Summary
This notice revises an earlier proposed airworthiness directive (AD), applicable to CFE Company model CFE738-1-1B turbofan engines, that would have required a one-time dimensional inspection of the curvic coupling tooth profile of certain high pressure compressor (HPC) rotor components to check for machining mismatches in the curvic coupling in specific engines and, if necessary, replacement with serviceable parts. That proposal was prompted by reports of machining mismatches in certain HPC rotor components that may decrease the service life of these HPC parts. This action, based on subsequent material stress testing and analysis by CFE Company, revises the proposed rule by eliminating the dimensional inspection requirement and imposing new, reduced life limits for certain HPC rotor components in all engines. The actions specified by this proposed AD are intended to prevent failure of certain HPC rotor components, which could result in an uncontained engine failure and damage to the airplane.