Compilation of Noise Programs in Areas Outside DNL 65 (2009)

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27 This ACRP synthesis provides background on the regulatory, policy, and legal development of Day–Night Average Noise Level (DNL) 65 in the United States, as well as results of an online survey of 35 airports that have demonstrated interest in the issue of noise outside DNL 65. The responses to the survey on noise issues outside DNL 65 included the following: • A majority of respondents (83%) indicated that noise issues outside DNL 65 were “important,” “very impor- tant,” or “critical” to their airport. The remaining 17% reported that noise issues outside DNL 65 were “some- what important” or “not at all important.” • The most frequently cited method of minimizing noise outside DNL 65 was operator education and outreach (74% of respondents), followed by noise abatement flight tracks (69%), preferential runway use programs (66%), noise abatement departure or arrival procedures (60%), and ground noise control (51%). • “Community concerns” were indicated by 80% of respondents as the motivation for addressing noise out- side DNL 65; 57% also indicated that “preventive plan- ning” was a motivation. • Seventy-four percent of respondents indicated that more than three-quarters of their airport’s noise complaints came from people who live outside DNL 65. Survey responses also revealed the following: • A majority of airports use noise abatement departure (63%) and arrival (51%) flight tracks and departure (54%) and arrival (40%) cockpit procedures to minimize noise over residential and other noise-sensitive neigh- borhoods outside DNL 65. However, among surveyed airports there is no consistency in methodology for eval- uating the effectiveness of noise abatement outside DNL 65, and there is little guidance from the FAA on appro- priate metrics or criteria for evaluating noise abatement procedures. Responses to the survey indicated that in cer- tain areas airport staff is not privy to the cost incurred by airlines and the FAA of implementing various actions, as the responses noted that information is not available. Finally, respondents report that noise abatement flight tracks are somewhat more effective than noise abatement procedures at reducing noise complaints. • Most airports reported some procedures to minimize noise from ground operations such as taxi and pre-takeoff runups (69%); 25% of those airports reported that the procedures were developed primarily to address noise outside DNL 65, and an additional 38% reported that the procedures were developed to address noise issues both inside and outside DNL 65. The most common types of ground noise control include physical con- struction of blast fences (31%), ground runup enclo- sures (11%), and noise barriers/berms (20%); as well as runup procedures (29%), pre-takeoff runup policies (23%), reverse thrust policies (14%), and simply mov- ing the aircraft away from noise-sensitive communi- ties (23%). • More than half of the surveyed airports (57%) reported having land use compatibility measures that apply out- side DNL 65. The tools used by airports for land use compatibility planning include zoning, building permits that require sound insulation of residential and noise- sensitive nonresidential land uses, and disclosure to residents. Respondents reported a wide range of effec- tiveness: 21% said their efforts were “very effective” in preventing incompatible land uses outside DNL 65, 64% said their efforts were “somewhat or moderately effective,” and 16% said their efforts were “not effec- tive at all.” • The majority of respondents (58%) do not provide sound insulation to homeowners living outside DNL 65. How- ever, 20% provide sound insulation for homes in contigu- ous neighborhoods (“block rounding”), and an additional 15% provide sound insulation for homes within the DNL 60 dB contour. • Nearly three-quarters of respondents (74%) reported that they use both websites and face-to-face meetings to communicate with people exposed to noise outside DNL 65. Airports also use online flight tracking (40%), newsletters (40%), and a variety of other tools such as quarterly and annual noise reports, and noise staff driven outreach tools. • The responding airports communicate with pilots about noise outside DNL 65 in a number of ways: the most common are pilot briefings (40%) and Jeppesen inserts (40%), posters and handouts (37%), and FAA standards (17%); other methods include airfield signage, Airport Facility Directory Special Notices, videos distributed through flight schools, and phone calls. Two case studies demonstrate that there is a strong need for airports to have continued flexibility in addressing noise out- side DNL 65—whether because communities have demanded it (Naples Municipal Airport) or because the airport has CHAPTER EIGHT CONCLUSIONS

conducted proactive planning (Dallas/Ft. Worth International Airport). This synthesis identified the need for additional research in the following areas: • “Toolkit” of strategies to address noise outside DNL 65— This synthesis identified a range of strategies employed by airports to address noise outside DNL 65. A compre- hensive toolkit with recommended best practices could help airports identify those strategies best suited for a variety of noise issues outside DNL 65. • Communication—Better methods are needed for work- ing with local communities; some of this work is already underway through ACRP Project 02-05, Guidebook on Community Responses to Aircraft Noise. • Evaluation of noise abatement strategies outside DNL 65 including noise metrics, criteria, and benefit-cost analyses. 28 • Land use measures—This study identified a need to identify the barriers to implementing land use measures; some of this work is ongoing through ACRP Project 03-03, Enhancing Airport Land Use Compatibility. • Complaints—The relationship between noise com- plaints and noise level is still not well understood. Areas for research in this area include: (1) an evaluation of how complaints are made, recorded, and dealt with; (2) how airport operators use and evaluate complaint levels to drive noise programs; and (3) how airport operators evaluate the effectiveness of noise programs through changes in complaints. • Case studies—The case studies described in this synthe- sis are instructive; however, the scope of this project did not allow for an in-depth analysis or discussion of some of the best practice strategies that could be derived from these airports.