MAC Goes the Extra Mile for Noise Data Collection

Members of the Minneapolis-St. Paul International Airport (MSP) Noise Oversight Committee (NOC) voted to support extra efforts by Metropolitan Airports Commission (MAC) Noise Program staff to evaluate aircraft noise levels generated by aircraft overflying areas of Eagan.

The MAC collects aircraft and community noise levels 24-hours per day through an array of 39 remote monitoring towers (RMT) positioned in neighborhoods surrounding MSP. It is the most extensive noise data collection system used by airports in the United States. Each RMT location was carefully evaluated before the equipment was installed.

The MAC analyzes the data collected at each RMT and reports the levels of community noise and aircraft noise recorded on a monthly basis. A validation study conducted in 2012 concluded there is a high level of accuracy of data being collected by the RMT system. However, as neighborhoods change and aircraft become quieter it is important to evaluate the contributions of community noise compared to aircraft noise to ensure quality aircraft noise data are being collected. For example, RMT locations #25 and #37 in Eagan are recording many instances of ground vehicle noise levels often that are louder than the aircraft overflying those areas. When this happens, the aircraft sound data are polluted by other noise sources.

Mobile noise monitoring equipment is often used to help study aircraft versus community noise contributions. Requests for mobile noise monitoring in the communities surrounding MSP must be coordinated through a current NOC member and submitted to the MAC Noise Program Office for evaluation. As such, the MAC considered a recent proposal by the Eagan Airport Relations Commission to study aircraft versus community noise levels in two alternate locations in the City of Eagan and compare the quality of established levels to the levels collected at RMTs #25 and #37.

MAC staff recommended to NOC members that a study be conducted in the City of Eagan over a two-week summertime period to ensure noise is captured when MSP is operating in a south flow, when Runways 17, 12L and 12R are being used for departures, to determine if gaps in the RMT coverage area currently exist. Further, the MAC will investigate if RMTs #25 and #37, close to Interstate 35E, are properly located to best monitor aircraft noise given the ambient freeway noise. Ultimately, the data collected during this mobile noise monitoring study will inform potential recommendations about alternative placements for the permanent towers if the mobile monitors document that gaps exist in the current system.

The Federal Aviation Administration (FAA) does not allow airports to use aircraft noise data recorded by the mobile noise monitoring equipment or the permanent RMTs to establish eligibility for residential noise mitigation. Click here to view more information on eligibility for the MAC's noise mitigation program: https://www.macnoise.com/faq/how-much-noise-qualifies-my-home-mac-noise-...

More information about the MAC’s RMT system may be found here: https://www.macnoise.com/our-neighbors/mobile-noise-monitoring