Airworthiness Directives; McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes, Equipped With a Tail Cone Evacuation Slide Container Installed in Accordance With Supplemental Type Certificate (STC) ST735SO

We are adopting a new airworthiness directive (AD) for McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes, equipped with tail cone evacuation slide containers as specified above. This AD requires modifying the tail cone slide. This AD also requires additional tail cone drops and slide deployments, and repair if necessary. This AD results from several reports of inadvertent tail cone deployments in which the tail cone slide failed to deploy. We are issuing this AD to ensure that the tail cone evacuation slide deploys correctly. Failure of the slide to deploy during an emergency evacuation could result in injury to flightcrew and passengers.