FAQs

The Federal Aviation Administration (FAA) issued Title 14 Code of Federal Regulations (CFR) Part 150, Airport Noise Compatibility Planning, in January 1985. 14 CFR Part 150 provides airport operators with a formal process for addressing airport noise and noncompatible land uses. A “noncompatible land use” is a land use exposed to aircraft noise above the established Federal threshold for impacts. Part 150 Studies are voluntary; typically prepared by airports interested in improving land use compatibility with local communities. Part 150 Studies have two elements:

• Noise Exposure Map (NEM) Report – Shows existing and future aircraft sound exposure levels.
• Noise Compatibility Program (NCP) – Recommends measures to address aircraft noise. FAA-approved measures can be eligible for federal funding.

The Port is preparing a Part 150 Study to assess its current aircraft noise conditions. The Study provides a structured approach for airport operators, pilots, neighboring communities, and the FAA to evaluate opportunities to address community concerns regarding noise exposure while preserving safety and operational capabilities of the airport. The last Part 150 Study for SEA was completed in 2014. Since the last Study, changes in aircraft fleet mix and operational levels warrant an updated evaluation of the airport noise environment and evaluation of measures to address potential aircraft noise impacts. Measures approved by the FAA will be incorporated into SEA’s overall noise program.

The Port and Consultant Team began coordination for the Part 150 Study in early 2024. The Study is expected to take approximately three (3) years, with study completion and FAA approval of the NCP scheduled for 2027. This includes the time needed to gather data, conduct public outreach, and allow for FAA review. The Port and Consultant Team will take the time needed to create NEMs and an NCP that comply with 14 CFR Part 150.

This will be SEA’s fifth Part 150 Study. The Port completed the Airport’s original Study in 1985, with updated Studies completed in 1992, 2002, and most recently 2014.

The Part 150 Study Noise Exposure Map (NEM) Report will show existing (anticipated to be year 2025) and future (anticipated to be 2030) aircraft noise exposure levels. The Report will also explain how these levels were determined, including factors such as current and future projected aircraft operations, aircraft fleet mix, and runway utilization. The FAA will then review and accept the NEMs, provided they comply with Federal regulations. NEMs can provide the basis for potential eligibility for sound insulation programs and other initiatives.

After the NEMs are completed, the Noise Compatibility Program (NCP) process will begin. An NCP includes measures for addressing noncompatible land uses. Recommendations may include sound insulation, zoning, changes in aircraft operations, and other measures. The FAA must review and determine approval for each recommended measure in the NCP. Measures approved by the FAA may be eligible for federal funding.

The Port operates a Noise and Operations Monitoring System (NOMS) at SEA that consists of 24 permanently placed noise monitors. Portable noise monitoring may be conducted during the Part 150 Study to better understand noise levels in SEA’s surrounding communities. However, Federal regulation requires the use of a computer model to determine noise exposure in Part 150 studies. This allows calculation of noise exposure at numerous points around the airport. It also allows prediction of future exposure levels based on expected changes in aircraft activity.

The Aviation Environmental Design Tool (AEDT) is a software system designed to model aircraft performance to estimate noise exposure. It was developed by the FAA and released in 2015 to replace the Integrated Noise Model (INM), which was the model used for SEA’s previously completed Part 150 Studies. The FAA requires the use of AEDT to develop noise exposure contours for Part 150 Studies.

The AEDT uses aircraft flight tracks and profiles, aircraft fleet mix, runway configuration and use, terrain, and meteorological conditions for model inputs. With these inputs, AEDT produces noise exposure contours that are used for land use compatibility planning.

Day-Night Average Sound Level (DNL) is an average of sound levels that occur in a 24-hour period, expressed in decibels (dB). Sound events that happen between 10 P.M. and 7 A.M. receive an additional weight of 10 dB. The additional 10 dB weight means that every nighttime sound event is counted the same as 10 daytime events. This extra weighting represents the greater annoyance that nighttime sounds typically cause for most people.

When calculating aircraft sound exposure, the model uses the average number of operations in a 24-hour period based on one year of aircraft operations data. Then the sound levels for these operations are averaged, with the 10 dB weight for nighttime operations, to calculate DNL values. The FAA requires the DNL noise metric for Part 150 studies. DNL 65 is the federal threshold for land use compatibility.

The Port will receive input from the major stakeholders of the airport, which includes the FAA, local governments, pilots, air traffic controllers, and the general public. Throughout this Part 150 Study, public workshops will be held, and Study information will be shared during these workshops. A Technical Review Committee (TRC) has also been formed to provide technical input throughout the study process. The TRC is made up of members of various stakeholders including the near-airport communities. The public is encouraged to provide input throughout the Study process.

Airport Administration

The Port is the Sponsor of the Part 150 Study. The Port is responsible for identifying potential ways to reduce aircraft noise effects on near-airport communities. Providing sound insulation and flight path changes are examples of these measures, which must provide a noise benefit to noncompatible land uses. No measure can discriminate against aircraft operators, create an unsafe situation, hinder air navigation, or interfere with interstate commerce. The FAA must approve any changes in aircraft operations.

Federal Aviation Administration (FAA)

The FAA’s primary role is to ensure safe and efficient use of the National Airspace System. FAA Air Traffic Control (ATC) is responsible for aircraft movement on the airfield and in the air. Only the FAA has the authority to change aircraft operations. Any operational changes recommended by the Port must be consistent with operational safety and all legal requirements. The FAA must approve any recommendations resulting from a Part 150 Study.

Local Government

Local government provides near-airport land use planning, zoning, and housing requirements and can limit land uses around airports to those compatible with airport operations.

Pilots

Pilots are responsible for the safe operation of their aircraft. Although some airlines have procedures to reduce noise, and ATC assigns the flight path and altitude, pilots maintain final authority due to safety. In general, pilots decide whether to follow procedures that reduce noise.

Residents and Prospective Residents

Residents can provide input about noise concerns. Residents should also understand actions that can (and cannot) be taken to reduce aircraft noise effects. Potential future residents should familiarize themselves with noise and flight path information.

The Port and the Part 150 Study process encourages public and near-airport participation. There will be several public workshops during the Study process. The first public workshops will introduce the Study process. The Port will update the Study website with upcoming meeting information as the Study moves forward.

Please submit comments specific to the Study in person at the public workshops, by email to P150@portseattle.org, or by mail to:

Aviation Noise Programs
C/O SEA Part 150 Study
17801 International Blvd, #6012M
Seattle, WA 98158-12025

Please focus your comments on the Study content or process. Specific aircraft event complaints should be sent through the Noise Complaint Hotline at 206-787-5393 or online comment form, not to the Study Team. Further information regarding the Noise Programs Office and submitting noise concerns can be found here.

No. The FAA has sole jurisdiction over aircraft operations at SEA. Due to the Airport Noise and Capacity Act (ANCA) of 1990, public-use airports that receive FAA grant funding like SEA are federally mandated to remain open to all aircraft operators, and usage of the airport may not be restricted or limited.

The Port has sound insulated more than 9,400 single-family homes and 6 condominium complexes since 1985. In 2024, the Port initiated the Sound Insulation Repair and Replacement Pilot Program to evaluate the current condition of products that were previously installed as part of the ongoing Sound Insulation Program. The first phase of the pilot program includes a survey distributed to homeowners assessing the condition of previously installed sound insulation products. Based upon the survey findings, repair and replacement program criteria will be established to move forward in addressing issues with potentially defective products. The pilot program recommendations will be sent to the Port Commission for review of the proposed program for approval and implementation.

The SAMP is a separate study and is unrelated to the Part 150 Study. The SAMP recommends approximately 30 Near-Term Projects (NTP) that will support forecasted passenger and cargo demand, improve efficiency, safety, access to the Airport, and support facilities for airlines and the Airport. These projects are anticipated to be complete or under construction by 2032. The Port and FAA are conducting an environmental review of the SAMP NTPs.

Since the completion of the most recent Part 150 Study in 2014, the Airport has seen an increase in aircraft operations. In 2016, the number of annual operations at SEA topped 400,000 for the first time since 2001 and has remained roughly at that level since, other than during the COVID-19 pandemic.

The FAA approved several NCP measures to abate aircraft noise, control land development, mitigate the impact of noise on non-compatible land uses, and implement and update the program. Measures included both the continuation of previously approved measures as well as proposed new measures for further exploration.