Airworthiness Directives; Turbomeca Arrius 2F Turboshaft Engines

The FAA is adopting a new airworthiness directive (AD) for Turbomeca Arrius 2F turboshaft engines. This AD requires a one-time removal and inspection of the fuel filter-holder assembly to determine that the fuel control unit (FCU) filter is dimensionally correct. The AD also requires updating the Engine Maintenance Manuals to include a dimensional check of the fuel filter-holder assembly every time the FCU filter element is removed from the fuel filter-holder assembly. This AD results from reports of restricted fuel flow caused by a dimensionally incorrect FCU filter. Ground run testing may not detect the fuel flow limitation. We are issuing this AD to detect a dimensionally incorrect FCU filter that could lead to an undetected limitation of fuel flow, limiting the maximum power available in-flight, which could result in the inability to continue safe flight, avoid obstacles or land safely.