A framework for flight guidance along air streams

With the current performances of aeronautical communication, navigation and surveillance systems, free flight and traffic management through trajectory negotiation become a reality. However, the adoption of free flight in congested airspace leads to an increase of the number of potential traffic conflicts which are solved by diverting aircraft from their original flight plan, limiting the benefits of free flight. In this paper it is proposed to organize traffic in congested airspace along main air streams which are characterized by a flyable 3D track for modern transportation aircraft. Then aircraft position can be given in a local space indexed cylindrical coordinates system which should ease the management of traffic separation and surveillance. This should result in the need to develop new 3D space indexed guidance modes to perform lateral trajectory tracking while insuring time separation between successive aircraft.