Many airports recommend that aircraft operators use noise abatement departure procedures (NADP) to reduce the impact of noise on their neighboring communities. While minimizing noise impacts, these procedures may result in other adverse environmental and operational effects, including increased fuel burn, increased emissions, and reduced airport capacity. With the potential for near-term introduction of significantly quieter aircraft, research is needed on how to optimize or potentially eliminate NADPs without generating adverse noise impacts. In addition, a change from NADPs to more direct routing can increase capacity at the airports through more efficient use of facilities and airspace. Changing to more direct routing has the potential to decrease aircraft fuel consumption; and, given an increasing focus on climate change, decreasing fuel consumption can be important.
Efforts to reduce fuel consumption can broadly fit in two categories: aircraft/engine design improvements and air traffic optimization. With respect to optimization of air traffic, effort to date has primarily focused on the enroute flight phase. In contrast, research is needed that focuses on departure procedures that affect airports and airport communities more directly. For air traffic optimization, the focus of FAA’s “Next Generation Air Transportation System” (NextGen) has been on reducing flight time. Reduced flight times generally translate into aircraft engines burning less fuel and emitting fewer pollutants; however, for short-haul flights, fuel consumed enroute can be less than 50% of the total fuel burn. Arrivals and departures have received less attention despite the possibility that changes might achieve fuel savings during take-off and climb to cruise. One example of possible improvement to landing applications now receiving considerable attention is continuous descent arrivals (CDA). FAA has worked with airports, airlines, and academia to study the impact of implementing CDAs, which can simultaneously result in a reduction in fuel burn, emissions, and noise.
As quieter aircraft are introduced into service, an opportunity may arise to optimize departures and achieve a balance between noise and emissions impacts. In response to apparently limited efforts to date on environmental optimization of aircraft departures, research is needed to provide a tool to help regulators and airport managers make environmentally optimal decisions.
The objective of this research is to develop a departure optimization methodology to (1) quantify potential reductions in fuel burn and source emissions, (2) estimate possible increases in air traffic capacity that can be achieved by optimizing departure procedures while continuing to address noise exposure for communities around airports, and (3) account for existing and future fleet mixes and improvements envisioned under NextGen. In the context of current noise abatement departure procedures, this methodology should estimate environmental and capacity-related benefits associated with the following localized contributors: (a) source noise reduction in future engine/airframe technologies, and (b) realistic alterations to present noise abatement departure procedures to help regulators and airport management make environmentally optimal decisions. Although novel approaches to compare the impacts of climate change, degraded air quality, and community noise are welcome, the output of this research should, at a minimum, provide directly quantifiable metrics.
Status: The report has been completed and published as ACRP Report 86 in May, 2013.