Performance of data link communications in surface management operations

The modernization of the nation´s air transportation system is necessary to accommodate forecasted traffic growth while ensuring safety. The National Airspace System (NAS) capacity is constrained by airport arrival and departure rate limitations due to factors such as weather delays, airline schedule conflicts, and aging infrastructures. New technologies such as data link messaging between ground-based air traffic management systems, tower controllers and flight decks, controller surface decision support tools, and cockpit digital maps are being developed to meet airport capacity upgrade needs. The benefits sought by data link are to reduce the need for voice communications between the pilot and controller, lower the likelihood of pilot readback and controller hearback errors, which, in turn, should reduce operator workload. The benefits sought by the surface management tools are to provide more optimized taxi routes, taxi conformance monitoring, and departure scheduling; which, in turn, will increase take-off capacity while reducing fuel, noise and environmental impacts. The data link messages are planned to cover all aspects of the taxi-out and taxi-in operations. However, for safety reasons, tactical process steps (e.g. runway crossing clearances) will still be issued verbally by the controllers. Data link messages are planned to eventually become the predominant mode of communication between controllers and pilots, but will still be supplemented by voice-based instructions as well as the use of paper-based airport maps. The transition to data link operations will impact how pilots and controllers communicate and share common and synchronous situation awareness (SA). The user interface design and operational procedure requirements to ensure that the desired safety and efficiency benefits still need definition. The paper provides a summary of past research activities and highlights unresolved research issues related to the implementation of data link taxi messagi ng within an integrated air-ground surface traffic management system.