Airworthiness Directives; Pratt and Whitney PW4000 Series Turbofan Engines

This amendment supersedes an existing airworthiness directive (AD) that is applicable to Pratt and Whitney (PW) model 4000 series turbofan engines. That action required PW4000 engines with potentially reduced stability margin to be limited to no more than one engine on each airplane, and required removing engines that exceed high pressure compressor (HPC) cycles-since-overhaul (CSO) or cycles-since-new (CSN) from service based on the engine's configuration and category. That action also required establishing a minimum build standard for engines that are returned to service, and performing cool-engine fuel spike testing (Testing-21) on engines to be returned to service after having exceeded HPC cyclic limits or after shop maintenance. This amendment establishes requirements similar to those in the existing AD being superseded, and introduces a rules-based criterion to determine the engine category classification for engines installed on Airbus A300 airplanes. This amendment also adds requirements to manage the engine configurations installed on Boeing 747 airplanes, and requires that repetitive Testing-21 be performed on certain configuration engines. This amendment also establishes criteria that requires Testing-21 on certain engines with Phase 0 or Phase 1, FB2T, or FB2B fan blade configurations. In addition, this amendment re- establishes high pressure compressor (HPC)-to-high pressure-turbine (HPT) cycles-since-overhaul (CSO) cyclic mismatch criteria, and adds criteria to address engine installation changes, engine transfers, and thrust rating changes. Also, this amendment establishes criteria to allow engine stagger without performing Testing-21 for engines which are over their respective limits. This amendment also introduces new requirements on the Phase 3, first run subpopulation engines which were identified after the issuance of NPRM Docket No. 2000-NE-47-AD. The Phase 3, first run subpopulation engines have a significant increase in surge rate and Testing-