Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 777-200 series airplanes. This proposal would require inspections for cracking of the web of the horizontal and sloping pressure decks of the fuselage and certain stiffener splice angles and stiffener end fittings, and repair, if necessary. This proposal would also provide an optional preventative modification, which ends the repetitive inspections. This action is necessary to find and fix cracking of the web of the horizontal and sloping pressure decks, which could result in rapid in-flight decompression of the airplane. This action is intended to address the identified unsafe condition.