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 AD currently requires interim actions to address engine takeoff power loss events until the high-pressure-compressor (HPC) case is redesigned and available for incorporation on the PW4000 engines. This amendment requires the same actions as that AD, adds on- wing Testing-21 to engines installed on Boeing 747 and MD-11 airplanes, and adds the requirement to install a new Ring Case Configuration (RCC) rear HPC on engines installed in the Boeing fleet as terminating action to the requirements of this AD. This amendment is prompted by the development of an RCC rear HPC for PW4000 series turbofan engines installed in the Boeing fleet. The actions specified by this AD are intended to prevent engine takeoff power losses due to HPC surge.