Air and Ground Simulation of Terminal-area Fms Arrivals with Airborne Spacing and Merging

A combined air and ground simulation of terminal-area arrival operations was conducted at NASA Ames Research Center to evaluate Distributed Air Ground Traffic Management (DAG-TM) project Concept Element 11 (CE 11): Terminal Arrival: SelfSpacing for Merging and In-trail Separation. The simulation was the final DAG-TM study conducted at NASA Ames with funding from the NASA Airspace Systems Program Advanced Air Transportation Technologies (AATT) project. The study evaluated the feasibility and potential benefits of using pilot and controller decision support tools (DSTs) to support time-based airborne spacing and merging in terminal radar approach control (TRACON) airspace. Sixteen simulation trials were conducted in each treatment combination of a 2x2 repeated measures design. In trials ‘with ground tools,’ air traffic controller participants managed traffic using sequencing and spacing DSTs. In trials ‘with air tools’ seventy-five percent of aircraft assigned to the primary landing runway were equipped for airborne spacing and merging, including flight simulators equipped with an enhanced cockpit display of traffic information (CDTI) flown by commercial pilots. In all trials controllers were responsible for separation and issued clearances by voice. All aircraft were equipped with Flight Management Systems (FMSs) and ADS-B and entered TRACON airspace on charted FMS routes. Routes to the primary landing runway merged. Each scenario began with a traffic flow that was well coordinated for merging and spacing and ended with an uncoordinated flow. This paper presents the simulation and results of from an air traffic management (ATM) perspective. The results indicate that airborne spacing improves spacing accuracy and is feasible for FMS operations and mixed spacing equipage. Airborne spacing capabilities and the degree of flow coordination affect clearance selection. Controllers and pilots can manage spacing clearances that contain two callsigns without difficulty. For best effect, both DSTs and spacing guidance should exhibit consistently predictable performance.