Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes. This proposal would require a one-time visual inspection to determine if all corners of the doorjamb of the forward service door have been previously modified. The proposal would also require various repetitive inspections to detect cracks of the fuselage skin and doubler at all corners of the doorjamb of the forward service door, and to detect cracks on the skin adjacent to the modification; and various follow-on actions. This proposal is prompted by reports of fatigue cracks found in the fuselage skin and doubler at the corners of the doorjamb of the forward service door. The actions specified by the proposed AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.