Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2008-17-51, which was sent previously to all known U.S. owners and operators of MD Helicopters, Inc. (MDHI) Model MD900 helicopters by individual letters. This AD requires, before further flight, fluorescent magnetic particle inspecting the aft threads of the forward directional control cable (control cable) for a crack and replacing the control cable with an airworthy part if you find a crack. If you do not find a crack, this AD requires that you demagnetize the cable threads until you reach a certain gauss level. This AD also requires visually inspecting the aft cable attach bracket for a crack and for interference with movement of the control cable or for deformation of the aft cable attach bracket. If a crack or interference with movement of the control cable or deformation of the aft cable attach bracket exists, this AD requires replacing the bracket with an airworthy part. This AD also requires modifying the control cable conduit and the rotating cone control rod and identifying the rotating cone control rod with a certain part number. This amendment is prompted by three reports of in-flight failure of the control cable and loss of yaw control resulting in emergency landings and subsequent damage to the helicopter. The actions specified by this AD are intended to prevent loss of yaw control and subsequent loss of control of the helicopter.