Capacity, Entropy, and Safety: A Metric-Based Framework for Urban Airspace structure Evaluation

The rapid expansion of Urban Air Mobility (UAM) demands safe and efficient airspace designs capable of balancing capacity, safety, and reliability. This work introduces a set of lightweight, graph-based metrics: entropy, capacity, and safety. These indicators enable systematic evaluation of urban airspace structures without relying solely on extensive simulations. Syn- thetic layouts and real urban districts of Barcelona are analyzed to assess the behavior of these metrics under both controlled and realistic conditions. Results show that the capacity metric provides the most consistent predictor of network performance, while the entropy metric offers complementary insights into its reliability. Safety is quantified through contingency and confor- mance scenarios, revealing that contingency-related return-to- launch maneuvers consistently generate conflicts, whereas confor- mance deviations are largely mitigated under current operational assumptions. Overall, the proposed framework demonstrates that combining capacity with entropy yields robust assessments of UAM network designs, while safety analysis highlights the necessity of integrating contingency management strategies into airspace planning.