The document presents the development and application of the Mirce Functionability Equation, aimed at predicting the in-service performance of maintainable systems, emphasizing the importance of functionality in engineering. It discusses scientific principles governing functionality, including Newton's laws, and highlights the role of Mirce Mechanics in addressing unanswered functionability questions related to maintenance and operational efficiency. Additionally, it categorizes functionability events as positive or negative based on system states and outlines the mechanisms behind these transitions to ensure systems meet human needs.