LINK2000+ REAL-TIME SIMULATION
Introduction
Simulation Overview
Results – Benefits and Issues
Conclusion
Full report and
other links
The LINK2000+ Real-time Simulation was an experiment conducted at the EUROCONTROL Experimental Centre (EEC) to evaluate the operational impact of the LINK2000+ datalink services. The experiment, involving Italian and French airspace, evaluated controller working methods using various levels of traffic, different percentages of datalink equipage, and an advanced stripless controller interface with integrated datalink functionality.
Results indicate that a significant reduction in voice channel occupancy can be expected, but that to obtain a similar reduction in controller workload other factors must be considered such as the airspace environment and the datalink interface provided.
The provision of datalink did facilitate the transfer of tasks from the Tactical Controller to the Planning Controller and allowed the evaluation of new working methods with a view to balancing sector workload. However, some changes may influence the effectiveness of controller teamwork and situational awareness. The LINK2000+ experiment underlined the potential benefits, while identifying that further study is still required. The study also provided important indicators for system introduction and identified good practices and design principles for the wider implementation of datalink in Europe.
The project team conducted the experiment over a three-week period (January 21 to February 8, 2002), with the first week allocated to system training and the following two weeks to system evaluation.
In order to assess the operational impact of those datalink services selected for early implementation, the EEC developed a simulation facility that integrated the technical functions of datalink communication with a generic controller interface (EATCHIPIII). This simulation facility was used to explore the impact of introducing datalink functionality in the next five years.
The simulation sought to widen the previous operational evaluation by looking at a complete package of datalink services, combined with different levels of ground and aircraft datalink equipage, increasing traffic levels, and new working methods. The analysts also collected data regarding the ‘round trip’ message times, the setting of message time-outs, and the impact of these factors on controller activity.
The LINK2000+ Programme had a general objective to continue the evaluation of a set of air/ground datalink services that were considered globally interoperable, conceptually validated, and non-time critical, and therefore most likely to produce early ATM benefits. More detailed objectives investigated issues associated with mixed-fleet equipage, changing controller working methods and improvements to the datalink interface.
The experiment confirmed expectations that datalink has the potential to significantly reduce voice channel occupancy. Datalink also facilitated the transfer of tasks from the Tactical Controller to the Planning Controller. However, to benefit from an expected reduction in controller workload, an efficient datalink working method must be developed that fits within a system designed to handle both equipped and non-equipped aircraft.
The LINK2000+ simulation showed that this is feasible, with the controllers integrating datalink into a new beneficial working method. However, certain factors must be carefully considered if datalink implementation is to produce all the benefits desired.
The controllers reported that ACM (ATC Communication Service) produced substantial benefits for the Tactical Controller, including a large reduction in voice channel occupancy. These datalink instructions were not time or safety critical and could be transferred easily to the Planning Controller.
Controllers were more cautious regarding endorsement of ACL (ATC Clearance Service), used for sending control messages to the pilot. These messages could become time-critical and the transmission delay (implemented as 6 seconds) made sending datalink clearances unsuitable in highly tactical situations. The nature of the airspace was also an important factor, with airspace that provided longer anticipation of conflict situations, more suitable for this service.
With both controllers having control access to the aircraft, new issues of responsibility and situational awareness arose. Transferring clearance tasks to the Planning Controller may either involve implementing a new working method of shared responsibility, or could require the Tactical Controller to be responsible for actions made independently by the Planning Controller. Controllers may also need to share a single controlling strategy. Ultimately these issues will require further study.
The datalink interface proved to be a critical element in the datalink system provided. The interface needs to be clear and efficient, while seamlessly integrated with the system interface as a whole. National programmes will adopt their own design solutions, but the impact of these choices for successful implementation should not be underestimated.
The mixed environment, where roughly half of the aircraft were datalink equipped, proved the most difficult for the controllers to handle. At the end of the study, different methods of handling datalink and non-datalink aircraft had developed. In this environment, controllers regularly had to manage mixed-mode traffic in different scenarios. A transition strategy that addresses the different controlling methods for equipped and non-equipped aircraft will be essential to successfully navigate this phase of transition.
The LINK2000+ simulation conducted three weeks of exercises, successfully integrating the new LINK2000+ datalink services within a European traffic environment. Critical to the success of experiment was the involvement French and Italian controllers in the evaluation process. The programme not only benefited from controller input to design, but in achieving controller acceptance of the high-level datalink concept (albeit with some issues to resolve).
While it is important that EUROCONTROL continues to explore datalink implementation through research and development, these results indicate that the aim of a safer, more efficient, ATM system through datalink implementation is achievable.