AD FAA-2012-1156

We are superseding airworthiness directive (AD) 2000-06-13 R1, which applied to certain The Boeing Company Model 737-200, -200C, -300, and -400 series airplanes. AD 2000-06-13 R1 required repetitively inspecting for cracking of the corners of the door frame and the cross beams of the aft cargo door, and corrective actions if necessary. AD 2000-06-13 R1 also required modifying the aft cargo door, which terminates the repetitive inspections. This new AD adds airplanes to the applicability, adds inspections and related investigative and corrective actions, revises certain inspection types, and reduces a certain compliance time for modifying the doors. This AD was prompted by reports of cracking in the forward and aft corner frames of the aft cargo door and in the lower cross beam. We are issuing 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.