New Concepts and Methods in Air Traffic Management

Collaborative Decision Making (CDM) embodies a new philosophy for managing air traffic [1]. The initial implementation of CDM within the US, has aimed at Ground Delay Program Enhancements. Work is currently underway to apply CDM technology and concepts in other areas including the distribution of NAS status information and the management of en-route traffic. In this paper, we analyze the initial implementation of CDM. After a description of the CDM history, we describe some of the tools that have been developed as part of the CDM effort. Furthermore future research and developments are traced.

Collaborative Decision Making (CDM) embodies a new philosophy for managing air traffic. The initial implementation of CDM in the US has been aimed at Ground Delay Program Enhancements (GDP-E). However, the underlying concepts of CDM have the potential for much broader applicability. This paper reviews on-going and proposed CDM research streams. The topic areas discussed include: ground delay program enhancements; collaborative routing; performance monitoring and analysis; collaborative resource allocation mechanisms; game theory models for analyzing CDM procedures and information exchange; collaborative information collection and distribution.

A growing number of major airports around the world are adopting demand management measures in response to increasing delays and congestion. These measures are mostly based on administrative allocation of slots through schedule co-ordination, a practice viewed by many as anti-competitive and running counter to efforts to de-regulate air transport markets. Congestion pricing can be either an alternative to administrative slot allocation or a complement to it. In this paper, we review briefly the theoretical principles of congestion pricing and discuss how recent advances based on queuing theory facilitate the resolution of some fundamental related technical issues. We then discuss practical difficulties in applying congestion pricing to airports and conclude that applications must necessarily deviate from theory by taking into consideration a number of institutional and practical constraints. We also ident the hard technical issues involved in applying dynamic congestion pricing schemes for demand management in en route airspace.

The need for a macroscopic air transportation modeling approach is discussed and a recently developed model is applied to the U.S. air transportation system. The new model is designed to estimate the maximum capacity of a national air transportation region. The model is based on empirically observed aircraft arrival rates, government published annual operational rate statistics, and analytically derived airport arrival/departure functions. The underlying premise is that the air transportation system can be modeled as a multi path, steady state network of queues, whose maximum capacity is the sum of the maximum airport operational rates, less airspace human factors limitations. Capacity is defined to be twice the hourly arrival rate (since departures equal arrivals in equilibrium). The validity of the model predictions is tested by: 1) observing reported airport delay values ranked in order of model estimated maximum capacity utilization; and 2) observing historical operational growth rates for airports that are now operating near predicted maximum capacity. A national capacity value is estimated and compared to observed historical and predicted growth rates. All planned runway additions are included in the national capacity estimate and a growing national capacity shortfall is predicted. It is estimated that the US is currently operating at 57% of maximum capacity and will be at 70% national capacity by 2010. It is observed that significant delays begin at about 50% capacity fraction and grow at a hyperbolic rate. The effect of adopting new technology and operational concepts is shown to have a better impact on capacity growth (i.e. up to 30%) than runway construction (i.e. 1% per runway). This work should be of interest to policy makers who are responsible for making investments in national and/or local air transportation systems and for those responsible for measuring the air transportation systems operational capacity.

This paper presents a methodology for the early phase of a systems engineering approach for future airspace system definition. A preliminary design process is proposed, supported by analysis methods and tools to generate performance trade data that decision makers can use for key investment decisions. The preliminary design process and toolset will allow broad trade studies across potential new operational concepts and enabling technologies, to ensure that significant improvements in aviation system performance can be achieved. The paper presents a framework for developing ATM operational concepts and a toolset architecture that will support performance analysis, spanning from technical subsytem performance, through human operators and traffic flow, to overall system performance indicators such as throughput, safety and affordability.

A shortfall in terminal capacity has become evident in the mature air transportation networks of the United States and Europe. ATM innovations can play a role in alleviating this capacity shortfall, especially at airports where new runways cannot be built because of space limitations or environmental constraints. Benefits are achieved by compressing the arrival stream to individual runways, ensuring efficient simultaneous use of multiple runways, ensuring proper traffic flow to the airport, and maintaining operations in the presence of unfavorable weather. This paper provides examples of initiatives in each of these areas.

A number of models and algorithms designed to optimize the management of the terminal area have been presented in the literature and/or have been implemented in some airport. Most of them focus their attention mainly on landing operations, while modeling capabilities concentrate on the runway complex, assumed to be a single runway in the simplest case, or, when necessary, examine specific configurations. In this paper, we propose a modeling approach to coordinate inbound and outbound traffic flows on all the prefixed routes, through a discretization of the whole space terminal area. Several operational constraints, like longitudinal and diagonal separations in particular regions of the airspace and different runway configurations (independent, parallel, crossing), can be represented in a uniform framework. In order to assess the model’s capabilities, we describe in detail a case study performed for the Rome Fiumicino airport for which we report also algorithmic results with respect to different performance indices.

The world community of aviation operations is engaged in a vast, system-wide evolution of procedures, technologies and services that significantly affect human/system integration. The nature of this evolution is relaxation of restrictions in air transport operations wherever feasible. The relaxation includes schedule control, route control, and, potentially, separation authority in some phases of flight, for example aircraft self-separation in enroute. The dynamic concept of operations provides new challenge to the human operators of that system. The human operators (pilots, air traffic controllers, and airline operations personnel) must monitor system performance as they do now, but also predict the impact of the distribution of authority and control that might result as a function of the airspace configuration, aircraft state or equipage, and other operational constraints [9, 10]. In order to safely and effectively define the new process and procedures for this evolving concept, the human operator’s performance must be clearly and consistently included in the design of the new operation and of any automation aiding that is proposed to help the operators in their distributed activities. The experiment reported here was undertaken to characterize the impact of a shift in separation authority on controller performance in a complex center operation. Controllers managed simulated air traffic in the OCALA sector of the Jacksonville Center. Controllers managed the traffic under conditions of full positive ground control under two operating conditions and two levels of separation authority being ceded to aircraft. Measurements were made across a range of operational and operator variables. Significant differences in both operational and subjective measures were found in response to the primary manipulation of control authority.

The increased ability to exchange information between Pilots, Controllers, Dispatchers, and other agents is a key component of advanced Air Traffic Management. The importance of shared information as well as current and evolving practices in information sharing are presented for a variety of interactions, Controller-Controller interactions, and Airline-ATM interactions.

The article presents a study conducted at EUROCONTROL which investigates the limited delegation of separation assurance to the pilot. Firstly, a problem analysis is proposed based upon a new dimension — the notion of “level of delegation”. Secondly, the principles of the concept are presented, and the main issues arising are discussed. Finally, the main results of the initial evaluation are presented. The overall feeling can be summarised by “promising with a great potential”: controller availability could be increased. In addition, the notion of “flexible use of delegation”, which enables the controller to select the appropriate task to be delegated to the pilot, would enable gradual growth of confidence in the method. This notion would also provide flexibility to use the method under different traffic conditions, airspace constraints, and controller’s practice level.

The Direct-To Tool helps controllers identibi all aircraft in their airspace that can reduce the time of flight en route by flying “direct-to” a waypoint on their flight plan located closer to the destination airport. The Tool provides controllers with a list of all aircraft eligible for a direct -to clearance, ordered by minutes saved. In addition to the call sign (ACID) of the eligible aircraft and the potential time saving, the list also includes the name of the waypoint for the direct -to clearance to be issued as to well as the conflict status of the direct- to trajectory. The trajectory analysis and conflict detection algorithm that generates the list of eligible direct-to aircraft uses the trajectory synthesis engine built into the CTAS software. The Direct-To trajectory is sent to the Center’s host computer via the CTAS-to-host data link, where it is registered as a flight plan amendment. After completing the amendment transaction, the controller would issue the Direct-To clearance to the pilot of the aircraft. Operation of the Tool in the Fort Worth Center is estimated to save more than 1000 minutes of flight time per day.

A lot of work and theory has been done and written on validation issues. The purpose of this paper is to provide information on the concrete experience in France, related to the validation of new concepts or new functionality of the ATM system in the last ten years. Moreover, it contains the experience results.

Improved safety and capacity in the terminal area are major aviation concerns. Weather is a major factor in accidents and delays within the US accounts for 33% of commercial carrier accidents, 27% of general aviation accidents and greater than 70% of the serious delays in the US aviation system. The current safety focus is on the detection and prediction of rapidly changing convective weather weather, icing, and clear air turbulence. Air traffic personnel are reluctant to take on major new responsibilities for the separation of aircraft from hazardous weather, so there are major initiatives underway to providing better information to airline pilots and operations center personnel via the Internet. We discuss how terminal delays due to convective activity and adverse winds have been dramatically reduced at several major U.S. airports through real time integration of various terminal area weather sensors. The extension of this sensor fusion approach to ceiling and visibility prediction and, reducing wake vortex separations on a weather adaptive basis is also reviewed.