Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737 series airplanes, that currently requires a one-time general visual inspection of the seat locks and seat tracks of the flightcrew seats to ensure that the seats lock in position and to verify that lock nuts and bolts of adequate length are installed on the rear track lock bracket, and corrective action, if necessary. This amendment revises the applicability of the existing AD by adding airplanes. The actions specified by this AD are intended to prevent uncommanded movement of the flightcrew seats during acceleration and take-off of the airplane, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.