Findings and Recommendations
Given below is a complete list of the committee’s findings and recommendations, in the order in which they appear in the report.
Finding 1-1. Increasing Rate of Fuel Consumption. Fuel consumption is a key indicator for assessing trends in emissions. The aviation industry is growing and the use of aviation fuel is increasing at a rate comparable to that of other uses of fossil fuels.
Finding 1-2. Vigorous Action Required. Environmental concerns will increasingly limit the growth of air transportation in the 21st century unless vigorous action is taken to augment current research and technology related to the environmental impacts of aviation.
Finding 2-1. Growing Cost of Noise. The cost of aviation noise is significant and growing. Aviation noise reduces property values, contributes to delays in expanding airport facilities, and prompts operational restrictions on existing runways that increase congestion, leading to travel delays, high airline capital and operating costs, and high ticket prices.
Finding 2-2. Technology Accomplishments and Goals. Over the past 30 years, the number of people in the United States affected by noise (i.e., the number of people who experience a day-night average sound level of 55 dB) has been reduced by a factor of 15, and the number of people affected by noise per revenue-passenger-kilometer has been reduced by a factor of 100. New technology has contributed significantly to these improvements.
Recommendation 2-1. Balanced Allocation of Funds. Federal expenditures to reduce noise should be reallocated to shift some funds from local abatement, which provides near-term relief for affected communities, to research and technology that will ultimately reduce the total noise produced by aviation. Currently, much more funding is devoted to local abatement than to research and technology. Also, to avoid raising unrealistic expectations, the federal government should realign research goals with funding allocations either by relaxing the goals or, preferably, by reallocating some noise abatement funds to research and technology.
Finding 2-3. Achieving Noise Reduction Goals. Additional technological advances now possible could move most objectionable noise within airport boundaries. However, the goal is unlikely to be achieved by NASA’s target date of 2022, and achieving the goal may not fully alleviate the constraints that noise places on the aviation industry because of potential changes in the public’s perception of the importance of a low-noise environment to quality of life.
Finding 2-4. Major Impediments. The most significant impediments to reducing the impact of aviation noise (or emissions) include long-term growth in the demand for aviation services, long lead times for technology development and adoption, long lifetimes of aircraft in the fleet, high development and capital costs in aerospace, high residual value of the existing fleets, and low levels of research and development funding.
Recommendation 2-2. Technology Maturity and Scope. NASA and other agencies should sustain the most attractive noise reduction research to a technology readiness level high enough (i.e., technology readiness level 6, as defined by NASA) to reduce the technical risk and make it worthwhile for industry to complete development and deploy new technologies in commercial products, even if this occurs at the expense of stopping other research at lower technology readiness levels. NASA and the FAA, in collaboration with other
stakeholders (e.g., manufacturers, airlines, airport authorities, local governments, and nongovernmental organizations), should also support research to accomplish the following:
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Establish more clearly the connection between noise and capacity constraints.
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Develop clear metrics for assessing the effectiveness of NASA and FAA noise modeling efforts.
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Implement a strategic plan for improving noise models based upon the metrics.
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Harmonize U.S. noise-reduction research with similar European research.
Recommendation 2-3. Interagency Coordination. Interagency coordination on aircraft noise research should be enhanced by ensuring that the members of the Federal Interagency Committee for Aircraft Noise have budget authority within their own organizations to implement a coordinated strategy for reducing aviation noise.
Finding 3-1. Gap Between Technology and Demand. Continuation of ongoing technology research will reduce fuel consumption per revenue-passenger-kilometer by about 1 percent per year over the next 15 to 20 years. During the same time, the demand for air transportation services is expected to increase by 3 to 5 percent per year. An aggressive, broad-based technology program that encompasses propulsion systems, the airframe, and operational systems and procedures could significantly close this gap. Existing allocations of research funding and funding trends within NASA and the FAA do not support such a program.
Finding 3-2. Gap Between NASA Goals and Programs. NASA funding to achieve its goals for reducing CO2 and NOx emissions is insufficient to reach the specified milestones on time. Little or no funding is available for research related to other emissions, such as hydrocarbons, particulates, and aerosols, which may also have significant effects on the atmosphere locally, regionally, or globally.
Recommendation 3-1. Research on Global, Regional, and Local Emissions. NASA should continue to take the lead in supporting federal research to investigate the relationships among aircraft emissions (CO2, water vapor, NOx, SOx, aerosols, particulates, unburned hydrocarbons, and other hazardous air pollutants) in the stratosphere, troposphere, and near the ground, and the resulting changes in cirrus clouds, ozone, climate, and air quality (globally, regionally, and locally, as appropriate). Other agencies interested in aircraft or the environment should also support basic research related to these programmatic goals.
Recommendation 3-2. Eliminating Uncertainties. NASA should support additional research on the environmental effects of aviation to ensure that technology goals are appropriate and to validate that regulatory standards will effectively limit potential environmental and public health effects of aircraft emissions, while eliminating uncertainties that could lead to unnecessarily strict regulations.
Finding 4-1. Environmental Impact. The environmental impact of any industry, including aviation, would be reduced if equipment manufacturers, service providers, and consumers directly faced the full costs of their activities, including environmental costs. For air transportation, this would require industry, consumers, and others who benefit from a robust air transportation system to face the full costs of operations.
Recommendation 4-1. Considering All Costs and Benefits. To support the formulation of environmental goals and air transportation policies, government and industry should invest in comprehensive interdisciplinary studies that quantify the marginal costs of environmental protection policies, the full economic benefits of providing transportation services while reducing the costs (in terms of noise, emissions, and congestion), and the potential of financial incentives to encourage the development and use of equipment that goes beyond regulatory standards.
Finding 5-1. Status of Environmental Research. Research seeking to mitigate the environmental impacts of aviation is important to national and global well-being, but present efforts are operating with ambitious goals, unrealistic time-tables for meeting them, and few and diminishing resources.
Recommendation 5-1. Taking Advantage of Experience. The following lessons, learned since the advent of jet-powered aircraft, should be used to formulate and evaluate strategies for reducing the environmental effects of aviation:
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Success is not easy—it requires government support and federal leadership in research and development of new technology. Establishing a strong partnership involving federal, state, industry, and university programs is essential to progress.
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Changes in the impact of aviation on the environment occur on the scale of decades as fleets evolve; technological success in reducing adverse impacts occurs on the same or longer scales.
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The formulation of technological strategies to reduce the environmental impacts of aviation is hampered by significant uncertainties about (1) the long-term effects of aviation on the atmosphere, (2) economic factors associated with aircraft noise and emissions, and (3)
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the level of noise and emissions that ultimately will prove to be acceptable to airport communities and the general public, nationally and internationally.
Recommendation 5-2. Additional Research. To reduce conflicts between the growth of aviation and environmental stewardship, NASA, the FAA, and the EPA should augment existing research by developing specific programs aimed at the following topics:
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determining which substances identified by the EPA as hazardous air pollutants are contained in aircraft emissions and need to be further reduced
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understanding and predicting atmospheric response to aircraft emissions as a function of time on local, regional, and global scales
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exploring the suitability of alternate sources of energy for application to aviation, taking full account of safety and operational constraints
Recommendation 5-3. The Federal Responsibility. The U.S. government should carry out its responsibilities for mitigating the environmental effects of aircraft noise and emissions with a balanced approach that includes interagency cooperation and investing in research and technology development in close collaboration with the private sector and university researchers. Success requires commitment and leadership at the highest level as well as a national strategy and plan that does the following:
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coordinates agency research and technology goals, budgets, and expenditures with national environmental goals and international standards endorsed by the federal government
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periodically reassesses environmental goals and related research programs to ensure that they reflect current understandings of the impact of specific aircraft emissions on the environment and human health
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takes advantage of the unique expertise of both government and industry personnel and reverses the current trend of lessening industry involvement in NASA-sponsored environmental research and technology development
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reallocates funds in accordance with long-term goals, shifting some resources from short-term mitigation in localized areas to the development of engine, airframe, and operational/air traffic control technologies that will lead to aircraft that are quieter, operate more efficiently, and produce fewer harmful emissions per revenue-passenger-kilometer
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supports international assessments of the effects of aircraft emissions and the costs and benefits of various alternatives for limiting emissions
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expedites deployment of new technologies by maturing them to a high technology readiness level (i.e., technology readiness level 6, as defined by NASA) and providing incentives for manufacturers to include them in commercial products and for users to purchase those products