Abstract for:A Conceptual Model of Real System Age

A major challenge for Department of Defense (DoD) decision makers is deciding when to retire a system.  Often, engineered systems remain operational well beyond their planned retirement date.  The B-52 bomber will continue to operate until 2045 for a total life of 90 years; whereas the DoD retired the F-117 stealth fighter after 25 years.  So, the question becomes are there underlying attributes of engineered systems that affect the aging and if so, how can analysts model the real system age?  Previous research found that attributes such as changeability, interoperability, robustness, and versatility are critical elements to this decision.  This work drew inspiration from other research into the aging of biological systems, software systems, and human aging.  However, the previous work did not capture a method to model and simulate the real system age over time to determine how potential policies impact the real system age.  This paper begins to apply system dynamics as a method to model the real system age of an engineered system.  It captures the causal relationships and presents an initial stock and flow model for some of the critical accumulations in the model to include the real system age, system errors, and capability performance.