Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This proposed AD was prompted by an evaluation by the design approval holder (DAH) indicating that the fuselage skin is subject to widespread fatigue damage (WFD). This proposed AD would require modification of the lap joint, including related investigative actions and corrective actions if necessary. This proposed AD also would require repetitive post-modification inspections for cracking of the skin at critical fastener rows, and corrective actions if necessary. We are proposing this AD to detect and correct cracks at the lap joint skin that could link up and result in rapid decompression and loss of structural integrity of the airplane.