Airworthiness Directives; Bell Helicopter Textron, Inc. Model 205A, 205A-1, 205B, 212, 412, 412CF, and 412EP Helicopters

요약

This amendment supersedes an existing airworthiness directive (AD) for the specified Bell Helicopter Textron, Inc. (Bell) Helicopters. That AD currently requires inspecting each affected tail rotor blade (blade) forward tip weight retention block (tip block) and the aft tip closure (tip closure) for adhesive bond voids, and removing any blade with an excessive void from service. That AD also requires modifying certain blades by installing shear pins and tip closure rivets. This amendment contains the same requirements but expands the applicability to include other part and serial-numbered blades. This AD also clarifies the requirement to re-identify the modified blade by adding "FM" after the part number and also requires dynamically balancing the tail rotor. The existing AD was prompted by five occurrences of missing tip blocks or tip closures resulting in minor to substantial damage. This amendment was prompted by the determination that the AD should apply to other affected part and serial-numbered blades. The actions specified by this AD are intended to prevent loss of a tip block or tip closure, loss of a blade and subsequent loss of control of the helicopter.