Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737- 200, -200C, -300, and -400 series airplanes, that currently requires repetitive visual inspections to detect cracking of the corners of the door frame and the cross beams of the aft cargo door, and corrective actions, if necessary. That AD also provides an optional terminating action for certain repetitive inspections. This action would add requirements for repetitive high frequency eddy current (HFEC) inspections, and corrective actions, if necessary. This action also would mandate accomplishment of the previously optional terminating action. The actions specified by the proposed AD are intended to prevent fatigue cracking of the corners of the door frame and the cross beams of the aft cargo door, which could result in rapid depressurization of the airplane.