Model-Based Systems Engineering and TCAS II: Thirty Years Later

Thirty years ago, when the TCAS II modeling effort was undertaken, the notion of model-based design and model-based systems engineering were new concepts. The TCAS II modeling effort demonstrated that creating a formal model of a complex system and doing so in collaboration with a diverse group of application experts was eminently feasible and laid the groundwork for future research. In this retrospective, we revisit the effort in the context of model-based systems engineering, summarize the most relevant lessons learned, and discuss the state of model-based techniques today and steps to the future.