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

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-300, -400, and -500 series airplanes. This AD requires replacing certain aileron/rudder trim control modules with an improved module that contains an improved rudder trim switch that precludes the problems of sticking associated with the existing switch. This amendment is prompted by reports of sticking conditions in the rudder trim switch. The actions specified by this AD are intended to prevent such sticking, which could result in uncommanded movement of the rudder and consequent deviation of the airplane from its set course.