Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 737 series airplanes, that currently requires repetitive inspections to find cracking of the lower skin at the lower row of fasteners in the lap joints of the fuselage, and repair of any cracking found. That amendment also requires modification of the fuselage lap joints at certain locations, which constitutes terminating action for repetitive inspections of the modified areas. This proposed action would add repetitive inspections and would require replacement of the current preventive modification with an improved modification. This proposal is prompted by the FAA's determination that, in light of additional crack findings, certain modifications of the fuselage lap joints do not provide an adequate level of safety. The actions specified by the proposed AD are intended to find and fix cracking of the fuselage lap joints, which could result in sudden decompression of the airplane.