Airworthiness Directives; Boeing Model 747-200 and -300 Series Airplanes Equipped with General Electric CF6-80C2 Series Engines

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747-200 and -300 series airplanes, that currently requires various inspections and functional tests to detect discrepancies of the thrust reverser control and indication system, and correction of any discrepancy found. This amendment requires installation of a terminating modification, and repetitive functional tests of that installation, and repair, if necessary. This amendment is prompted by the results of a safety review of the thrust reverser systems on Model 747 series airplanes. The actions specified by this 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.