Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to General Electric Company (GE) CF6 series turbofan engines, that currently requires initial and repetitive ultrasonic and eddy current inspections of high pressure compressor rotor (HPCR) stage 3-9 spools for cracks. This action would define more aggressive inspection intervals for certain HPCR stage 3-9 spools, add CF6-80E1 engines to the inspection program, add inspection requirements for spools manufactured from 8 inch diameter billet, add a one-time inspection of the stage 3-5 blade slot bottoms, and add a one- time inspection of the web and hub-to-web transition areas. This proposal is prompted by analysis of recent HPCR stage 3-9 spool inspection results and separations, and assessment of the adequacy of the existing program to prevent HPCR stage 3-9 spool cracking and separation. As a result of that assessment, the FAA has determined there is a need to make changes to the existing AD. The actions specified by the proposed AD are intended to prevent HPCR stage 3-9 spool cracking and separation, which can result in an uncontained engine failure and aircraft damage.