Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan Engines

This amendment supersedes an existing airworthiness directive (AD), that is applicable to Pratt & Whitney PW4000 series turbofan engines. That AD requires operators to perform initial and repetitive inspections for cracking of high pressure compressor (HPC) front drum rotors based on cycle usage. That AD also requires the removal from service of any cracked HPC front drum rotors. This amendment clarifies inspection requirements for cracking of HPC front drum rotors that have fewer than 1,000 cycles-since-new (CSN). This amendment is prompted by comments from operators seeking more clarity about the inspection requirements of paragraph (a)(1) of that AD. The actions specified by this AD are intended to prevent HPC drum rotor failure from cracks that could result in an uncontained engine failure and damage to the airplane.