Ted Stevens International Airport

Part 150 Noise Compatibility Study Update

Noise and Land Use Compatibility Study

Latest Happenings

See the Project Resources section for the slides and notes from the May Study Advisory Committee meeting, and check out the newly-added project timeline and expanded FAQ list below. Stay tuned for more information on this and other activities this summer.

Purpose

The Ted Stevens Anchorage International Airport (ANC) is conducting a Part 150 Airport Noise Compatibility Study to assess aircraft noise and land use compatibility in the surrounding areas. The goal of the project is for ANC, in consultation with partners and stakeholders, to develop recommendations to minimize and/or mitigate aircraft noise effects on surrounding communities and land uses. The ANC Part 150 Study was completed in 2015. This project is launching in 2025 with estimated completion in 2027.

There are two main parts of a Part 150 Study. First, modeling the noise through the update of the Noise Exposure Maps (NEMs) based on current and forecast future conditions. Second, to find reasonable solutions to the problems associated with noise generated by aircraft and present those solutions through an update of the Noise Compatibility Plan (NCP). The goal of the overall program is for ANC, in consultation with stakeholders, to develop a balanced program to minimize and/or mitigate aircraft noise effects on surrounding communities and land uses.

Timeline

A simplified version of the project timeline is below. To view a more detailed printable PDF that shows anticipated timing for Study Advisory Committee (SAC) Meetings, Public Workshops, and Public Hearing, click here.

Winter 2025

Launch
Begin project, refine study process; create Study Advisory Committee; create website

Spring-Summer 2025

Learn
Document conditions, prepare stakeholder engagement program, update aviation forecasts, conduct summer noise measurements

SAC Meeting (May)

Public Workshop (May)

Fall 2025

Analyze
Synthesize noise data, forecast noise exposure

SAC Meeting (Fall)

Winter-Spring 2026

Consider
Brainstorm preliminary alternatives to address noncompatible land uses

SAC Meeting (Winter)

Public Workshop (Winter)

Summer-Fall 2026

Recommend
Identify potential recommendations for operational, land use and programmatic measures

SAC Meeting (Summer and Fall)

Public Workshop (Fall)

Winter 2027

Summarize
Prepare recommendations and final report; submit to Federal Aviation Administration (FAA)

SAC Meeting (Winter)

Public Workshop (Winter)

Public Hearing (Winter)

Frequently Asked Questions

Part 150 of the Code of Federal  Regulations (CFR) formerly known as FAR Part 150, establishes a voluntary, Federal Aviation Administration (FAA) administered program that includes procedures to be followed by airports to assess aircraft noise and land use compatibility. It establishes a single system for the measurement of aircraft (and background) noise, a single system for determining the exposure of individuals to aircraft noise, and a standardized airport noise compatibility planning program. The planning program includes: (1) provisions for the development and submission to the FAA of a Noise Exposure Map (NEM) and Noise Compatibility Program by airport operators; (2) standard units of measure for noise, methods, and analytical techniques for use in airport assessments; (3) identification of land uses which are normally considered compatible (or non-compatible) with various levels of noise around airports based on federal thresholds; and (4) procedures and criteria for FAA approval and disapproval of Noise Compatibility Programs. The Noise Compatibility Program will contain recommendations for noise abatement and mitigation addressing both land use and aircraft operational issues.

The Part 150 Noise Compatibility Study Update that is currently underway will update the existing noise exposure maps by looking at current noise and land use conditions and develop a forecast of future conditions.  In addition, it will update the Noise Compatibility Program to reflect new or updated noise abatement or mitigation measures.

Title 14 of the Code of Federal Regulations Part 150 (“14 CFR Part 150” or simply “Part 150”) establishes a voluntary program, administered by the Federal Aviation Administration (FAA), that includes procedures for airports to assess aircraft noise and land use compatibility. It establishes a single system for evaluating aircraft noise, determining the exposure of individuals to aircraft noise, and standardizing airport noise compatibility planning programs. The Airport Noise Compatibility Planning program includes: (1) provisions for the development and submission to the FAA of the Noise Exposure Maps (NEMs) and Noise Compatibility Program (NCP) by airport operators; (2) standard noise units, methods, and analytical techniques for use in assessments; (3) identification of land uses that are normally considered compatible (or non-compatible) with various levels of aircraft noise based on federal guidelines; and (4) procedures and criteria for FAA approval or disapproval of airport-recommended NCP measures.

The current Ted Stevens Anchorage International Airport (ANC) Part 150 Study will update the NEMs by assessing current aircraft noise and land use compatibility. The Study will develop a 5-year forecast of aircraft operations to assess future conditions. The NCP will contain recommendations for addressing non-compatible land uses identified in the NEMs. NCP measures approved by the FAA could potentially be eligible for federal funding.

The objective of this Part 150 Study is to update the Noise Exposure Maps based on current and forecast future conditions, and to formulate a set of recommendations to be included in the Noise Compatibility Program that addresses non-compatible land uses, as defined by the Day-Night Average Sound Level (DNL) of 65 decibels (dB). The goal of the overall program is for ANC, in consultation with stakeholders, to develop a balanced program to minimize aircraft noise effects on surrounding non-compatible land uses.

Approximately two years. Work on the Part 150 Study started mid-2025. Completion is anticipated in late 2027. Once the documents are accepted by the FAA and published in the Federal Register, it will take up to an additional six months for the FAA to issue their Record of Approval for the Airport-recommended Noise Compatibility Program measures.

ANC is updating its Part 150 Study in collaboration with all stakeholders to assess noise from ANC aircraft operations and land use compatibility with those operations. Since the last update, there have been changes to aircraft fleet mix and activity levels, and updates to the noise model used for analysis, which will all be addressed during the Study.

In 1981, the FAA officially implemented the Day-Night Average Sound Level (DNL) as the primary metric for assessing community exposure to aircraft-related noise. The DNL represents the yearly, 24-hour average sound level, measured in decibels (dB), derived from the cumulative noise levels of the annual-average aircraft operations. During the period from 10 p.m. to 7 a.m., an additional 10 dB are added to each aircraft noise event to account for nighttime noise intrusion. This adjustment recognizes that noise disturbances at night tend to be more disruptive due to lower ambient noise levels and people’s need for sleep. The 24-hour DNL is annualized to reflect noise generated by aircraft operations for an entire year and is identified by “noise contours” showing levels of aircraft noise in 5-dB increments.

DNL is the most widely accepted descriptor for aviation noise because of the following characteristics:

  • DNL is a measurable quantity.
  • DNL can be used by airport planners and the public who are not familiar with acoustics or acoustical theory.
  • DNL provides a simple method to compare the effectiveness of alternative airport scenarios.
  • DNL is based on a substantial body of scientific survey data regarding how people react to noise.


The DNL incorporates A-weighted noise events and/or hourly noise levels. The so-called “A” filter (“A weighting”) generally does the best job of matching human response to most environmental noise sources, including natural sounds and sound from common transportation sources. Because of the correlation with our hearing, the U.S. Environmental Protection Agency (EPA) and nearly every other federal and state agency have adopted A-weighted decibels as the metric for use in describing environmental and transportation noise because surveys have shown that it best mimics how our ears perceive common environmental sounds. Other metrics are used to measure aircraft noise and the supplemental metrics used in the Study are described below; however, only DNL is acceptable as defined by regulation for the Study process.

Noise contours are digitally generated lines that depict either the existing noise exposure levels or forecasted future noise exposure levels represented by a cumulative noise metric. Essentially, a noise contour graphically represents the annual-average aircraft noise exposure (expressed by the Day-Night Average Sound Level, or DNL, metric) through the connection of points with equivalent noise exposure around the airport. They are like geographic contour lines that connect points of equal elevation.

A Part 150 Study uses the DNL contour of 65 decibels (dB) to represent the FAA-defined threshold for identifying non-compatible land uses. Certain noise-sensitive land uses (such as residences, schools, places of worship, etc.) within the DNL contour of 65 dB and greater are non-compatible with aircraft noise. Therefore, noise-sensitive land uses within the 65 dB DNL contour could be eligible for federal funding for FAA-approved noise mitigation measures.

A variety of information is gathered during the Part 150 Study to create an accurate set of aircraft noise exposure contours including: the number of operations, flight paths, type of aircraft, type of aircraft engines, time of day or night, weather conditions, and runway use.

This data is used to generate aircraft noise exposure contours that are overlaid on land use base maps depicting jurisdictional boundaries to create the formal Noise Exposure Map submitted to the FAA for review and acceptance.

AEDT is the model developed by the Federal Aviation Administration (FAA) for evaluating aircraft noise impacts in the communities surrounding airports.  The AEDT uses inputs such as number of operations, aircraft fleet mix (aircraft types), aircraft flight tracks, and flight profiles, time of day of operations and terrain to evaluate aircraft noise.  The AEDT is the model required by the FAA to create the noise contours for use in Part 150 Noise Compatibility Studies.

Sometimes the Day-Night Average Sound Level (DNL) noise metric used in Part 150 Studies is criticized because it averages noise over a 24-hour period for an entire year, which does not accurately portray what people hear on a day-to-day basis. It is true that because the DNL represents noise for an annual-average day, it does not represent what people hear when an aircraft flies over.

Some additional metrics that may be studied include LMAX contours (the maximum sound level) for single aircraft landing-takeoff cycles in each traffic flow direction for critical aircraft that operate at ANC today and in the future. Another metric that could be included is the number of events that generate a maximum noise level above 75 decibels (dB), known as the N75 noise metric. This metric is helpful in illustrating how many times per day noise events occur that can result in some degree of interference. Finally, representative receptor analysis could be completed, which presents the noise levels in terms of various metrics at example sites around the Airport. The metrics above could be presented for certain supplemental information, based on stakeholder coordination and the operational alternatives examined. However, these metrics will be used for informational purposes only. The DNL metric is required to be used in the Part 150 analysis. The noise mitigation measures within this Study are approved or disapproved based on DNL alone.

In accordance with FAA guidance, a Part 150 Study relies on the Day-Night Average Sound Level (DNL) noise metric to assess land use compatibility. The FAA considers all land uses compatible with aircraft noise below 65 decibels (dB) DNL. The Part 150 Study will assess land uses exposed to a DNL of 65 dB or greater to identify non-compatible land uses according to Table 1 of Appendix A of the Part 150 regulation. Noise-sensitive land uses exposed to a DNL of 65 dB or greater could be eligible for federal funding for noise mitigation measures. Such measures and potential eligibility will be assessed in the Part 150 Study.

Yes, all aircraft operating at Ted Stevens International Airport will be included in the modeling, as well as those operating out of Lake Hood Seaplane Base and the Lake Hood gravel runway, to accurately depict the type of aircraft operating, the location of those operations, as well as the number of aircraft operating.  Because of the seasonal use of Lake Hood Seaplane base, seasonal noise monitoring will be conducted during the summer and winter. These inputs help inform the study, and all flight tracks for a full year will be used as inputs into the AEDT model.

No. The Study includes aircraft that operate from ANC. The Study does not include sources of non-aviation noise, such as roadway traffic, and railway activity.

Flight tracks will be examined as part of the Study. The Study may make recommendations on flight track changes; however, flight pattern procedures are under the sole purview of the FAA, considering operational, safety, and air traffic control procedures. The airport operator does not have authority to regulate flight patterns. Full development of approved new procedures would be completed by the FAA after the completion of the Study and appropriate environmental documentation.

The Airport, FAA, stakeholders, and the public can all be involved in the Part 150 Study process. A Study Advisory Committee (SAC) has been formed to work closely with airport staff and the consultant team. The SAC includes representatives from the local jurisdictions, aviation stakeholders, businesses, and the communities. The role of the SAC is to review information, provide feedback, discuss noise abatement alternatives, and advise the Airport on the adoption of Noise Compatibility Program (NCP) measures to address noise and land use compatibility. Additionally, public information meetings/workshops will be held at key points throughout the Study. Public meetings will be announced on this website. The public can also provide feedback at any time through the comment form on this website. All comments will be sent to the Study team and be considered throughout the process to help inform the Study.

Study Advisory Committee Composition, July 2025

Public information meetings will be held at key times during the Study process. These meetings will primarily be conducted in an “open house” format to allow attendees to ask questions of the subject matter experts to better understand the information being presented. Various alternatives will be presented, and draft recommendations will be available for review. You will have the opportunity to ask questions and express any concerns or comments to the study team during meetings and on this website at any time. Meeting dates will be advertised through newspaper advertisements, email outreach, social media and posted on the Study website. This website will also be updated at key points in the Study. The study team will continually refine the community engagement plan and look for ways to get the information out to a broader audience.

All comments submitted will be taken into consideration during this Study. Those submitted during the official public comment period for the Noise Exposure Maps and Noise Compatibility Program during and following the public hearing will be formally included and responded to in the final report documents. The most frequently asked questions will be addressed as part of these FAQs and all comments are reviewed by the Study team and integrated continually in the process as it moves forward.

The FAA requires use of its Aviation Environmental Design Tool (AEDT) to generate noise exposure contours from aircraft operations to assess land use compatibility around airports. AEDT is a software system that models aircraft performance in space and time to estimate fuel consumption, emissions, noise, and air quality consequences. The AEDT uses the following aircraft operational data when generating noise exposure contours from aircraft operations:

  • Total number of aircraft operations
  • Aircraft operations by type of aircraft
  • Aircraft operations by time of day
  • Aircraft operations by runway use
  • Aircraft operations by flight track
  • Aircraft operational procedures, including touch-and-go operations
  • Aircraft auxiliary power unit and ground power unit usage


The FAA requires the latest available AEDT model be used to generate the noise contours for use in Part 150 Studies, which at the onset of noise modeling for this ANC Part 150 Study was version 3g. If an update is pushed out prior to modeling starting, the newest model may be used.

To ensure consistency among all U.S. airports, the FAA requires the use of its noise model, Aviation Environmental Design Tool (AEDT), to generate aircraft noise exposure contours. The noise algorithms in AEDT use the results of measurement data provided to them via the aircraft certification process.

Noise measurements typically occur at a relatively small number of discrete monitoring locations not intended to generate contours but rather to understand specific single event levels at locations. For consistency purposes, the FAA does not allow noise measurements to validate or calibrate the model, but noise monitoring can assist in understanding community concerns.

Noise measurements are intended to be done in communities with noise concerns surrounding the airport. The results of the noise measurements will not determine the location or extent of the noise exposure contours from aircraft operations as the FAA requires solely the use of their noise model. Measurements may help ensure we get the noise model inputs as accurate as possible.

Grant assurances are contract obligations that airport owners agree to when they accept funds from FAA-administered airport financial assistance programs. These are meant to protect the government’s investment and the public’s interest in using public airports. For example, some of the 39 grant assurances are:

  • The airport will be open to the public and not discriminate against anyone who wants to use it.
  • The airport will charge reasonable fees and not give unfair advantages to any airlines or businesses.
  • The airport will maintain and operate the facilities safely and efficiently.
  • The airport will use the money or land only for airport purposes.
  • The airport will follow environmental laws and regulations.
  • The airport will cooperate with the government in case of emergencies or national security issues.


These grant assurances become legally binding when the airport owners accept the funds or property. The government can enforce these grant assurances by withholding future funds, taking back the property, requiring repayment of funds, or declaring the airport in noncompliance, along with other measures. This is important in the context of noise, because as it is a public use airport, grant assurances do not allow an airport to restrict aircraft operations.

The regulation of aircraft noise levels has been preempted by the federal government as aircraft are integral to the National Air Transportation System. The FAA has exclusive authority to certify aircraft and pilots, and to control aircraft in flight and on the ground, along with regulating aircraft noise levels and emission levels. Local governments can promote compatible land use through zoning, prohibit non-compatible land uses, and require real estate disclosure. They cannot directly restrict aircraft operations or regulate the routes, rates, or service of air carriers.

CFR Parts 36, 161, and 91 are all parts of Title 14 of the Code of Federal Regulations (CFR), which deals with aeronautics and space. These Parts specifically relate to aircraft noise in the following ways:

  1. CFR Part 36: Titled “Noise Standards: Aircraft Type and Airworthiness Certification,” Part 36 defines the U.S. noise standards for aircraft. It prescribes the noise measurement and evaluation procedures, noise limits, and documentation requirements that must be met for certification for different types of aircraft, including transport category large airplanes, jet airplanes, propeller-driven small airplanes, helicopters, and tiltrotors. The FAA publishes certified noise levels in Advisory Circular 36-1H, Noise Levels for U.S Certificated and Foreign Aircraft.
  2. CFR Part 161: Titled “Notice and Approval of Airport Noise and Access Restrictions,” Part 161 implements the Airport Noise and Capacity Act (ANCA) of 1990. It prescribes the notice requirements and procedures for airport operators who wish to implement noise and access restrictions on Stage 2 and Stage 3 (and greater) aircraft. To date, there have been no approved Part 161 Studies in the nation that restrict Stage 3 and greater aircraft, which account for most, if not all, aircraft flying today. There are very few, if any, Stage 2 aircraft certified prior to 1977 remaining in the U.S. aircraft fleet.
  3. CFR Part 91: Titled “General Operating and Flight Rules,” Part 91 prescribes general operating and flight rules, including noise limits for aircraft operations. It is less restrictive compared to other parts of the Federal Aviation Regulations and primarily applies to general aviation, non-commercial, and private flights. Subpart I of CFR Part 91 specifically prescribes operating noise limits and related requirements for the operation of civil aircraft in the United States.


These parts of the CFR provide the regulatory framework for managing aircraft noise in the United States, balancing the operational needs of the aviation industry with the noise exposure on communities surrounding airports.

The Neighborhood Environmental Survey (NES), conducted by the Federal Aviation Administration (FAA), is a key component of the FAA’s ongoing research into aircraft noise. This nationwide survey aims to gauge the level of annoyance caused by aircraft noise. The FAA is currently working through comments submitted on the NES; the FAA’s plans for the results of the NES remain uncertain at this point. For purposes of this Study, DNL of 65 decibels is the threshold for non-compatibility that is required for alternatives analysis. The study team will examine other contours specifically for land use planning purposes and will continue to monitor any developments that may be released from the FAA regarding the NES.

Yes. Lake Hood is included in the scope of this Study.

No. It is important to note that the 14 CFR Part 150 guidelines stipulate that only aircraft operations that originate or end at the Study airport can be incorporated into the Study process. Overflight operations from other airports or facilities are not included.  

No. The focus of the Study is land use compatibility.

ANC does not have the ability to control the number or type of aircraft that operate at the Airport, to dictate the runways aircraft use, to control aircraft flight paths, or to limit the time of day or night that aircraft take off or land. The FAA and the pilots determine which runways and aircraft flight paths are used. The aircraft operators determine the number of flights and the types of planes that are flown. Additionally, federal law prevents the airport sponsor from limiting the hours of the day or night when aircraft are allowed to operate.

Potential mitigation measures from a Part 150 project fall within three categories: operational, land use, and administrative.

Mitigation measures for operational alternatives include:

Aircraft Operation measures such as departure thrust cutback (departure climb profile) and potential modifications to flight procedures.

Airport and Airspace Use measures like preferential runway use system, power and flap settings, denial of use of airport for aircraft not meeting federal noise standards, and measures limited by Part 161 (Part 161 restricts airport’s ability to regulate airport access based on noise) which include capacity limits based on defined noise limits, landing fees based on noise, complete or partial curfews, a ban on all jet aircraft, and touch-and-go restriction.

Airport Facility measures such as a new runway in a different orientation, runway extensions, high-speed exit taxiways, ground run-up enclosures, and noise barriers.

Land use mitigation measures include:

  • Corrective Land Use measures like acquisition of land or interest therein and sound insulation.
  • Preventive Land Use measures including zoning, easements, transfer of development rights, building code modifications, capital improvements program, subdivision regulations, and comprehensive planning.

Administrative mitigation measures include:

  • Noise Program Management measures such as a noise monitoring program, establishment of a community noise round table committee, and a voluntary fly quiet program.

Ted Stevens Anchorage International Airport (ANC) has several operational procedures in place to help reduce aircraft noise impacts on surrounding communities. These current noise mitigation measures include:

  • Preferential Runway Program which directs aircraft to use specific runways that minimize noise exposure to residential areas when conditions allow.
  • Noise Abatement Departure Profiles (NADP) encourages aircraft departing runways 7R/L and 15 use the NADP Close-In procedure to reduce noise during initial climb.
  • Training Flight Procedures for circle-to-land training operations are directed to use Runways 7R/L and circle to land on Runway 33 to reduce overflights of noise-sensitive areas.
  • During Quiet Hours (10:00 PM – 7:00 AM) the following measures are in effect:
    • No engine run-ups above idle power in ramp areas
    • Reverse thrust on landing should be minimized
    • Training flight operations are discouraged

Within Section 8 of the Ted Stevens Anchorage International Airport Operations Manual (dated March 7, 2025), pilots are instructed to maintain a minimum traffic altitude of 1,000 feet over residential neighborhoods while operating at Lake Hood. This requirement aligns with FAR 91.119, which sets the minimum safe operating altitudes for general aviation aircraft, ensuring a safe buffer over populated areas.

It is important to note that when an aircraft is taking off or landing, the precise altitude is at the discretion of the pilot in command. Factors such as the specific type of aircraft and directions issued by air traffic control may also influence the altitude during these maneuvers.

Please refer to the ANC Airport Operations Manual 2025

The project team will select up to six sites for long-term noise measurements. These noise monitors will collect one-second noise level data for a complete seven 24-hour days. The project team will have a few spare noise monitors available for short-term measurements that will be set out for one to six hours on a particular day to perhaps capture some unusual or specific aircraft operations. The actual locations will be selected from those property owners that signed up at the May 2025 public workshop. We will also select alternate properties in case the main locations are determined to be unsuitable for measurement of aircraft noise when we arrive the property. The information collected will include single-event noise levels and daily cumulative noise levels (long-term sites only) and be reported in the report documentation.

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Connect with the Project Team

Airport
  • Ian Moore, ACE
    Airport Project Manager
  • Taylor J. Beardsley, C.M.
    Airport Assistant Project Manager
Mead & Hunt
  • Kate Andrus
    Consultant Project Manager
  • Corbett Smith
    Consultant Assistant Project Manager
Agnew::Beck Consulting