764 or P/N 23066744, installed. This AD adds an additional life limit for third- and fourth-stage turbine wheels. This AD results from analysis by RRC of failures of third-stage turbine wheels. We are issuing this AD to prevent loss of power, possible engine shutdown, or uncontained engine failure.