Summary
The FAA proposes to revise an earlier proposed airworthiness directive (AD) that applies to all Pilatus Aircraft Ltd. (Pilatus) (also identified as Fairchild Republic Company and Fairchild Heli Porter) Model PC-6 airplanes. The earlier NPRM proposed to require you to repetitively inspect the stabilizer-trim attachment and structural components for cracks, corrosion, and discrepancies and replace any defective part with a new part. The earlier NPRM also proposed to require you to replace all Fairchild connecting pieces with a Pilatus connecting piece. The earlier NPRM resulted from mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Switzerland. This proposed AD would retain the actions from the earlier NPRM and would require you to replace fittings without an index after the part number (P/N) with an improved part. This proposed AD results from incorporating revised manufacture service information to include a procedure for replacingcertain fittings with an improved part and to correct the allowable limits of the actuator attachment hole diameters. This proposed AD also clarifies the applicability. Since this action imposes an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on this additional action.