Flexible tube-based network control

One of the most restrictive aspects in today's Air Traffic Management (ATM) system is that aircraft are still largely limited to flying routes defined by fixed, ground-based navaids. With current air travel experiencing increasing amount of delay, it is evident that this inflexible jet route system will not be able to handle future demand, especially when jet routes get closed by hazardous weather constraints. However, not having any route structure in the NAS might not be a viable approach either as it could lead to high complexity and low traffic pattern predictability. For use in the Next Generation ATM system (NextGen), the Network Flow Organizer (NFO) has been designed as a Traffic Management Initiative (TMI) to control the topology of the air traffic flow network and its flow properties. The NFO alleviates en route congestion by creating airspace capacity through dense, automatically monitored traffic flows. This is in contrast to other TMIs that restrict capacity, such as Airspace Flow Program, miles-in-trail, ground delays and ground stops. The NFO forms and dissolves flows based on demand and the necessity to resolve demand-capacity imbalances, thus providing structure only when needed without unnecessarily constraining traffic. Such flows allow parallel lanes of traffic, creating high traffic throughput with low complexity and workload. The flows are dynamically relocated throughout the day to be safe from weather hazards and to avoid Special Use Airspace. A concept for protected slot templates is established to allow conflict free intersection of flows and turning at intersections.