Airworthiness Directives; Turbomeca S.A. Turboshaft Engines

We propose to adopt a new airworthiness directive (AD) for certain Turbomeca S.A. Arrius 2F turboshaft engines with a certain part number oil pump installed. This proposed AD was prompted by cases of deterioration of the gas generator front bearing due to a link loss between the pump driver and the oil pump shaft. This proposed AD would require inspection, and if necessary, replacement before further flight of the oil pump driver assembly and/or the oil pump shaft, or the oil pump itself. We are proposing this AD to prevent link loss between the pump driver and the oil pump shaft, which could lead to an engine in- flight shutdown, forced landing, and damage to the helicopter.