Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
in 1987 to $9.5 billion in 1994. Except for the cost of fuel, environmental costs were not considered (U.S. Federal Aviation Administration, 1995). The European
Organisation for Safety and Navigation (EUROCONTROL) reports that air traffic delays in Europe are primarily the result of national institutional factors, capacity
overloads, and air traffic control inefficiencies. Association of European Airlines (AEA) data show that in 1989, the number of departures for short- and medium-term
flights delayed by more than 15 minutes was 23.8%. This figure dropped to 12.7% in 1993, but has risen steadily since then: The rate was 19.5% in 1997 and 20.1%
for the January-June 1998 period (Association of European Airlines, 1998). These data are consistent with EUROCONTROL data for the same years
(EUROCONTROL, 1998).
ICAO air traffic system policies, plans, standards, and recommended practices have not been regarded as measures that might be used to achieve environmental
gains. Studies assessing the costs and benefits of CNS/ATM modernization conclude that the benefits to airlines and passengers from reduced delays and fuel
savings far outweigh the incremental costs. Recent studies have focused on estimating the environmental benefits of a more efficient air traffic system. These studies
indicate that emissions from aviation may be reduced significantly. Although states are working within ICAO toward global modernization of the air traffic system, this
activity has only recently been placed in the context of addressing environmental issues (EISG, 1995; Aylesworth, 1997; U.S. Federal Aviation Administration, 1998a,
b).
Studies and working papers prepared for CAEP/3 Working Group 3 (emissions) and the ICAO Worldwide CNS/ATM Systems Implementation Conference (see
Chapter 8) indicate that improvements to the air traffic system could reduce annual fuel consumption 6-12%. For the total flight regime, 94% of fuel saving would occur
at cruise altitude and 6% below 900 m. NO x reductions are estimated to be 10-16%. This discussion of measures for mitigation leads to the following conclusions:
. Potential gains from operational measures within the current air traffic system are much smaller than those that may be gained through modernization of the
air traffic system.
. Although modernizing the air traffic system and improved operational measures are important environmental policy instruments in their own right, delayed or
early realization of their potential would have adverse or beneficial environmental consequences, respectively.
These conclusions have important environmental policy implications. Successful implementation of CNS/ATM is a daunting task that requires worldwide and regional
collaboration and cooperation. Impediments to be overcome include restricted airspace, sovereignty issues, institutional development, and finance, particularly for
developing nations and countries in transition.
10.4.2.2. Engine Emissions Stringency
ICAO Annex 16 emission standards are certification requirements for individual engines (ICAO,
1993b). Because of extensive regulation of the industry to maintain high levels of safety and to
maintain and promote competition, as well as comparatively long technology development and
product economic lifetimes (Chapter 7), ICAO has set limitations on emissions at their sources
(stringency) on the basis of the best achievable technology by all manufacturers.
These ICAO standards define emissions levels for unburned HC, CO, NOx , and smoke. They do
not address aircraft emissions of CO2 , sulfur dioxide (SO2 ), or H2O. Neither are there any ICAO
standards for trace compounds such as particulates, aerosols, certain types of HC, and other
nitrogen compounds. Aviation is not a source of nitrous oxide (N2O), a greenhouse gas. ICAO
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