Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-100, -200B, and -200F series airplanes. This proposal would require initial and repetitive inspections to find discrepancies in the upper and lower skins of the fuselage lap joints, and repair if necessary. This action is necessary to find and fix such discrepancies, which could result in sudden fracture and failure of a lap joint and rapid in-flight decompression of the airplane fuselage. This action is intended to address the identified unsafe condition.