Airport Noise Abatement

Frequently Asked Questions About Settlement

Have the cities settled their lawsuit against the MAC?
How can I check to see if I might qualify for noise mitigation under the settlement?

How are qualifying households officially notified?

What kind of work is authorized by the settlement?

Who picks the contractor?

What’s a noise contour?

What is DNL?

What is a noise exposure map?

What is Part 150?

What’s a noise abatement program?

What’s the significance of the year attached to a DNL noise contour?

Can the MAC still be sued over noise? 

Have the cities settled their lawsuit against the Metropolitan Airports
Commission?

Yes. The cities of Minneapolis, Richfield, Eagan and the Minneapolis Public Housing Authority and the Metropolitan Airports Commission have reached a settlement which is detailed in the Consent Decree. The settlement that was reached on Oct. 16 and approved on Oct. 19, 2007 had three conditions, the last of which was satisfied on Jan. 15, 2008. The noise mitigation program in the class action settlement matches the terms of the cities’ settlement.

How can I check to see if I might qualify for noise mitigation under the proposed settlement?

The first source to check is the Metropolitan Airports Commission’s interactive settlement map. Type in your home address, and the map will show the address in relation to the 2007 DNL (Day/Night Noise Level) contours. Because the interactive maps show approximate addresses, additional checking is needed if you live near the 60 contour.

The City of Minneapolis has posted the MACs final maps of the 2007 contour on this website. Blocks on the map shaded in green, purple or pink are eligible for some degree of noise mitigation. According to the Consent Decree, noise contours are determined on a block-by-block basis. You are in the highest contour that intersects with your block. If it isn’t clear from the MAC’s map whether your home is eligible for noise mitigation, contact the Metropolitan Airports Commission at www.macnoise.com.

Please be aware that only the Metropolitan Airports Commission’s final map is official for the purposes of determining eligibility for noise mitigation.

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How are qualifying households officially notified that they’re eligible for noise mitigation under the settlement?

The Metropolitan Airports Commission (MAC) will notify qualifying households by letter. Official notification from the MAC will take place over a period of years as it implements the provisions of the Consent Decree.

Households in the higher 2007 noise contours (63 - 65 DNL) will receive official notices sooner than households in the lower 2007 noise contours (60 - 62 DNL). It is anticipated that notification to the highest noise contours could begin by May 1, 2008 with final notification completed by July 1, 2009.

Even within the same noise contour, notification will be done in stages. Notices will be sent to a manageable of number of households inviting them to an orientation meeting. After one group completes its orientation, the notification process would proceed to the next group until all qualifying households in a contour are notified.

Homeowners in the area between the 2007 and 2005 60 DNL noise contours will receive notification by Feb. 1, 2010 and will have until Sep. 1, 2014 to request reimbursement for approved mitigation projects (see immediately below for more information about what kind of work is authorized).

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What kind of work is authorized by the settlement?

The settlement authorizes different types of noise mitigation programs depending on the home’s location on the Consent Decree’s official map.

One, two and three-family homes in the 63 through 65+ DNL in the 2007 noise contours

Homes in these DNL ranges will receive a five decibel noise reduction package. Work could include central air conditioning, wall insulation, new windows and doors, roof baffles, duct work, etc. Noise mitigation might not necessarily include all of these or any particular one of these. Rather, the work would include actions deemed by MAC officials to reduce jet noise, on average, by five decibels inside a home. Work would be done between Nov. 1, 2008, and Dec. 31, 2009. This program involves approximately 450 homes.

One, two and three-family homes in the 60 through 62 DNL in the 2007 noise contours

Homeowners in these contours may choose between the two options listed below.

1. The homeowner could opt to receive central air conditioning if the home does not have air conditioning. Homes that receive central air conditioning would also be eligible for other noise mitigation improvements up to a value of $4,000. Only noise mitigation improvements on a specific list of noise mitigation products installed by MAC-approved contractors would be allowed.

2. If the home already has central air conditioning or if the owner does not want central air conditioning, the owner would be allowed to select items from a pre-established menu of noise mitigation products and services adding up to a value of no more than $14,000. The products and services on this menu will be determined by the Metropolitan Airports Commission. This list is likely to include insulation, sealing and caulking, acoustical windows and storms, etc. Work must be done by a MAC-approved contractor.

Work would be done between Dec. 1, 2008, and Dec. 1, 2012. It is expected that work would generally be done first in the higher noise DNLs and then proceed through the lower noise DNLs. These noise contours encompass more than 5,300 homes.

Apartment and condominium buildings with four or more dwelling units in the 60 through 62 DNL in the 2007 noise contours

Owners in this area are eligible to have permanent through-the-wall air conditioning units installed if they don’t already have operational through-the-wall air conditioning. Each dwelling is also eligible to receive an acoustical air conditioning cover. Work would be done between Dec. 1, 2008, and Dec. 1, 2010 (or possibly sooner). This involves approximately 1,930 dwelling units.

One, two and three-family homes located between the 2007 and 2005 60 DNL noise contours

Homeowners are eligible to receive reimbursement of noise abatement improvements from a list of improvements that will be determined by the Metropolitan Airports Commission. The work will have to be done after the date the Consent Decree is finalized and before Sept. 1, 2014. The list of improvements eligible for reimbursement under this program will be determined by the Metropolitan Airports Commission, and all work must be done by a licensed contractor. Anyone who has work done before the list is finalized by the MAC assumes the full risk that their completed mitigation work may not be on the MAC’s list of approved noise mitigation improvements, and, therefore, does not qualify for reimbursement. (Information on this program appears on pages 24 to 28 of the Consent Decree; readers are advised to be aware of the definitions starting on page 4.)

The total amount available for this reimbursement program is not yet known. This program is to be funded out of a $7 million fund that will also fund noise mitigation for homes whose owners had decided not to participate in the earlier noise mitigation program, but which now have new owners who want to participate in the new program. After work is done on these "opt out/opt in" homes, the remaining funds will be divided between the one, two and three family homes located between the 2007 and 2005 60 DNL noise contours. It is roughly estimated that there may be about $2,500 per home. This may change, however, depending on the number of homes improved through the "opt out/opt in" program. The number of homes that could be eligible for reimbursement for noise mitigation work under this portion of the settlement is estimated to be about 2,300 homes. For additional information, check the Consent Decree Summary.

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Who picks the contractor?

Homeowners in the 64 – 60 DNL in the 2007 noise contours

Homeowners between the 2005 and 2007 60 DNL noise contours

Additional information can be found in the Consent Decree.

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What’s a noise contour?

Noise contours are lines placed on a map to represent equal noise levels.

Airport noise contours are usually based on future projections - not actual aircraft noise readings. Official noise contour maps submitted to FAA are not based on actual aircraft noise readings. FAA-approved noise contour maps are generated from a computer model called the Integrated Noise Model. This model takes into consideration the volume of traffic, type of aircraft, runway use, time of day operations occur, flight tracks and other data in calculating noise contours.

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What is DNL?

DNL, an acronym for Day/Night Noise Level, is a system that models the average aircraft noise levels over a 24 hour period, typically an average day over the course of a year. It is based on a computer model.

The DNL metric penalizes the noise level of aircraft operations that occur between 10 p.m. and 7 a.m. by adding ten decibels to the noise level to account for the increased annoyance when ambient noise levels are lower and people are sleeping. DNL is the measurement metric that the Federal Aviation Administration (FAA) has chosen to use around airports to evaluate noise mitigation programs being funded pursuant to FAA rules. There are a variety of other noise metrics that are used for various purposes in other parts of the world. DNL, however, is the principle noise metric used by the FAA.

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What is a noise exposure map?

A noise exposure map is a map that depicts the various noise contours surrounding an airport and defines the area where noise mitigation may be necessary. The noise exposure map takes into account the time of day, flight directions, expected use of the various runways, number of daily flights and aircraft type. The noise exposure maps are developed using the Federal Aviation Administrations computer model called the Integrated Noise Model.

The noise exposure map used for determining mitigation is typically based on a five year projection of anticipated airport operations and the resulting noise exposure. These predicted noise impacts are used to develop noise mitigation plans under Part 150 regulations.

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What is Part 150?

Part 150 is a partial Code of Federal Regulations citation to a voluntary program which an airport operator can undertake to mitigate noise. When approved by the FAA, it allows for the use of federal Airport Improvement Program funds for noise mitigation.

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What’s a noise abatement program?

A noise abatement program is an effort by an airport operator to reduce noise levels around an airport. Programs submitted pursuant to Part 150 are referred to as a Noise Compatibility Program (NCP) and often include both operational measures and land use measures aimed at achieving greater compatibility between operation of the airport and land use in neighboring communities.

The airport operator uses a noise exposure map to identify the area of noise impacts associated with a particular scenario. The various elements of the noise compatibility program are then evaluated to determine the impacts on the noise contours with the intent of minimizing the area of noise impact.

Often, federal Airport Improvement Program funds can be used to pay for some corrective actions (e.g. acquiring homes or insulating existing homes) required for noise mitigation.

Examples of corrective actions that can reduce noise in buildings near airports include:

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What’s the significance of the year attached to a DNL noise contour?

When airports apply for noise mitigation they are required by federal rules to use a DNL noise metric that projects into the future five years. The year listed is the projected year. Over time a number of different DNL contour lines have been drawn, each with different projected dates. The most current DNL contours that have been submitted to and approved by the FAA for Minneapolis-St. Paul International Airport are the 2007 contours.

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Can the MAC still be sued over noise?

Cities Lawsuit

The cities involved in the settlement, including the City of Minneapolis and Minneapolis Public Housing Authority, have agreed that they will not sue the Metropolitan Airports Commission (MAC) over airport noise.

There are several exceptions, however. The cities may be able to sue if the average DNL for an area goes up by two or more decibels in a year or if MAC builds a new runway or extends a runway that causes noise of 60 decibels or above in residential areas. However, being able to sue does not necessarily mean there is a good cause of action recognized by law.

Homeowners who participate in the noise mitigation program established by the proposed settlement in the cities’ lawsuit will be asked to sign a release.

Separate Class Action Lawsuit

Homeowners who are members of the class and who did not opt out of that lawsuit are bound by the class action settlement which mirrors the terms of the cities settlement. For more information about the separate class action lawsuit, check the Zimmerman Reed website.

Homeowners who are not members of the plaintiffs’ class from the class action lawsuit and who have not signed releases as part of their participation in the cities settlement may sue over noise if they have a cause of action recognized by the law that they believe they can prove in court. You must consult your own attorney to determine what rights you may have in this regard.

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Updated Jan. 17 2007

Last updated Jun. 8, 2012