Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 747 series airplanes. This proposal would require repetitive inspections of the nacelle strut-to-wing attachment structure, and repetitive overhaul of the diagonal brace and spring beam load paths, to maintain damage tolerance requirements and ensure long-term structural integrity; and follow-on and corrective actions if necessary. This action is necessary to ensure the structural integrity of the strut-to-wing load path and prevent separation of the strut and engine from the airplane. This action is intended to address the identified unsafe condition.