Summary
The Federal Aviation Administration (FAA) proposes to supersede an existing airworthiness directive (AD), that is applicable to Pratt & Whitney PW4000 series turbofan engines. That AD currently 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 proposal clarifies inspection requirements for cracking of high pressure compressor (HPC) front drum rotors that have fewer than 1,000 cycles-since-new (CSN). This proposal is prompted by comments from operators seeking more clarity about the inspection requirements of paragraph (a)(1) of the current AD. The actions specified in the proposed AD are intended to prevent HPC drum rotor failure from cracks that could result in an uncontained engine failure and damage to the airplane.