Summary
We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 737-200, -200C, - 300, and -400 series airplanes. The existing AD currently requires repetitive 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. The existing AD also requires a modification to the aft cargo door, which terminates the repetitive inspections. Since we issued that AD, we have received reports of cracking on doors on airplanes that were not included in the existing AD. This proposed AD would add airplanes to the applicability, add inspections and related investigative and corrective actions, and revise certain inspection types. This proposed AD would also reduce the compliance time, for certain doors, to do a modification of the doors. We are proposing this AD 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.