Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 and 767 series airplanes. This proposal would require modification of the core cowl assemblies of the engines. This action is necessary to prevent failure of the core cowl latches during an engine fire, and consequent in-flight separation of an engine core cowl and its strut fire barrier from the airplane. This action is intended to address the identified unsafe condition.