From Perfect to Possible: Two Trajectory Based Operation Concepts for Future Terminal Manoeuvring Areas Workshop on ATM/CNS 2017 (EIWAC 2017)

In the last two decades, the approaches to improve the Air Traffic Management (ATM) system changes from a technology-push to a technology-pull principle, like the following ICAO Global Air Traffic Management Operational Concept citation shows. “…it was later recognized that technology was not an end in itself and that a comprehensive concept of an integrated and global ATM system, based on clearly established operational requirements, was needed.” This sentence from the foreword of ICAO Document 9854 (AN/458) defines the new way and determines the independence between technology and operating concept as the following quote emphases as well. „A key point to note is that the operational concept, to the greatest extent possible, is independent of technology; that is, it recognizes that within a planning horizon of more than twenty years, much of the technology that exists or is in development today may change or cease to exist.” To implement this approach, the document identifies significant changes as the ATM system migrates towards the concept vision. One such change is the introduction of Trajectory Based Operations (TBO) with an adapted operational concept and at least new technologies as an enabler. To choose supporting technologies, the different flight phases and boundary conditions have to be taken into account for a structured approach. Critical flight segments for a new concept are the arrival and departure phases and hence, the implementation of the concept in the vicinity of airports. In the TMA, especially at hub airports, the airspace is limited and the boundary conditions for arrivals and departures are high. For example, this includes the space for a transition structure considering different kinds of aircraft with different abilities based on different equipage up to airport specific noise abatement procedures. To avoid to lose oneself during the design of a new TMA airspace and procedures for TBO in all these constraints and to stay as close as possible with a “perfect” concept, only a few constraints were taken into account in the design. Core principle of the low limits design approach is that the routes between airports or merging points for the finals are all great cycle arc routes connecting the airports to minimize the flown distances. Hence, only nearly direct arrival and departure routes appear. The TMA itself is designed as small as reasonable to avoid additional flight distances in any kind of path stretching areas. Secondly, continuous descents operations should be possible. The questions on how the traffic can be guided by controllers and which tools they need were not addressed. In the paper such a design, including an evaluation with logged real traffic flows is presented and the requirements concerning a time-based guidance of the aircrafts are shown. Away from “make a dream come true” and facing the real world, in the second design, shown in the paper, the perfect low limits design is “ruined” to be able to deal with more constraints found in the near future in the air traffic management. The process of “ruining” the low limits design is done in way to minimize the required changes to take necessary constraints into account. In this near future design, the TMA provides a transition to deal with higher target time uncertainties, takes different aircraft equipage into account, and considers restricted areas. Furthermore, tools and HMIs were developed which are necessary to guide the aircraft through such an airspace design by the controller. Especially, this airspace design is able to deal with a mixed traffic situation, allowing better equipped aircraft to fly continuous descent profiles on negotiated trajectories while lower equipped aircraft have to conduct conventional approaches. The concepts were evaluated in different projects with varying traffic scenarios running in automated fast-time and real-time as well as human-in-the-loop simulations