Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737-300, -400, and -500 series airplanes, that currently requires replacement, with new parts, of the existing actuators or the rod ends on the existing actuators at wing leading edge slat positions 1, 2, 5, and 6. This new action would add a one-time inspection of all the rod ends on the actuators of the wing leading edge slats to determine if vibro-engraving was used to identify the parts, and corrective action, if necessary. This proposal is prompted by reports indicating that vibro-engraving was found on new rod ends during installation; such part markings create stress risers that reduce the fatigue life of the rod ends. The actions specified by the proposed AD are intended to prevent fatigue cracking, which could result in failure of the rod ends, uncommanded deployment of the wing leading edge slat, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.