Annual Sound Study Report

Air Traffic Control Tower is staffed. The three-year average is impacted by higher than typical levels in August 2 2022 that were reported by the FAA due to increased flight training and a closure of South St. Paul Airport during the 2022 study period. As reported by the FAA, there were 4,039 STP flight operations in August 2024 with 925 occurring during the 2024 study period, compared with 4,001 STP flight operations in August 2023, and 1,007 operations occurring during the 2023 study period. Flight training at STP generates multiple operations during a single flight as pilots practice their takeoffs and landings (called touch and go operations) for proficiency. It is normal and expected that the airport will be busier in the summer when increased flight training and recreational flying take place. As such, the STP Sound Study is conducted during this time of year to capture as much aircraft activity as possible. The MAC Noise and Operations Monitoring System (MACNOMS) collects and reports flight track data. Until recently, MACNOMS counted an operation only when a flight arrived at the airport or departed from the airport. This means that a single training flight that included numerous consecutive takeoffs and landings would only be counted for its initial takeoff and its final landing. While the process for counting MACNOMS operations has improved over time, discrepancies remain between FAA reported operations and MACNOMS. During the 2024 study period, MACNOMS data show 919 total operations at STP with 463 arrivals and 456 departures. Table 2.1 shows the number of operations on each STP runway per day. The highest levels of STP runway use occurred on Runway 14 with 290 arrivals and 276 departures. Table 2.1: STP Aircraft Activity per Runway each Day during the Study Period Runway 13-Aug 14-Aug 15-Aug 16-Aug 17-Aug 18-Aug 19-Aug Runway Total STP Arrivals 9 - - - - - - - - 13 1 - 2 - 7 1 - 11 14 95 63 47 3 3 9 70 290 27 - - 2 1 2 1 - 6 31 1 - - - 16 1 1 19 32 4 3 9 44 28 47 2 137 STP Departures 9 - 2 - - 1 2 1 6 13 2 - - - 4 1 - 7 14 89 58 - - 3 8 66 276 27 2 - 1 - - - - 3 31 - - 1 - 21 1 - 23 32 5 3 8 55 27 40 3 141 Daily Total 199 129 122 103 112 111 143 919 Runway 14/32 was used for 92 percent of the activity during the study period, Runway 13/31 was used 7 percent and Runway 9/27 was used 2 percent. Figure 2.1 shows the STP flight tracks for daytime operations. There were 73 flights that operated between the hours of 10:00 P.M. and 7:00 A.M.; of those flights 37 were arrivals and 36 were departures. Figures 2.2 depicts STP nighttime activity during the study period. Weather during the study week was desirable for flying with typical mid-summer wind and temperature patterns, and very little precipitation occurred. Weather conditions (e.g., temperature, precipitation, wind, etc.) affect airport activity, runway use decisions and aircraft performance. In addition to operational factors, weather conditions can also affect the way sound is transmitted and observed. As such, weather data are documented during the study period and a summary of daily weather conditions is available in Appendix A.2. 3 Figure 2.1: STP Daytime (7:00 A.M to 10:00 P.M.) Operations During Study Period 4 Figure 2.2: STP Nighttime (10:00 PM to 7:00 AM) Operations During Study Period 7 3.0 Sound Modeling Since 2007, sound analysis has been conducted for six sites where mobile sound measurement equipment were positioned in coordination with DAAC District Council memberships. A map of all St. Paul Districts is provided in Appendix A.3. The mobile sound measurement sites were positioned in the same or similar locations each year as much as possible to assist with comparing results. Figure 3.1 shows a map of the historical mobile equipment placement locations from previous studies for reference. The 2024 STP Annual Sound Study period is August 13-19, 2024. As determined by the DAAC in April 2023, data collection for this study did not include physical placement of mobile measurement equipment as used in previous STP sound studies. The 2024 Study only utilizes the federal process and AEDT software for the assessment of aircraft activity and sound levels. Specifically, STP aircraft activity during the study period was modeled using AEDT, Version 3g. Study period inputs to AEDT include types of aircraft operating, weather conditions, runway use as well as local terrain information. Based on aircraft types, AEDT makes assumptions about aircraft performance, flap configurations, engine settings, and weight. AEDT uses standard aircraft thrust settings, standard departure climb-rates as well as standard arrival descent rates, which may not represent actual flight operating characteristics. Additionally, certificated sound data are available for many aircraft types in the model, however all aircraft operating at STP are not available in the software. In those situations, modeling requires aircraft substitutions be used to represent missing aircraft types. The AEDT model can produce various sounds metrics. Two metric options available are the Number Above Noise Level and Time Above Noise Level. For this analysis, MAC staff evaluated the number of operations at or above 65 dBA at a specific grid point and their duration. This modeled sound analysis depicts aircraft sound events from actual aircraft activity at STP from August 13, 2024 through August 19, 2024 using model inputs such as runway use, aircraft fleet mix, aircraft performance and thrust settings, topography, and atmospheric conditions. The study utilized MACNOMS fleet and runway use information. MACNOMS aircraft operations counts were adjusted up to equal the 1,007 operations reported by the FAA during the study period. Quantifying aircraft-specific sound characteristics in AEDT is accomplished using a comprehensive database developed by the FAA under 14 CFR Part 36. As part of the airworthiness certification process, aircraft manufacturers are required to subject aircraft to extensive sound testing. Using federally-adopted and endorsed algorithms, this aircraft-specific sound information is used in the generation of model outputs. Justification for such an approach is rooted in national standardization of sound quantification at airports. Appendix A.1 includes the fleet mix and Appendix A.2 includes weather data utilized in the AEDT model for this analysis. AEDT uses a grid pattern of individual sound measurement points, known as receptors, and calculates sound at each of these points. The grid pattern for this study included 22,500 unique points spaced 0.1 nautical miles apart for a range of 15 miles. 8 Figure 3.1: Measurement Locations Used in Previous Studies* *Note: Field locations were not used to collect sound measurements during the 2024 STP Annual Sound Study assessment. Instead, the federally-approved AEDT noise model was used to assess noise across 22,500 receptor points. 9 Additionally, AEDT uses standard weather inputs that are typically available for a study comprising a full year of data. For this study, standard weather inputs were changed to represent the average weather conditions for the seven-day study period. These inputs are available in Appendix A.2. Figure 3.2 shows the modeled grid points by average number of events per day during the study period. Grid points with the highest number of events per day are located within STP airport property. Table 3.1 below provides the total number of aircraft sound events above 65 dBA modeled at each historic field measurement location. The table also provides the number of modeled sounds events above 65 dBA correlated to aircraft that were previously modeled during other study periods for comparison. Table 3.1 Modeled Number Above 65 dBA Sound Levels Site 2020 2021 2022 2023 2024 1 13 22 100 64 22 2 88 67 134 131 109 3 70 48 77 79 97 4 32 25 59 53 18 5 92 121 107 97 70 6 62 147 117 100 91 Table 3.2 below provides the total amount of time aircraft sound levels were above 65 dBA modeled to occur at each historic measurement locations. The table also provides the total modeled time above 65 dBA correlated to aircraft modeled during other study periods for comparison. Table 3.2 Modeled Time Above 65 dBA Sound Levels (min) Site 2020 2021 2022 2023 2024 1 1.8 2.3 10.0 6.0 3.8 2 18.6 8.8 19.2 21.0 24.2 3 22.7 9.8 16.9 19.4 19.4 4 6.5 4.8 10.9 7.6 5.5 5 19.3 24.7 24.7 21.1 14.1 6 14.7 34.3 25.1 23.5 20.4 Figure 3.3 shows the modeled grid points by average time spent above 65 dBA per day during the study period. 10 Figure 3.2: Number of Events Above 65 dBA per Day 11 Figure 3.3: Time Above 65 dBA (minutes per day) 12 4.0 Noise Complaints During the 2024 study period, two complaints were received from two Saint Paul households, and six complaints were received from four households in other cities. Two complaints were received during nighttime hours, between 10:00 P.M. and 7:00 A.M. Table 4.1 illustrates the complaints with correlated operations by aircraft type. Piston aircraft operated the most flights during the study period. Jet aircraft generated the greatest number of complaints. Table 4.1 2024 Study Period Complaints and Operations Aircraft Type Operations Complaints Helicopter 133 4 Commercial Jet 10 1 Jet 255 2 Piston 405 1 Turboprop 110 - Unknown 8 - Total 919 8 Figure 4.1 shows a complaint heat map representing the number of households that submitted a complaint within each grid square for areas near STP airport. Figure 4.2 shows complaints and the number of events above 65 dBA for all areas during the study period. 24 Figure 4.1: STP Study Period Complaint Heat Map* *Complaint locations outside of the City of Saint Paul not shown. 25 Figure 4.2: STP Study Period Complaint Heat Map with Number of Events Above 65 dBA 26 Appendix A.1 Modeled Aircraft Distribution Aircraft Type Arrival Departure Touch & Go Total Day Night Day Night Day Night Beechcraft Bonanza 35 (FAS) 3 - 1 1 - - 5 Bell 407 / Rolls-Royce 250-C47B 6 5 6 4 - - 20.9 Bombardier Challenger 300 7 - 5 1 - - 12.9 Bombardier Challenger 350 3 - 3 - - - 6 Bombardier Challenger 601 3 1 3 - - - 7 Bombardier CRJ-100 3 - 3 - - - 6 Bombardier Global 6000 1 - 1 - - - 2 Bombardier Learjet 31 2 - 2 - - - 4 Bombardier Learjet 35 1 - 1 - - - 2 Bombardier Learjet 45 1 - 1 - - - 2 Bombardier Learjet 55 1 - - - - - 1 Bombardier Learjet 60 2 - 2 - - - 4 Cessna 150 Series 5 - 6 - 29.9 - 40.8 Cessna 152 (FAS) 3 - 3 - 13.9 - 19.9 Cessna 172 Skyhawk 18.9 1 16.9 1 89.6 - 127.4 Cessna 177 (FAS) 1 - 1 - - - 2 Cessna 180 (FAS) 2 - 5 - - - 7 Cessna 182 1 - 1 - - - 2 Cessna 182 R (FAS) 1 - - 1 - - 2 Cessna 206 1 - 1 - - - 2 Cessna 414 1 - 1 - - - 2 Cessna 441 Conquest II 2 - 2 - - - 4 Cessna 550 Citation II 1 - 1 - - - 2 Cessna 560 Citation Encore - - 0.6 - - - 0.6 Cessna 560 Citation Ultra - - 0.4 - - - 0.4 Cessna 560 Citation XLS 11.9 1 10 3 - - 25.9 Cessna 650 Citation III 1 - 1 - - - 2 Cessna 680 Citation Sovereign 11 2 12.9 3 - - 28.9 Cessna 700 Citation Longitude 7 - 8 - - - 14.9 CESSNA CITATION 510 1 - 2 - - - 3 Cessna CitationJet CJ2 (Cessna 525A) 2 - 2 - - - 4 Cessna CitationJet CJ3 (Cessna 525B) 2 - 2 - - - 4 Cessna CitationJet CJ4 (Cessna 525C) 1 - 1 - - - 2 Cirrus SR20 5 2 6 1 25.9 - 39.8 Cirrus SR22 Turbo (FAS) 6 - 4 - - - 10 Cirrus Vision SF50 (FAS) 2 - 2 - - - 4 Dassault Falcon 2000 14.9 - 12.9 - - - 27.9 27 Aircraft Type Arrival Departure Touch & Go Total Day Night Day Night Day Night Dassault Falcon 50 2 - 1 1 - - 4 Dassault Falcon 900 1 - 1 - - - 2 EADS Socata TBM-700 2 - 1.5 - - - 3.5 Embraer Legacy 500 (EMB-550) 2 - - - - - 2 Embraer Phenom 100 (EMB-500) 9 - 5 2 - - 15.9 Eurocopter EC-155B1 2 - 2 - - - 4 Falcon 7X 3 - 2 - - - 5 Gulfstream G150 - - 1 - - - 1 Gulfstream G280 - - 1 - - - 1 Gulfstream G400 4 - 4 1 - - 9 Gulfstream G500 4 - 4 - - - 8 Gulfstream II 3 - 4 - - - 7 Mooney M20-K 2 - 3 - - - 5 Pilatus PC-12 4 3 5 2 - - 13.9 Piper PA-28 Cherokee Series 10 1 9.5 - 25.9 - 46.3 Piper PA-30 Twin Comanche 1 - 1 - - - 2 Piper PA-32 Cherokee Six 3 1 3 - - - 7 Piper PA-34 Seneca 2 - 2 - - - 4 Piper PA46 Malibu (FAS) 1 1 1 - - - 3 Piper PA46-TP Meridian 1 - 1 - - - 2 Raytheon Beech Baron 58 1 - 1 - - - 2 Raytheon Beech Bonanza 36 5 - 4 - - - 9 Raytheon Beechjet 400 7 - 6 1 - - 13.9 Raytheon Hawker 800 7 - 6 1 - - 13.9 Raytheon King Air 90 4 - 3 1 - - 8 Raytheon Super King Air 200 17.9 6 16.9 5 - - 45.8 Raytheon Super King Air 300 1 - 1 - - - 2 Robinson R44 Raven / Lycoming O-540-F1B5 22.9 - 22.9 - - - 45.8 Socata TBM-9 (FAS) - - 1 - - - 1 Vans RV12 (FAS) 1 - 1 - - - 2 Grand Total 256.9 23.9 244.9 28.9 185.2 - 739.8 Source: MACNOMS data and HNTB Analysis, 2024. Totals are subject to rounding offsets. 28 A.2 STP Weather Details Source: Mesonet Iowa State 2024 Model Weather Inputs Average Temp 70.4 Average Wind Speed 7.6 Average Dew Point 60.3 Average Sea Level Pressure (SLP) 29.2 Average Relative Humidity 72.9 Average SLP (millibar) 989.8 29 A.3 St. Paul District Council Map and Details Source: www.stpaul.gov/residents/live-saint-paul/neighborhoods/district-councils/district-council-directory 30 A.4 Supplemental Conditions of Agreement 31 32 33 A.5 Glossary Aircraft Operation Aircraft arriving or departing from STP, or an aircraft that performed both an arrival and departure (touch and go). Air Traffic Control (ATC) Air Traffic Control (ATC) is an FAA service that direct aircraft on the ground and through a given section of controlled airspace and can provide advisory services to aircraft in non-controlled airspace. Aviation Environmental Design Tool (AEDT) modeling software The Aviation Environmental Design Tool (AEDT) is a software system that models aircraft performance in space and time to estimate fuel consumption, emissions, noise, and air quality consequences. A-Weighting A-Weighting is a standard filter used by acoustic measurement devices and can be applied to acoustic measurements. It is frequency filter that attempts to emulate the way human hear. Day-Night Level (DNL) The FAA established DNL as the primary metric for aircraft noise analysis and expressing aircraft noise exposure in the United States. "DNL" is the acronym for Day-Night Average Sound Level, which represents the total accumulation of all sound energy, with a 10-decibel penalty applied for each sound event between 10:00 P.M. and 7:00 A.M. DNL has been widely accepted as the best available method to describe aircraft noise exposure and is the industry standard for use in aircraft noise exposure analyses and noise compatibility planning. It also has been identified by the U.S. Environmental Protection Agency as the principal metric for airport noise analyses. Decibel (dB/dBA) Sound levels are measured in Decibels, a logarithmic scale of energy referenced to human hearing. Sound levels are reported in dB; dBA is the Decibel value after the A-Weighting filter is applied. Federal Aviation Administration’s (FAA) The Federal Aviation Administration (FAA) is federal agency with the sole regulatory authority over aviation in the United States, including airports, pilots, airspace, flight procedures, and aircraft. LA max (Maximum A-weighted Sound Level) This is maximum A-Weighted Sound Level observed for the period, event, or interval of interest. 34 Metropolitan Airports Commission (MAC) The Metropolitan Airports Commission (MAC) is the airport authority that owns and operates the Minneapolis-St. Paul International Airport (MSP) and six general aviation airports in the Twin Cities region. MACNOMS™ (MAC Noise and Operations Monitoring System) MAC Noise and Operations Monitoring System (MACNOMS) includes data collection, data processing, data analysis and publication, and community tools for accessing data. The MACNOMS data collection, processing and analysis and reporting tools are made up of customized software programs and instruments that provide system flexibility to conduct detailed analyses and reporting of aircraft operations and associated noise collects and reports flight track, sound and complaint data. Minneapolis-St. Paul International Airport (MSP) The Minneapolis-St. Paul International Airport (MSP), also less commonly known as Wold-Chamberlain Field, is a joint civil-military public-use international airport located in Fort Snelling Unorganized Territory, Minnesota, United States. Number Above The "Number Above", also referred to as N-level sound metric or Count Above, is the total number of aircraft sound events that exceeded a specified sound level threshold (LA max). This report contains a count of modeled departure events and arrival events when the maximum sound level of those events exceeds 65 dBA. Saint Paul Downtown Airport - Holman Field (STP) The Saint Paul Downtown Airport - Holman Field, is a public airport in the City of Saint Paul, County of Ramsey, State of Minnesota. Saint Paul Downtown Airport Advisory Council (DAAC) The DAAC was established to further the general welfare of the community and the Saint Paul Downtown Airport - Holman Field through minimizing or resolving problems created by the operation of the airport and aircraft. is comprised of appointed STP airport users and community representatives who reside in the Districts surrounding STP. Time Above The "Time Above" noise metric measures the total time or percentage of time that the A-weighted aircraft noise level exceeds an indicated level. Time Above data are summarized for arrival and departure events based on one-second intervals. Metropolitan Airports Commission 6040 28th Avenue South, Minneapolis, MN 55450 MetroAirports.org This report is for informational purposes only.