The effectiveness of Engine Life Usage Monitoring and Parts Management systems is largely determined by the aircraft-specific requirements. This document addresses the following areas: safety, life-limiting criteria, life usage algorithm development, data acquisition and management, parts life tracking, design feedback, and cost effectiveness. It primarily examines the requirements and techniques currently in use, and considers the potential impact of new technolog to the following areas: parts classification and control requirements, failure causes of life-limited parts, engine life prediction and usage measurement techniques, method validation, parts life usage data management, lessons learned, and life usage tracking benefits. SAE ARP1587 provides general guidance on the design consideration and objectives of monitoring systems for aircraft gas turbine engines. A major function of these Engine Monitoring Systems is to monitor the usage of life-limited parts in order to maximize available life and to enhance aircraft safety. The purpose of this document is to review the current approaches to Engine Life Usage Monitoring and Parts Management. The document also serves to provide a summary of the many varied requirements of aircraft turbine engine life usage monitoring and parts management and a description of the means by which these requirements can be achieved more effectively through the use of engine monitoring systems.