Airworthiness Directives; McDonnell Douglas Model DC-8-61, DC-8-61F, DC-8-63, DC-8-63F, DC-8-71F, and DC-8-73F Airplanes

We are adopting a new airworthiness directive (AD) for certain McDonnell Douglas Model DC-8-61, DC-8-61F, DC-8-63, DC-8-63F, DC-8-71F, and DC-8-73F airplanes. For certain airplanes, this AD requires non- destructive testing (NDT) to detect cracks of the door jamb corners of the forward and aft service doors, and doing applicable related investigative and corrective actions. For certain other airplanes, this AD requires inspecting and repairing if necessary or replacing previously repaired door jamb corners with an applicable repair. This AD results from reports of numerous cases of cracks in the skin at the door jamb corners of the forward and aft service doors. We are issuing this AD to detect and correct fatigue cracking of door jamb corners of the forward and aft service doors, which could adversely affect the structural integrity of the airplane.