Summary
We propose to adopt a new airworthiness directive (AD) for Pilatus Aircraft Ltd. Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/ 350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1- H2, PC- 6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as certain combinations of the aileron counterweight and the attaching parts possibly resulting in reduced thread engagement and leading to disconnection of the aileron counterweight from the aileron. We are issuing this proposed AD to require actions to address the unsafe condition on these products.