Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes. The proposed action would require inspecting the aileron tie-rod jam nuts for looseness, tightening any loose jam nuts, and installing a locking sleeve on both ends of the aileron tie-rod in the chain-drive of the aileron system. The proposed AD results from an incident where the aileron tie-rod jam nuts on the chain-drive of the aileron system became loose. This caused a differential of aileron control between the pilot's control wheel and the co-pilot's control wheel. The actions specified by the proposed AD are intended to prevent such aileron control differential caused by the aileron tie-rod jam nuts becoming loose, which could result in loss of aileron control and consequent loss of control of the airplane.