Airworthiness Directives; Eurocopter France Model AS-350B, B1, B2, B3, BA, and D Helicopters, and Model AS 355E, F, F1, F2 and N Helicopters

This amendment adopts a new airworthiness directive (AD) that is applicable to Eurocopter France Model AS-350B, B1, B2, B3, BA, and D helicopters, and Model AS 355E, F, F1, F2 and N helicopters. This action requires inspecting the tail rotor spider plate bearing (bearing) for the proper bearing rotational torque, axial play, and for any brinelling of the bearing. This amendment is prompted by service difficulty reports citing the need to prematurely replace bearings due to wear, and by two in-flight incidents of increased tail rotor vibration levels due to bearing wear. This condition, if not corrected, could result in seizure of the bearing, loss of tail rotor control and subsequent loss of control of the helicopter.