Action
Final rule.
Summary
We are superseding Airworthiness Directive (AD) 2002-07-08 for certain The Boeing Company Model 737 airplanes. AD 2002-07-08 required repetitive inspections for cracking of the lower skin at the lower row of fasteners in the lap joints of the fuselage; repair of any cracking found; modification of the fuselage lap joints at certain locations, which terminated the repetitive inspections of the modified areas; and replacement of a certain preventive modification with an improved modification. This new AD adds repetitive inspections for cracking at certain window corner fastener holes, a preventive modification, and repair if necessary. This AD was prompted by the FAA's determination that certain modifications of the fuselage lap joints do not provide an adequate level of safety, and the subsequent discovery of cracks in additional fastener locations in the window belt skin panels, adjacent stringers, and window frames in locations outside the previous inspection area. We are issuing this AD to detect and correct fatigue cracking of the fuselage lap joints and window belt skin panels, which could result in reduced structural integrity and sudden decompression of the airplane.