Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to BHTC Model 407 helicopters. This proposal would require visually inspecting the vertical fin (fin) for reduced skin thickness; repairing or replacing the fin, if necessary; and identifying fins that have been inspected or repaired. This proposal is prompted by a report of an inboard skin damaged during production. The actions specified by the proposed AD are intended to detect fin assemblies with reduced skin thickness which, if not corrected, reduce the strength of the skin, and could lead to failure of the fin and loss of control of the helicopter.