Summary
This document proposes adopting a new airworthiness directive (AD) for the specified model helicopters. The AD would require 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 would also require modifying certain blades by installing shear pins and tip closure rivets. This proposal is prompted by five occurrences of missing tip blocks or tip closures resulting in minor to substantial damage to blades installed on Bell Model 212 and 412 helicopters. The actions specified by the proposed 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.