Today's air traffic management is organised in a fragmented way. Every time a plane enters the airspace of a Member State, it is serviced by a different service provider with different rules and operational requirements. This fragmentation impacts safety, limits capacity and adds to cost. Moreover, it slows down the decision making process necessary to introduce new technology and to tailor services to customer needs.

Like any other industry, air traffic control therefore needs to be more functionally on a regional basis. Airspace is to be organised following operational requirements regardless of national boundaries in 'functional airspace blocks'. Under the Single European Sky legislation, Member States are legally obligated to enter into such regional forms of integrated management.

Greater portions of airspace need to be operated as one single operational entity. Functional airspace blocks are the tool to reduce airspace fragmentation so as to enhance current safety standards and overall efficiency, to optimize the steadily growing capacity requirements of all airspace users and to minimise delays by managing the traffic more dynamically. These objectives can only be achieved through an increase of the scale of operations, regardless of national borders.

Functional airspace blocks are the toolbox with institutional, operational, technical, economic and social instruments to tackle fragmentation of airspace at its roots to meet users' expectations. So will implementing rules increase the interoperability of equipement.

This implies that the definition of functional airspace blocks involves a collaborative decision making exercise where all stakeholders have a role to play. While Member States have to provide the continuous political backing, the bulk of the technical work will need to be performed by the service providers.
Finally, airspace users will influence the process so that the outcome will be best tailored to the needs of the aviation community.

Functional airspace blocks are the toolbox with institutional, operational, technical, economic and social instruments to tackle fragmentation of airspace at its roots to meet users' expectations. Implementing the rules will likewise increase the interoperability of equipment.

Member States will have to ensure that these functional blocks shall: a) be supported by a safety case; (b) enable optimum use of airspace, taking into account air traffic flows; (c) be justified by their value added, including optimal use of technical and human resources, on the basis of cost benefit analysis; (d) ensure a fluent and flexible transfer of responsibility for air traffic control between air traffic units, (e) ensure compatibility between configuration of upper and lower airspace.
Airspace users, both civil and military, are appropriately involved and consulted in a continuous process, so that their needs are at the core of initiatives.
Service providers conceive of functional airspace blocks that fulfil the legal requirements on safety, functionality and added value.
With regard to territorial coverage, air navigation service providers have started exploratory discussions on the feasibility of functional airspace blocks in most of the Member States.

At present, there are nine FAB initiatives that have been notified to the European Commission: