Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that currently requires tests, inspections, and adjustments of the thrust reverser system. That AD also requires installation of a terminating modification, and repetitive follow-on actions. This action would reduce the repetitive intervals for the follow-on actions. This proposal is prompted by reports indicating that several center drive units (CDU's) were returned to the manufacturer of the CDU's because of low holding torque of the CDU cone brake. The actions specified by the proposed AD are intended to ensure the integrity of the fail safe features of the thrust reverser system by preventing possible failure modes in the thrust reverser control system that can result in inadvertent deployment of a thrust reverser during flight.