Airworthiness Directives; Boeing Model 737-200, -200C, -300, and -400 Series Airplanes

This amendment revises an existing airworthiness directive (AD), applicable to certain Boeing Model 737-200, -200C, -300, and -400 series airplanes, that currently requires repetitive visual and high frequency eddy current (HFEC) 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 amendment also mandates accomplishment of a modification to the aft cargo door, which would terminate the repetitive inspection requirements. This amendment revises the compliance time for the terminating modification. The actions specified by this AD are intended to prevent fatigue cracking of the corners of the doorframe and the crossbeams of the aft cargo door, which could result in rapid depressurization of the airplane.