Environmental Optimization of Aircraft Departures: Fuel Burn, Emissions, and Noise (2013)

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1 Environmental Optimization of Aircraft Departures: Fuel Burn, Emissions, and Noise As airport operations continue to expand as infrastructure is modified to meet the grow- ing demand for air travel, they need to balance their growth with environmental constraints. Although the main environmental concern continues to be noise, a more comprehensive approach needs to be implemented to better understand the effects of airport growth and changes. Indeed, the implementation of new aircraft and navigation technologies under the Next Generation Air Transportation System (NextGen) will require both noise and emis- sions, as well as fuel burn, to be assessed in order to fully understand the effects from such complex new technologies. Although the tradeoffs between noise, fuel burn, and emissions have been extensively ana- lyzed for Optimized Profile Descents (OPD), much less has been accomplished for noise abatement departure profiles (NADPs). As quieter airframe and engine technologies are developed, more direct flight tracks may be used with minimal (or no) effect on noise but noticeable reductions in fuel burn and emissions. To assess such cases requires methods to analyze a range of possibilities to identify optimum scenarios. Starting with approximately 100 documents, literature reviews were conducted to examine existing studies on tradeoffs dealing with noise, fuel burn, and emissions, especially those dealing with airport growth and capacity impacts. The reviews included data gap identifica- tion to address the following issues: • Different variations of NADPs; • Interrelationships between takeoff profiles and ground tracks; and • Airport throughput impacts on noise, fuel burn, and emissions. The literature reviews revealed that any study involving noise abatement tracks needs to consider the local community’s reactions to changes in noise versus other environmental impacts. Although an established noise abatement procedure cannot be significantly altered, it may be optimized to help ensure that maximum reductions in fuel burn and emissions are achieved for each scenario. Based on the literature reviews, protocols were developed for analyzing the tradeoffs between the environmental impacts (i.e., noise, fuel burn, and emissions) and airport capac- ity. The protocols were developed as follows: 1. Collect necessary airport data, 2. Develop ground tracks and profiles, and 3. Perform tradeoff analysis. The protocols were used to assess nine airports as part of a set of case study analyses. The selected airports constituted a good mixture of airport size, different types of NADPs, S U M M A R Y

2aircraft types, and population densities. The case studies showed that, in general, even rela- tively small changes in noise exposure can appreciably affect reducing fuel burn and emis- sions, although the benefits to runway throughput may be minor and, in some cases, neg- ligible (except for fanning). The effect on local population varied from airport to airport, and, in some cases, a small impact on community noise could be traded for larger reductions in emissions. On the basis of the data generated from such case studies, tradeoff curves can be developed between the various impacts (e.g., noise versus emissions). Depending on the location of noise-sensitive populations, the direct tracks may produce the most noise impacts while producing the most reductions in fuel burn and emissions. A spreadsheet-based, electronic tool was also developed—the Departure Optimization Investigation Tool (DOIT)—to enable users to better understand the tradeoffs among noise, fuel burn, and emissions when conducting optimization assessments focusing on manipu- lating airport fleet, operations, and the use of different departure tracks. Although airport capacity/throughput is not a directly adjustable option in the tool, the tool’s allowance for changes in operations and track utilization can be used to consider such effects. DOIT provides a hypothetical airport scenario that can be used to analyze various what-if cases involving different NADPs and allows for changes to the fleet mixes, track utilizations, and future technologies as represented through changes in aircraft source noise, fuel burn, and emissions characteristics. The output results are presented as reductions (or increases) in noise, fuel burn, and emissions, which can be used to identify optimum conditions for each modeled scenario.