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. This action would add requirements for installation of a terminating modification on airplanes equipped with General Electric CF6-80C2 series engines, and repetitive operational checks of the electro-mechanical brake and the cone brake of the center drive unit following accomplishment of the modification. This action also would remove airplanes equipped with Rolls-Royce RB211-524 series engines from the applicability of the existing AD. This proposal is prompted by the identification of a modification that ensures that the level of safety inherent in the original type design of the thrust reverser system is further enhanced. The actions specified by the proposed AD are intended to prevent possible discrepancies that exist in the current thrust reverser control system, which could result in an inadvertent deployment of a thrust reverser during flight.