Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 707, 727C, and 727-100C series airplanes, that currently requires repetitive inspections to detect cracking of the main cargo door skin and frames, and repair, if necessary. The existing AD also provides optional terminating modifications. This action would mandate follow-on repetitive inspections of repaired or modified areas for certain airplanes. This proposal is prompted by reports of cracking and/or tearing of the main cargo door outer skin and subsequent failure of the door frame. The actions specified by the proposed AD are intended to detect and correct such cracking and/or tearing, which could result in failure of the door frame and consequent rapid decompression of the airplane.