Airworthiness Directives; Boeing Model 737 Series Airplanes

This amendment revises an existing airworthiness directive (AD), applicable to all Boeing Model 737 series airplanes, that currently requires installation of a new rudder control system and changes to the adjacent systems to accommodate that new rudder control system. That amendment would have superseded seven existing ADs; however, this new amendment removes any reference to superseding four of those seven ADs. This new amendment is prompted by an FAA determination that the requirements of those four ADs must remain in effect until installation of the new rudder control system and corresponding changes to the adjacent systems. The actions specified in this AD are intended to prevent an uncommanded rudder hardover event and consequent loss of control of the airplane due to inherent failure modes, including single-jam modes, and certain latent failures or jams combined with a second failure or jam.