Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes powered by GE CF6-80C2 series engines. This proposal would require repetitive inspections and torque checks to find discrepancies of the fasteners that attach the diagonal brace fittings of the lower spar to the inboard engine struts, and modification of the fasteners if discrepancies are found. This proposal also would require eventual modification of all the fasteners, which would end the repetitive inspections and checks. This action is necessary to find and fix discrepant fasteners of the diagonal brace fittings, which could result in reduced structural integrity of the diagonal brace-to-strut attachment, and possible separation of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.