Airworthiness Directives; Rolls-Royce Corporation (Formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) (RRC) 250-B and 250-C Series Turboshaft and Turboprop Engines

The FAA is superseding an existing airworthiness directive (AD) for RRC 250-B and 250-C series turboshaft and turboprop engines. That AD currently requires a onetime inspection of the fuel nozzle screen for contamination, and if contamination is found, inspection and cleaning of the entire aircraft fuel system before further flight. That AD also requires replacing the fuel nozzle with a new design fuel nozzle, at the next fuel nozzle overhaul or by June 30, 2006, whichever occurs first. This AD requires the same actions, but would add additional part numbers (P/Ns) to the list of affected fuel nozzles. This AD would also explain that the existing AD, as worded, allows certain part number (P/N) fuel nozzles back into service. Those fuel nozzles must not be allowed back into service. This AD is prompted by the discovery that several P/Ns of fuel nozzles were inadvertently left out of AD 2004-24-09. We are issuing this AD to minimize the risk of sudden loss of engine power and uncommanded shutdown of the engine due to fuel contamination and collapse of the screen in the fuel nozzle.