Extended Abstract for CRA DOT/FAA/TC-TN11/4

In today’s aviation system, air traffic controllers manage the separation between aircraft primarily using radar displays to visualize the aircraft positions and their trajectories. They are aided by basic automated decision support tools that predict potential future conflicts. When controllers determine an aircraft must be maneuvered, they advise the aircraft flight crew using two-way radio communications. To maintain today’s high level of safety with the anticipated growth in air traffic, the cost of separation management is expected to increase. Advanced automation is required to aid the air traffic controller and mitigate these costs. One such advanced separation management tool called Conflict Resolution Advisories (CRA) is being developed as a part of the Next Generation Air Transportation System (NextGen) initiative. CRA is a capability designed to aid the controller in formulating more efficient resolution maneuvers while ensuring safe separation of air traffic. CRA will provide a rank-ordered listing of potential conflict resolution maneuvers and is expected to improve operational efficiencies in terms of reduced maneuvering, increased use of fuel efficient maneuvers, more direct routing, and timelier controller actions. This paper summarizes the results of a fast-time simulation study that investigated the benefits and efficiencies of increased strategic implementations of conflict resolutions using CRA. The objective of the study is to support the cost benefit case for CRA by testing the hypothesis that earlier execution of resolution maneuvers will provide a benefit in regards to maneuvering time and flight fuel consumption. The Airspace Concept Evaluation System (ACES), developed by the National Aeronautics and Space Administration Ames Research Center (NASA/ARC), is a fast-time simulation tool used to simulate ground-to-ground air traffic. Within ACES, the Advanced Airspace Concept (AAC) package is used to simulate the separation management function by identifying, selecting, and applying conflict resolution maneuvers. Experimental design techniques were used to examine several factors including forecasted traffic demands from three years (2018, 2020, and 2025), three different airspace regions (east, central, and west), and an action time parameter. Action time is a parameter in AAC representing the maximum amount of time prior to loss-of-separation that a resolution maneuver can be implemented. This parameter was set at 5, 7, 9, and 11 minutes to reflect the change from the tactical approach currently used by controllers to the more strategic approach anticipated in the future. Additionally, two uncontrollable factors emerged during the study that significantly affected the responses; these factors are warning time and maneuver type. Four key metrics were used to estimate the benefits associated with the more strategic maneuvering. These were the percent difference of (1) fuel consumption, (2) flight distance, and (3) flight time of a treatment flight compared to its corresponding baseline flight without any maneuvers, and the (4) estimated maneuver delay time associated with each resolution maneuver modeled. Overall, the study predicted that fuel consumption will decrease as action time increases when the warning time is high but increase when the warning time is low. When considering maneuver type, a decrease in fuel consumption is observed for direct-to maneuvers while an increase is observed for vertical maneuvers, both as a function of action time. For both horizontal and speed maneuvers, the benefit is predicted to be marginal. However, the maneuver delay time decreases as a function of action time for all levels of warning time and maneuver types. Overall, more strategic controller actions result in a clear benefit for delay and fuel consumption for large warning times and direct-to maneuvers.