Purpose The purpose of this AECTP is to describe the process known as the Ten Step Method that has been developed to determine the ability of materiel to meet extended life requirements and role and deployment changes. The process is presented in this AECTP@ which is a framework document. The purpose of the document is to acquaint project (programme) managers with the engineering principles involved when evaluating the implications of extended life requirements@ and with the outline of a management tool that systematically addresses the issues to be resolved. The following Annex D leaflets are intended to provide additional guidance for the engineering practitioner when addressing the detailed technical issues. 601 Reverse Engineering 602 Time Compression 603 Incremental Acquisition 604 Physics of Failure 605 Guidance on Information Required for Steps 2 and 3 606 Probabilistic Analysis 607 Role and Deployment Changes Application The process described in this AECTP is applicable to all materiel projects. It is especially applicable to joint NATO materiel projects and multi-national materiel projects. The process is comprehensive and ensures that all appropriate environmental conditions@ design modifications@ possible failure modes and earlier qualification assumptions have been considered. Moreover@ streamlining and early exit criteria are integrated systematically into the process to eliminate unnecessary work. Limitations The application of the process is limited to materiel where life is a function of exposure to environmental stresses.