یک فرایند تحلیل سلسله مراتبی از مدیریت ترافیک هوایی با پنجره های هدف

The main operational concept of Single European Sky ATM Research Programme is the notion of business trajectory. One possible implementation is based on the notion of a contract of objectives; an agreement among the main air traffic management actors on spatial and temporal intervals called target windows. These 4D windows are defined prior to flight departure by the airlines, airports and air navigation service providers to increase punctuality. We use an analytic hierarchy process to assess the opportunity of implementing this concept by considering the views of experts. The findings indicate that there are net benefits for airlines and air navigation service providers but not for airports

The Single European Sky ATM Research Programme (SESAR) aims at modernizing air traffic management (ATM) infrastructure by identifying the technological steps and priorities for implementing a new target concept (SESAR Consortium, 2007a). This concept is centered around the notion of business trajectories that consider airspace users’ intention with respect to any given flight. The ATM services are organized to guarantee that this trajectory is carried out safely and cost efficiently within infrastructure and environmental constraints. Business trajectories are expressed in four dimensions (latitude, longitude, flight-level and time) and evolve out of a collaborative decision making (CDM) process developed in two phases: flight planning and execution. The former starts several months before the day of operation: the flight is defined according to the airline schedule and specific resources are assigned to it (aircraft type, crew, network resources, etc.). On the day of the operation, the flight is made as closely as possible to the plan and deviations are managed to minimize their impact on the larger schedule. One mechanism to formalize the business trajectory is through contracts of objectives (CoO), as developed by the Contract-based Air Transportation System (CATS) research project (www.cats-fp6.aero). The CoO is a formal commitment among airlines, airports and air navigation service providers (ANSP) for the completion of each flight. It consists of a sequence of spatial and temporal constraints that constitute milestones to be met during a flight’s execution. These 4D intervals are the target windows (TW). They are defined at each area where responsibility between actors is transferred (e.g., between different area control centers). The determination of the TW in each CoO is by negotiations that take into account constraints such as runway capacities and en route congestion. Any divergence in the flight from the planned CoO, for example due to unforeseen weather conditions, triggers a re-negotiation. Under the current system, flight plans filed by airspace users constitute an intention to fly and there is no formal commitment to adhere to these. Moreover the various actors interacting during the execution of a flight are not fully aware of their differing objectives and priorities, and this can lead to a sub-optimal management of operations (Eurocontrol Experimental Centre, 2005). The CoO provides a formal description of each ATM actor’s objectives and requirements, as well as a mutual commitment to respect them, thus leading to improvements in planning and earlier detection of unplanned disruptions. This paper looks at the opportunity for implementing the CoO/TW concept, and weighs the benefits and drawbacks with respect to the current system. The assessment is made with the support of a group of experts from the CATS consortium. Subject matter experts belong to air traffic stakeholders: Air France Consulting (airline view), ENAV, the Italian Air Navigation Service Provider (ANSP view), and Flughafen Zürich AG, the company managing the Zurich airport (airport view). They are fully aware of the details of the CoO/TW concept having all been involved in the CATS project from the beginning. The assessment uses an analytic hierarchy process (AHP) methodology, which allows incorporation of qualitative and quantitative considerations (Saaty, 1977 and Saaty, 2000).

This paper analyzes the potential benefits and limitations of implementing a specific CDM process among airlines, airports and ANSPs in the framework of the European ATM system. The target of the proposed concept is to identify a set of 4D intervals (latitude, longitude, flight-level and time) called target windows which are defined at specific transfer of responsibility areas. These intervals are to be met by each flight during its execution to guarantee punctuality at destination. Target Windows are agreed prior to flight departure by means of a negotiation mechanism among all actors. They constitute the so-called Contract of Objectives for the flight. For three main stakeholders, we present two distinct Analytic Hierarchy Process models to evaluate the effect of the introduction of these agreed target windows in the planning and execution phases of a flight. A group of experts from Air France Consulting, ENAV SpA and Flughafen Zürich AG validated the layout of the six hierarchies and assigned priority values among the various criteria and alternatives. Our analysis shows that the implementation of the new protocol appears to be the preferable choice for the airline and the ANSP. The opposite holds for the airport. This result is quite robust in the first two cases. In the third, a clear inversion of attractiveness exists with optimization in the use of resources becoming less relevant. However, the economic situation from 2007 has forced the airline and the airport to limit investment. Some experts explicitly underlined that the same comparison made some time ago, and possibly some time in the future, would give an opposite result. For the ANSP, instead, the practice of full cost recovery allows to favor the increase of benefits. The lower performance of CoO/TW in the airport case may also depend on the fact that at the airport of Zurich some CDM mechanisms among airlines and the airport authority have already been established.