Airworthiness Directives; Eurocopter France Model SE 3130, SE 313B, SA 315B, SE 3160, SA 316B, SA 316C, SA 3180, SA 318B, SA 318C, and SA 319B Helicopters

This amendment adopts a new airworthiness directive (AD) for Eurocopter France (ECF) Model SE 3130, SE 313B, SA 315B, SE 3160, SA 316B, SA 316C, SA 3180, SA 318B, SA 318C, and SA 319B helicopters with a certain main gearbox (MGB) installed. This action requires inspecting the magnetic plug for magnetic particles at specified intervals in addition to the MGB inspections currently required. This AD also requires, within 50 hours time-in-service (TIS), dye-penetrant inspecting the MGB bevel gear for a crack, and if a crack is found, replacing the cracked bevel gear with an airworthy bevel gear before further flight. This amendment is prompted by an MGB failure due to a cracked bevel gear. This condition, if not corrected, could result in failure of the MGB, loss of the main rotor drive, and subsequent loss of control of the helicopter.