Airworthiness Directives; Agusta S.p.A. Model AB412 Series Helicopters

This amendment adopts a new airworthiness directive (AD) for the Agusta S.p.A. (Agusta) Model AB412 Series helicopters. This action 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. This AD also requires modifying certain blades by installing shear pins and tip closure rivets on all affected blades. This amendment is prompted by reports of in-flight loss of tip blocks and tip closures resulting in minor to substantial damage. The actions specified in this AD are intended to prevent loss of the tip block or tip closure, loss of a blade, and subsequent loss of control of the helicopter.