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

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2001-18-51, which was sent previously to all known U.S. owners and operators of Eurocopter France (ECF) Model SA.315B, SA.316C, SA 3180, SA 318B, SA 318C, SA.319B, SE.3160, and SA.316B helicopters by individual letters. This AD requires, within 10 hours time-in-service (TIS), inspecting the magnetic drain plug and the main gear box (MGB) filter for a rust- colored deposit, inspecting the MGB to determine the angular displacement on the MGB output flange, and periodically examining oil samples. If a rust-colored deposit is found on the drain plug or filter, if the oil is rust-colored, or if the angular displacement is 1 millimeter (0.039 inch) or more, this AD requires replacing the MGB with an airworthy MGB before further flight. Repairing or overhauling the gearbox, or re-identifying certain gearboxes that have already been appropriately overhauled, is terminating action for the requirements of this AD. This AD is prompted by an accident of an ECF Model SA.315B helicopter that lost power to the tail rotor. The loss of power to the tail rotor was due to wear of the splines of the output bevel drive pinion in the MGB. The actions specified by this AD are intended to prevent a loose splined coupling, spline wear, loss of power to the tail rotor, and subsequent loss of control of the helicopter.