1. Terminal Airspace Traffic Complexity Fedja Netjasov University of Belgrade Faculty of Traffic and Transport Engineering Division of Airports and Air Traffic Safety.

2. Why Terminal Airspace? Terminal airspace (TMA) represents transitional airspace between airports and ATC sectors; The TMA contains a high concentration of arrival trajectories converging on the airport as well as departure trajectories diverging from the airport.

3. Why Complexity? Mix of aircraft types resulting in different separation rules; Aircraft traverse the TMA at a broad range of speeds.

4. Definition of Complexity complexity presents a measure of quantity as well as quality of the interactions between the aircraft which are to be controlled (managed) by one air traffic controller.

5. Concept of Complexity airline costs airport and sector traffic complexity traffic situation noise level and air pollution influence on quality of passengers service controller workload

6. Basic assumptions Complexity depends on two groups of factors: static factors: TMA geometry; dynamic factors: traffic demand characteristics, distribution of traffic in TMA, etc.

7. Causes of Complexity (1) In the case of arrival, traffic complexity could be generated because of: existence of traffic on trajectories (C’ ARR ); potential catching-up situations (C’’ ARR ); potential conflict at trajectory merging points (C’’’ ARR ) ; demand exceeding trajectory capacity (C’’’’ ARR )

8. T s 1 3 4 2 T s 1 3 4 2 1 3 4 2 1 3 4 2 T r T r Catching-up situation Conflict at trajectory merging point

9. Causes of Complexity (2) In the case of departure, traffic complexity could be generated because of: existence of traffic on trajectories (C’ DEP ); potential catching-up situations (C’’ DEP );

10. Index of Complexity The concept of measuring complexity is based on a no-dimensional variable named “Index of complexity”. It is assumed that the Index of traffic complexity (C) consists of two components: Index of static complexity (C s ) and Index of dynamic complexity (C d ).

11. Index of Static Complexity - C s Depends on airspace geometry, i.e. number of trajectories and their length, number of runways, number of entry and exit points, etc.

12. Index of Dynamic Complexity - C d Presents the sum of two elements: Index of dinamic complexity in case of arrival traffic - C d ARR and Index of dinamic complexity in case of departure traffic - C d DEP

13. Index of Dynamic Complexity in case of arrival traffic - C d ARR Presents the sum of four elements: C d ARR = C ARR ’ + C ARR ’’ + C ARR ’’’ + C ARR ’’’’ C’C’’C’’’C’’’’

14. Index of Dynamic Complexity in case of departure traffic - C d DEP Presents the sum of two elements: C d DEP = C DEP ’ + C DEP ’’ C’C’’

15. Index of Complexity (rèsumè)

16. Experiments (1) Characteristics: TMA contains two arrival and two departure trajectories (generic case); hypothetical traffic; simulation of traffic in TMA

17. Experiments (2) Changes in the number of trajectories in the TMA - the purpose of which is to determine what influence changes in the number of trajectories have on the value of the Index of complexity; and Changes of traffic volume - the purpose of which is to determine what influence change in traffic volume has on the value of the Index of complexity.

18. Changes in the number of trajectories in the TMA (1) 2 3 4 24 op/h

19. Changes in the number of trajectories in the TMA (2) ≈ 800≈ 2100≈ 3200

20. Changes of traffic volume (1) 18 24 30

21. Changes of traffic volume (2) ≈ 130≈ 700≈ 2400

22. The main result of this research is the development of a model for the Index of complexity, of general use. This model could be used: for evaluation of current and novel organisational solutions for the TMA containing one single runway airport, or for estimation of effects of implementing new arrival and departure trajectories, on traffic in a TMA. Conclusion

23. Consideration of irregular situations such as missed-approaches; Consideration of influences of the meteorological situation on traffic; Analysis of traffic complexity for airports with multiple runways; Usage of weight factors; Consideration of heterogeneous aircraft fleet, etc. Further research

24. University of Belgrade Faculty of Transport and Traffic Engineering Department of Air Transport Division of Airports and Air Traffic Safety http://apatc.sf.bg.ac.yu Vojvode Stepe 305, 11000 Belgrade Serbia and Montenegro tel: +381 11 3091 352 fax: + 381 11 466 294 Thank you for your attention