TagHMMH(8)

This 2021 FAA report analyzes the Neighborhood Environmental Survey (NES), a large-scale study examining how aircraft noise affects communities around 20 U.S. commercial airports. Researchers surveyed over 10,000 residents and found that annoyance with aircraft noise increases steadily as noise levels rise, with significantly more people reporting high annoyance than older studies had suggested. The findings provide an updated national curve showing the relationship between measured noise exposure (DNL) and community annoyance, which can inform airport noise policy decisions.

The FAA conducted a large-scale Neighborhood Environmental Survey (NES) of 10,000 people near 20 U.S. airports to measure how aircraft noise affects community annoyance, finding that significantly more people are bothered by noise than older studies suggested — about 66% of respondents were highly annoyed at 65 decibels (DNL) and 20% at 50 decibels. The agency uses the Day-Night Average Sound Level (DNL) metric to measure noise exposure and is reviewing whether its longstanding 65 DNL threshold for 'significant' noise impact should be updated. The FAA is seeking public comment on these research findings before making any changes to official noise policy.

This document presents findings from a Sea-Tac Airport Ground Noise Study, shared at the Highline Forum on November 20, 2019. It explains how aircraft ground noise travels and changes with distance, noting that sound levels drop by 6 dB every time the distance doubles and are further reduced by atmospheric absorption and soft ground surfaces. The study also covers how temperature gradients affect noise, with sound bending upward in normal conditions and downward during temperature inversions, potentially increasing noise impacts on nearby communities.

In October 2019, community advocate Sharyn Parker responded to a request for public input on a Sea-Tac Airport airfield ground noise study being conducted by consulting firm HMMH. Parker argued that the consultant should first analyze existing noise monitor station data, correlate it with engine run-up records and resident complaints, and review compliance with Washington State noise regulations (WAC 173-60) before seeking community feedback. She also raised concerns about non-functioning noise monitors, the airport's unverified claims about off-site engine testing, and potential overlap with a separate noise study tied to the airport's master planning process.

These emails, dated October–November 2019, relate to a study of ground-level noise at Seattle-Tacoma International Airport initiated by the StART Aviation Noise Working Group. Noise consultant Brad Nicholas of HMMH sought input from surrounding cities, including Burien (which had suspended its StART membership), on which noise sources to analyze and where to place monitoring equipment. Community advocate Sharyn Parker responded with detailed recommendations, arguing the consultant should first correlate existing noise complaints and monitor records with engine run-up events before soliciting public input, and identifying engine run-ups and reverse thrust as the two primary sources of airfield ground noise.

The 2018 FAA Reauthorization Act (H.R. 302) includes 14 provisions related to aircraft noise, several of which directly affect airports like Sea-Tac, including requirements for updated noise exposure maps, new community noise concern processes, and health impact studies. Key provisions call on the FAA to study alternative noise metrics to replace the current DNL standard, appoint regional ombudsmen to address noise complaints, and review how NextGen flight path changes have affected surrounding communities. Airports are advised to monitor FAA progress on these studies, as potential changes to the 65 dB DNL threshold and other noise compatibility guidelines could significantly impact community relations and environmental reviews.

This white paper analyzes the noise-related provisions of the FAA Reauthorization Act of 2018 (H.R. 302), which reauthorized the FAA through fiscal year 2023 and included 14 provisions directly or indirectly addressing aircraft noise. Key measures require the FAA to study alternative noise metrics to replace the Day-Night Average Sound Level (DNL) standard, update Noise Exposure Maps when operations change significantly, and consider dispersal headings for new flight procedures to reduce community noise impacts. Seattle is among the cities specifically identified for a health impacts study related to aviation noise, making these provisions particularly relevant to Sea-Tac Airport stakeholders.