8.2.4. Implementation

8.2.4.1. Emerging Concepts

To attain the benefits of an improved ATM system, the United States and Europe have designed future ATM concepts as a logical progression of ICAO's work on CNS/ATM systems. The improvements described in Section 8.2.3 are expected to be implemented over the next 20 years. For a discussion of institutional and financial arrangements related to the implementation of CNS/ATM systems, see Chapter 10.

The U.S. effort, known as Free Flight, would enable optimum and dynamically determined flight paths for all airspace users through CNS/ATM technologies and the establishment of ATM procedures that maximize flexibility while ensuring positive separation of aircraft (RTCA, 1995). The European Organisation for Safety and Air Navigation (EUROCONTROL) has defined the future uniform European ATM System (EATMS) and an associated ATM Strategy for 2000+ as a system whereby flights will be managed from a total system perspective from gate to gate (EUROCONTROL, 1998b). This approach is expected to reduce fragmentation and improve efficiency considerably. The ATM 2000+ strategy and EATMS are taking environmental considerations into account, as a consequence of the environmental provision of the revised EUROCONTROL Convention (EUROCONTROL, 1997a).

Free Flight and the ATM Strategy for 2000+ were developed to accommodate the significant requirements of these two regions of the world within the context of ICAO concepts and policies. Remaining regions will be guided more specifically by ATM concepts being developed by ICAO. Harmonization of concepts under the CNS/ATM umbrella will lead, in theory, to an integrated global ATM system. CNS/ATM systems, along with efforts aimed at overcoming national limitations associated with sovereignty issues and funding of new systems, should result in a reduction in restrictions and a more optimized route system.

8.2.4.2. Regional Variations

There are a number of differences between air navigation infrastructure requirements in the various regions of the world. The United States and Europe embody the differences between two complex and highly developed regions. However, these two regions also share some similarities; increased capacity, for example, is the primary driver of implementation planning in both regions. On the other hand, developing regions are more concerned with improving safety, efficiency, and accessibility.

Integration and harmonization of various concepts and needs are required to achieve consistency in terms of safety and regularity and to attain the seamlessness required for efficient operation. Planning for implementation of improved air navigation systems based on CNS/ATM therefore cannot be accomplished in isolation. Regional air navigation plans, comprising listings of facilities and services required to serve civil aviation, are coordinated through the global mechanisms established by ICAO, and the ICAO standards and recommended practices provide a common framework for implementation and planning of systems. Regional bodies such as the African Civil Aviation Commission (AFCAC), the Arab Civil Aviation Commission (ACAC), EUROCONTROL, and the Latin American Civil Aviation Commission (LACAC) also provide common platforms for planning and implementation while ensuring commonality and coherency. Regions also establish bilateral relationships-such as between EUROCONTROL and the U.S. Federal Aviation Administration (FAA)-to address their unique and specific needs and to work more rapidly than traditional mechanisms allow.

8.2.5. Environmental Benefits Associated with CNS/ATM Implementation

8.2.5.1. Potential Environmental Benefits

Several studies associated with implementation of CNS/ATM systems have been carried out. Although some of these studies state their results in terms of cost/benefit and associated fuel savings and do not specifically address the environment, obvious correlations to reduced gaseous emissions (including NOx and carbon dioxide) can be drawn. Table 8-1 provides a summary of results from several case studies; this summary is taken from a paper presented by ICAO during the worldwide CNS/ATM systems implementation conference held in Rio de Janeiro in May 1998 (ICAO, 1998b). A preliminary EUROCONTROL study considered various ATM strategies and concepts that have the potential to reduce fuel burn. For two particular scenarios-free route airspace above 10,200 m and unconstrained "direct flight gate-to-gate"-potential savings of 1-2 and 7-8% were estimated, respectively (EUROCONTROL, 1997b). Table 8-2 presents the results of a preliminary assessment of potential fuel savings and resulting environmental benefits resulting from introduction of CNS/ATM in the national airspace system of the United States for the year 2015 (FAA, 1998b).

8.2.5.2. Rebound Effects

Introduction of capacity- and efficiency-enhancing measures such as those associated with CNS/ATM systems may attract additional air traffic. This phenomenon is referred to as the rebound effect. Introducing efficiencies hitherto not available to operators-efficiencies that result in lower fuel consumption and subsequently lower operating costs-may reduce fares and stimulate traffic and growth beyond that already anticipated based on the forecast demand for air travel. This eventuality cannot be overlooked because the net effect could be an increase in air traffic and consequently an increase in fuel burn and emissions. It is unclear to what extent any additional emissions caused by a rebound effect might offset anticipated reductions in emissions arising from CNS/ATM systems implementation. No studies providing evidence on the existence or size of the rebound effect have been carried out.

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