Responsibility for European ATFM (Air Traffic Flow Management) has belonged to the CFMU (Central Flow Management Unit) of the Eurocontrol agency since 1996. Possible improvements in Europe’s existing ATFM procedures relate to two areas of optimisation: the increase in capacity of given airspace structures in order to minimise traffic regulations, and optimisation of traffic flow within given capacity constraints. Both the actual ATFM phases, one-year ahead to a few minutes before takeoff/area entry, and the ‘grey area’ between ATFM and active ATC (Air Traffic Control), sixty minutes to three minutes ahead of any situation, are objects of research relevant to these two areas of optimisation.
The overall objectives of the NOAA project were:
- to undertake research into flow management problems in order to develop optimised and integrated ATFM techniques;
- to consolidate this and other flow management research in order to recommend methods for optimising ATFM procedures, which will provide the basis for further enhancements to the unified European ATFM system.
The project has made recommendations for implementing improvements in the current philosophy for European flow management centred on CFMU. Recommendations refer to both the traditional scope of ATFM and the ATFM/ATC boundary, and include tools and strategies for:
- Enhancing the planning functions of the CFMU in several ATFM phases to make better use of existing capacity and optimise the traffic according to a pre-defined cost function.
- Improving the flexibility of traffic management processes during the pre-take off period. This would maximise the use of available capacity in rapidly changing and adverse operating conditions; in particular, the actions after slot allocation, but prior to sector entry, have been considered from various viewpoints, including multi-sector planning.
- Increasing the capacity of the given structures by more effective control techniques.
Recommendations that can be applied to existing European ATFM step-wise without major disruption include:
- formal documentation of flow management actions in ‘filter’ terms (a filter being a function, as accomplished by an algorithm, a system or a human agent, which acts on a problem space);
- automatic flow rerouting;
- situation data gathering and integration;
- metering of North Atlantic traffic by speed control advice transmitted via datalink.
Recommendations for longer-term changes include: controller-pilot datalinks, a multi-sector planning unit, cost function studies, and investigations in the area of tactical slot allocation.
The project results that relate directly to the traditional scope of ATFM are applicable to CFMU and its update programme. Research into the ATFM/ATC boundary has shown that work in this area could yield flow improvements. Any such work should be co-ordinated with the work of Eurocontrol's EATCHIP (European air traffic control harmonisation and integration programme) to be consistent with other lines of ATC developments. Several recommendations provided by the project envisage a higher level of control to improve flows. The implicit assumption of the project approach is that future improvement of traffic flows will be obtained by exercising at least as much control as today over flights, rather than by implementation of Free Flight concepts.