Announcements
A public hearing was held on October 14th and 15th, 2015 to accept public comment on the Draft NEM Update. Click here for more information.
Contact Information
For information about the NEM update or the Airport's Noise Program, contact:
Kevin Hennessey
Community Program Manager
CLT Center
5601 Wilkinson Blvd.
Charlotte, NC 28208
(704) 359-HEAR (4327)
To submit a formal noise complaint to Charlotte Douglas International Airport, please call 704-359-HEAR(4327) or
click here.
Frequently Asked Questions
- What are Noise Exposure Maps?
- What is a Noise Exposure Map Update?
- What is DNL?
- How is a Noise Exposure Map Update Different from a Noise Compatibility Study?
- Why prepare a Noise Exposure Map Update?
- What has CLT done to mitigate aircraft noise impacts?
- What is the Integrated Noise Model?
- What is the purpose of noise monitoring in a Noise Exposure Map Update?
- How long will the Noise Exposure Map Update take to complete?
- How do I comment on the study?
- Can operations be restricted at Charlotte Douglas International Airport?
- Can flight paths or altitudes of aircraft on arrival be modified to direct overflights away from my house?
- How can I get involved with the Noise Exposure Map Update and where can I find information?
- What areas are included in the Noise Exposure Map Update Study?
What are Noise Exposure Maps?
Noise Exposure Maps (NEMs) identify the noise impacts of current operating conditions and projected future conditions. Operational conditions included within this analysis will be airport departure and arrival procedures, daytime and nighttime flights, and aircraft engine run-ups. Aircraft noise is depicted on the NEMs as noise contours, which show the average noise levels around the airport.
What is a Noise Exposure Map Update?
A Noise Exposure Map (NEM) Update is designed to identify noise-sensitive land uses surrounding an airport for existing conditions and for five years in the future. For the purpose of an NEM Update, noise-sensitive land uses are generally defined as residences or public use facilities (libraries, places of worship, schools, nursing homes, and hospitals) within the 65 Day-Night Average Sound Level (DNL) noise contour, the area the Federal Aviation Administration defines as significantly impacted by aircraft noise.
What is DNL?
The Day-Night Average Sound Level (DNL) metric describes the total noise exposure during a given period. DNL is a metric used for predicting the average long term noise exposure on a population. In computing DNL, an extra weight of
10 decibels (dB) is assigned to any sound levels occurring between the hours of 10:00 p.m. and 7:00 a.m. This is intended to account for the greater impact that nighttime noise is presumed to cause for most people. This extra weight calculates one nighttime noise event as the equivalent to 10 daytime events of the same magnitude.
Per Federal Aviation Administration guidelines, 65 DNL is the threshold at which noise sensitive land uses (residences, schools, places of worship, libraries, hospitals) are considered incompatible with aircraft noise. It is important to note that DNL measures the average noise level over a 24-hour period. This method takes into account both the total noise as well as the frequency of noise from aircraft events. Because DNL measures average noise, it is possible that single aircraft events have a maximum noise level greater than 65 decibels at a location that experiences average noise exposure of less than 65 DNL.
How is a Noise Exposure Map Update Different from a Noise Compatibility Study?
Like Noise Exposure Map (NEM) Updates, Noise Compatibility Studies identify noise-sensitive land uses surrounding an airport. However a Noise Compatibility Study also recommends measures to both correct existing incompatible land uses and to prevent future incompatibilities. Both a NEM and a Noise Compatibility Study are guided by Federal Aviation Administration regulations found in 14 CFR Part 150.
Why prepare a Noise Exposure Map Update?
The Noise Exposure Maps (NEM) for Charlotte Douglas International Airport were last updated in 1996. The Federal Aviation Administration recommends that NEMs be updated periodically to take into consideration changes that may have occurred at the airport, such as aircraft fleet changes or an increase or decrease in aircraft operations.
What has CLT done to mitigate aircraft noise impacts?
To date, Charlotte Douglas International Airport (CLT) has sound insulated over 1,000 homes. This forthcoming Noise Exposure Map (NEM) Update will prepare new NEMs that identify properties that are within the 65 DNL noise level based on current conditions and conditions expected five years into the future at CLT. These updated NEMs will be the basis for the continuation of the residential sound insulation program at CLT. Based on Federal guidelines, CLT can only receive Federal funding to sound insulate homes that are inside the 65 DNL noise exposure contour.
What is the Integrated Noise Model?
The Federal Aviation Administration (FAA) has developed the Integrated Noise Model (INM) for evaluating aircraft noise impacts in the vicinity of airports. The INM is the FAA's standard tool for determining the predicted noise exposure in the vicinity of airports. The FAA requires the use of the INM to develop noise exposure contours in Noise Exposure Map Updates.
The INM utilizes flight track information, types of aircraft using the airport, aircraft flight profiles, runway use and terrain as inputs. The INM produces noise exposure contours measured in DNL that are used for land use compatibility maps.
What is the purpose of noise monitoring in a Noise Exposure Map Update?
Field noise monitoring is being conducted as part of this Noise Exposure Map (NEM) Update. Noise measurement data cannot be used as a substitute for computer-generated noise contours. However, when generating noise contours, the noise measurements are used to refine the input data into the Integrated Noise Model (INM). The actual noise monitoring measurements will be compared with pre-existing database information related to aircraft noise level and performance characteristics in the INM. The information collected will include acoustical output as well as flight track data (the aircraft's three-dimensional location) relative to the noise measurement site on the ground. This information will be used to ensure that the input data into the INM is as accurate as possible. Over 35 locations around CLT were used to collect noise measurements.
How long will the Noise Exposure Map Update take to complete?
The Noise Exposure Map Update began in the spring of 2014. The Map Update is expected to be submitted to the Federal Aviation Administration for review by spring 2015.
How do I comment on the study?
The comment period is over.
Can operations be restricted at Charlotte Douglas International Airport?
The Federal Aviation Administration (FAA) is the only entity that can manage aircraft runway operations or aircraft in flight at Charlotte Douglas International Airport. Furthermore, as a recipient of FAA grant funds, the Airport must abide by FAA-imposed obligations and conditions. A specific condition prohibits the Airport from restricting or limiting airfield access based on noise or time of day. Airlines have the ability to set flight schedules based on demand at the airport and while airlines may voluntarily limit operations during the late night and early morning, there is no mandatory curfew for aircraft operations at Charlotte Douglas International Airport.
Can flight paths or altitudes of aircraft on arrival be modified to direct overflights away from my house?
The Federal Aviation Administration (FAA) designs flight corridors and aircraft arrival and departure procedures to maximize operational efficiency while maintaining aircraft safety. The Airport has no control over how the FAA designs the airspace around Charlotte.
How can I get involved with the Noise Exposure Map Update and where can I find information?
A series of Public Information Meetings will be held at key milestones during the Noise Exposure Map Update. Open to all, each meeting is designed to make it easy for the public to provide input, ask questions and offer recommendations in a more personal setting. Upcoming public meeting dates will be posted online here: www.airportsites.net/CLT-NEM/meetings.htm
What areas are included in the Noise Exposure Map Update Study?
This Noise Exposure Map Update study includes the regional area in the vicinity of the Airport that may experience broader effects from aircraft overflights, which includes areas that are outside the 65 DNL noise exposure contour. However, per Federal Aviation Administration guidelines, 65 DNL is the threshold at which noise-sensitive land uses (residences, schools, places of worship, libraries, hospitals) are considered potentially incompatible with aircraft noise.