AD 99-23-03 Amendment 39-11399

This amendment adopts a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron Canada (BHTC) Model 430 helicopters. This action requires verifying the torque on each vertical fin attachment bolt (bolt); modifying the vertical fin and tailboom and replacing the attachment hardware; and re-verifying the torque on the bolts after inspecting the fittings. This amendment is prompted by a report of a loose vertical fin, which was discovered during a post- flight inspection. The actions specified in this AD are intended to prevent loss of torque of the bolts, which could lead to fracture of the bolts, separation of the vertical fin from the helicopter, and subsequent loss of control of the helicopter.