Airworthiness Directives; Agusta S.p.A. Model A109K2 Helicopters

This amendment adopts a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model A109K2 helicopters. This action requires dye-penetrant inspecting the tail rotor trunnion (trunnion) assembly for a crack at specified intervals, replacing any cracked trunnion with an airworthy trunnion, and reporting any failed trunnion. This amendment is prompted by the report of an accident involving a tail rotor hub and blade assembly separating from the helicopter due to fatigue failure of the trunnion. The cause for the crack in the trunnion has not been determined and is still under investigation. This condition, if not detected, could result in failure of the trunnion, loss of the tail rotor hub and blade assembly, and subsequent loss of control of the helicopter.