Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9, DC-9-80 and C-9 (military) series airplanes, and Model MD-88 airplanes. This proposal would require either installation of external protective doublers between the outboard flight spoiler actuators and the aft spar webs of the wings, or replacement of the pistons of the outboard flight spoiler actuators with improved pistons. This proposal is prompted by reports of failure of the piston of the outboard flight spoiler actuator due to fatigue at the clevis end of the upper lug mounting hole of the piston. The actions specified by the proposed AD are intended to prevent such failure of the piston and the consequent puncturing of the aft spar web. This condition, if not corrected, could result in fuel leakage and reduced structural integrity of the wings.