Summary
This document proposes adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (BHTC) Model 206A and 206B helicopters, serial numbers (S/N) 0004 through 3906, with two- piece vertical stabilizer (fin) supports (fin supports) installed. This proposal would require inserting a revision into the applicable maintenance manual, verifying the torque on the fin support attachment hardware, inspecting the fin support bracket and vertical fin for paint or gaps, and inspecting the fin support bracket for cracking, and if a crack is found, replacing the two-piece vertical fin support with a one-piece casting support. This proposal is prompted by an accident in which the fin supports failed. The actions specified by this proposed AD are intended to detect improper torque of the fin support attachment hardware, gaps between the fin support bracket and the doubler, painted mating surfaces of the fin supports, vertical fin, and vertical fin inserts (fin inserts), and cracking in the fin supports, to prevent the vertical fin from rotating into the tail rotor, separation of the tail rotor, and subsequent loss of control of the helicopter.