Airworthiness Directives; Airbus Helicopters

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters (Airbus) Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. This AD was prompted by a manufacturer assessment that determined additional actions are necessary to improve particle detection for main gearboxes (MGBs) with certain planet gear bearings installed. This AD requires repetitively inspecting the MGB bevel wheel and the MGB magnetic plug for particles and prohibits installing an affected MGB unless certain requirements are met. These actions are specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.