Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to Pilatus Aircraft Ltd. (Pilatus) Model PC-6 airplanes. The proposed action would require inspecting for loose or sheared rivets in the hinge brackets on the horizontal stabilizer and inspecting for incorrect spacing tolerance of the hinge brackets. If the rivets are found loose or sheared, the proposed AD would require replacing the rivets and also re-positioning the hinge brackets, if found incorrectly spaced. Several reports of rivets shearing on the hinge brackets prompted the proposed action. The actions specified in this proposed AD are intended to prevent structural failure of the hinge bracket on the horizontal stabilizer, which could result in partial or complete loss of control of the horizontal stabilizer and loss of control of the airplane.