As FAA's primary metric for aviation noise analysis, the FAA has determined that the cumulative noise energy exposure of individuals to noise resulting from aviation activities must be established in terms of the day-night average sound level (DNL) in decibels (dB). The 65 DNL is the Federal significance threshold for aircraft noise exposure.
What is the 65 DNL?
FAA Response: The O’Hare Noise Compatibility Commission (ONCC) developed an animation showing the estimated change in O'Hare noise contours over the years. The animation also illustrates the projected noise contours when OMP is complete. You can find it on the ONCC home page at: http://www.oharenoise.org/
Where can I find the projected contour map for Build Out (all runways completed)?
FAA Response: Noise contours depict levels of aircraft noise surrounding an airport. The FAA analyzed noise impacts for the OMP in the EIS using established aviation industry methods. The noise contour developed for the OMP for build-out conditions is called the Build-Out Noise Contour. The noise contour is used for land use compatibility and noise exposure and mitigation purposes. The Build-Out Noise Contour was approved on September 30, 2005, as part of the Record of Decision (ROD).
What is a noise contour?
How do I complain about airplane noise?
The Chicago Department of Aviation maintains a toll-free hotline at 1-800-435-9569 and an Aircraft Noise Complaint Form for citizens to report concern about particular aircraft events or aircraft noise levels in general. Tallies of noise complaints appear in the monthly Airport Noise Management System report.
When the FAA issued the ROD, the ROD identified the 65 DNL Build-Out Noise Contour as the noise contour to be used for sound insulation purposes. Noise contours for interim conditions are not used for sound insulation purposes. Each home must also meet additional eligibility criteria as established by the City and the ONCC. For more information, please call the City’s Residential Inquiry Line at 773.894.3255 or visit the Property Locator on the City’s website at https://gisapps.cityofchicago.org/aviation/.
Does my home qualify for sound insulation?
FAA Response: The FAA’s Integrated Noise Model (INM) produces DNL noise contours. INM is a computer model used to develop aircraft noise exposure maps. INM is the industry standard for calculating the level of aircraft noise at and around airports. INM uses a database of aircraft noise characteristics to predict DNL based on user input on the types and number of aircraft operations, annual average airport operating conditions, average aircraft performance, and aircraft flight patterns.