Summary
This document revises an earlier proposed airworthiness directive (AD), applicable to certain Cessna Model 650 airplanes, that would have required repetitive replacement of the horizontal stabilizer primary trim actuator assembly (HSTA) with a repaired assembly. This new action revises the proposed rule by removing the requirement for repetitive replacement of the HSTA; adding a requirement to inspect to determine the part number of the actuator control unit (ACU) and replace the ACU with a new, improved ACU if necessary; and adding a requirement to revise the Limitations section of the airplane flight manual. This new action also revises the applicability to include all Model 650 airplanes. The actions specified by this new proposed AD are intended to prevent uncommanded movement of the horizontal stabilizer, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.