Miles-in-Trail Restrictions and Aviation System Performance: Chicago O’Hare Case Study

Miles-in-Trail (MIT) is the most common Traffic Management Initiatives (TMI). An MIT places a minimum spacing requirement between aircrafts at a specific location to manage the imbalance between capacity and demand at a given airport, or to support merging streams in the sectors. This paper focuses on the improvement opportunities from reduction of MIT. We design a model including estimation of planned arrival time and a deterministic model to assess the impacts of a given MIT or a set of MITs. Our model is applied to ORD airport of 2018 as a case study. As results show, if all ORD-sourced MITs were eliminated, the overall queueing delay would increase by 3.3 hours per day on average while arrival delay would decrease by 14.7 hours per day. We also found that ORD during 8:00-9:00, 11:00-12:00 and 17:30-18:30 tends to experience more throughput reduction when implementing MITs and those delayed flights are allocated into 9:00-10:00, 12:00-13:00 and 18:30-19:30 respectively. Our results strongly suggest that ORD-sourced MITs, while relieving some build-up of flights in the ORD terminal area, do so at a substantial penalty in the form of increased arrival delay and throughput shortfalls.