Background to Part 150 Studies
The Part 150 establishes a voluntary, Federal Aviation Administration (FAA) administered program that includes procedures to be followed by airports to assess aircraft noise and land use compatibility. It establishes a single system for the measurement of aircraft (and background) noise, a single system for determining the exposure of individuals to aircraft noise, and a standardized airport noise compatibility planning program. The planning program includes: (1) provisions for the development and submission to the FAA of a Noise Exposure Map and Noise Compatibility Program by airport operators; (2) standard noise units, methods, and analytical techniques for use in airport assessments; (3) identification of land uses which are normally considered compatible (or non-compatible) with various levels of noise around airports based on federal thresholds; and (4) procedures and criteria for FAA approval and disapproval of noise compatibility programs. The Noise Compatibility Program will contain recommendations for noise abatement and mitigation addressing both land use and aircraft operational issues.
The Part 150 Compatibility Study Update that is currently underway will update the existing noise exposure maps by looking at current noise and land use conditions and develop a forecast of future conditions, as well as meet the requirements of the use agreement between the Airport and the Department of the Interior.
The objective of this Part 150 Noise Compatibility Study Update is to update the Noise Exposure Maps based on current and forecast future conditions and find reasonable solutions to the problems associated with noise generated by aircraft, and to present solutions that can be implemented through update of the Noise Compatibility Program (NCP). The goal of the overall program is for the Jackson Hole Airport, in consultation with the National Park Service, state/local planners, local aviation groups, and interested citizens, to develop a balanced and cost-effective program to minimize and/or mitigate aircraft noise effects on Grand Teton National Park and surrounding land uses.
Work on the Part 150 Noise Compatibility Study Update started in May 2014. Completion is anticipated in late 2015 to early 2016. The Schedule page on this website will have additional information on the generalized schedule process and the Welcome page will include updates as available. Once the Noise Exposure Maps (NEMs) are accepted by the Federal Aviation Administration (FAA), it will take up to an additional six months for FAA approval.
Because the Airport is located within Grand Teton National Park, it operates under a use agreement with the Department of the Interior. One of the requirements of the use agreement with the Department of the Interior is to “further reduce noise and other negative environmental impacts associated with the Airport,” and use the latest in noise mitigation technology and procedures. These are best addressed through the completion of a Part 150 Study. The Jackson Hole Airport is updating their previous Part 150 Noise Compatibility Study because the Federal Aviation Administration (FAA) requires that the Airport have current Noise Exposure Maps to receive federal funding for noise mitigation measures. The existing Noise Exposure Maps were last completed in 2003 and since then there have been changes to aircraft fleet mix, change in aircraft activity levels, and updates to the noise model used for analysis, which will all be considered during the Study Update.
In 1981, the Federal Aviation Administration (FAA) formally adopted the Day Night Average Sound Level (DNL) as the primary measure for determining exposure of individuals to airport noise. Day Night Average Sound Level is the annual, 24-hour average sound level, in decibels, obtained from the accumulation of all noise events, with the addition of 10 decibels to weighed sound levels from 10 P.M. to 7 A.M. The weighing of nighttime events accounts for the fact that noise events at night are more intrusive when ambient levels are lower and people are trying to sleep. The 24-hour DNL is annualized to reflect noise generated by aircraft operations for an entire year and is identified by “noise contours” showing levels of aircraft noise.
DNL is the most widely accepted descriptor for aviation noise because of the following characteristics: DNL is a measurable quantity; DNL can be used by airport planners and the general public who are not familiar with acoustics or acoustical theory; DNL provides a simple method to compare the effectiveness of alternative airport scenarios; and DNL is based on a substantial body of scientific survey data regarding the reactions people have to noise.
Noise contours are computer generated lines that are modeled to reflect both current noise conditions near airports as well as to predict what the future noise conditions will be. Technically, a noise contour represents the average annual noise levels (Day Night Average Sound Level, or DNL) summarized by lines connecting points of equal noise exposure.
The Part 150 Noise Study normally uses the 65 DNL contour to represent non-compatible land uses and determine eligibility for federal funds for noise mitigation. Any noise sensitive uses (such as residences, schools, churches, etc.) within the 65 DNL and greater contour are considered to be non-compatible with aircraft noise. Therefore, noise sensitive uses within this contour could be eligible for federal funding for noise mitigation measures that will be analyzed in the Part 150 Study Update.
This Part 150 Study is unique due to the location of the Airport within Grand Teton National Park. Because of its location within this particularly noise-sensitive area, this Part 150 Study will incorporate special noise thresholds and criteria for determining noise effects in the park that have been agreed upon by the Airport and Department of the Interior. For this reason, the Study will analyze DNL noise levels at the 60, 55, 50 and 45 DNL in addition to the 65 DNL.
A variety of information is gathered during the Study to create an accurate noise contour including: the number of flights, flight paths, type of aircraft, type of aircraft engines, time of day, weather conditions, and runway use. Actual on-site noise measurements specific to aircraft operating at Jackson Hole Airport will be used to verify predicted individual aircraft noise levels contained in the computer model.
These data are used to generate noise contours that are overlaid onto base maps to create a Noise Exposure Map (NEM), which is used to identify where specific levels of aircraft noise occur. The Noise Exposure Maps developed for Jackson Hole Airport will be used in several ways:
- Defining where areas of roughly equal noise exist in the communities surrounding the Airport
- Assessing noise levels relative to the specific noise criteria for Grand Teton National Park
- Assessing various alternative solutions to reduce the effect of noise
- Defining eligibility for federal funds for noise abatement programs
The Integrated Noise Model (INM) is the model developed by the Federal Aviation Administration (FAA) for evaluating aircraft noise impacts in the communities surrounding airports. The INM uses inputs such as number of operations, aircraft fleet mix (aircraft types), aircraft flight tracks, and flight profiles, time of day of operations and terrain to evaluate aircraft noise. The INM has been used by the FAA since 1978, but has been updated many times since then to include improved metrics and the most current aircraft information. The INM is the model required by the FAA to create the noise contours for use in Part 150 Studies.
Sometimes the Day Night Average Sound Level (DNL) metric used in Part 150 Studies is criticized because it averages noise over a 24-hour period for an entire year, which can seem to downplay noise events that can have large effects on residential populations and does not accurately portray what people actually hear on a day to day basis. It is true that because the Integrated Noise Model represents noise in an annual average, it does not represent what people hear when an aircraft flies over. This Study will present data with single event metrics, which helps to illustrate what people hear with a flyover. These single event metrics are being conducted as part of this Study primarily for informational purposes because based on Federal Aviation Administration (FAA) regulation, the DNL metric is required to be used in the Part 150 analysis. The noise mitigation measures within this Study are approved or disapproved based on this metric.
However, because of the unique location of the Jackson Hole Airport within Grand Teton National Park, this noise study takes into account additional considerations based on the use agreement between the Department of the Interior and the Airport. This includes consideration of the 45 DNL noise contour (to consider effects on potential areas of natural quiet) and consideration of single event maximums of 92 A-weighted decibels on approach.
While DNL is the primary designator for noise effects, other metrics such as Time Above Ambient, Number of Events Above Ambient, and Time Audible are also examined for informational purposes
The Part 150 Noise Study uses the 65 DNL and greater contour to represent non-compatible land uses and determine eligibility for federal funds for noise mitigation. Any noise sensitive uses (such as residences, transient lodgings, schools, hospitals, nursing homes, churches, auditoriums, concert halls, and outdoor music shells and amphitheaters) within the 65 Day Night Average Sound Level (DNL) and greater contour are considered to be non-compatible with aircraft noise. Therefore, noise sensitive uses within this contour could be eligible for federal funding for noise mitigation measures. These measures and potential eligibility will be analyzed in the Part 150 Study Update.
In addition, based on the tenets of the use agreement, some areas of Grand Teton National Park that have been determined to be highly noise sensitive are considered non-compatible with 45 DNL and greater noise levels. There is also a single event limit of 92 A-weighted decibels on approach.
The future noise contours will include all projects that are either completed or in the Capital Improvements Program to be completed by 2020 and have environmental approvals. Therefore, at this time, there are no additional known physical projects that would be included that could alter the baseline noise conditions.
The Study includes aircraft in the air that operate from Jackson Hole Airport, aircraft on the ground and aircraft-related point sources, such as auxiliary power units (APUs) and ground power units (GPUs). The Study must follow federal regulations and therefore, it does not include sources such as ground support equipment, airfield equipment (such as snow plows), cars, or other non-aviation related noise sources.
Flight tracks will be examined as part of the Study. NextGen procedures (procedures that involve satellite-based navigation), may allow for more precise procedures to be flown into and out of JAC, potentially enhancing aircrafts’ ability to more easily avoid overflying noise-sensitive uses. Additionally, while the Study may make recommendations on flight track changes, only the Federal Aviation Administration (FAA) can decide whether or not to implement them based on a number of factors, including safety.
The Study Input Committee will be comprised of a wide variety of stakeholders representing the Airport, Grand Teton National Park, the FAA, and other agencies, as well as members of the public, airport tenants and airline representatives.
The Airport, Federal Aviation Administration (FAA), National Park Service/Department of the Interior, stakeholders, and the public all have the opportunity to be involved in the Part 150 Study Update process. A Study Input Committee (SIC) will be formed to work closely with airport staff and the consultant team of Mead & Hunt. The Study Input Committee includes members representing aviation, the National Park Service, business, and citizen interests. The role of the Committee is to review information, provide feedback, discuss noise abatement alternatives, and advise the Airport on the adoption of a noise abatement program at the airport. Additionally, public information meetings/workshops will be held at key points throughout the Study. These meetings will be announced on this website and will be advertised in the local newspaper.
This Part 150 Study is unique because of the location of the Airport within Grand Teton National Park. National Parks are considered to be noise sensitive and fragile, and are protected from excessive noise disturbances. Because of the Airport’s location within this particularly noise-sensitive area, this Part 150 Study will incorporate special noise guidelines and criteria for determining noise effects in the park. Some areas of the park have a lower allowable noise threshold than the typically-used 65 DNL noise level. A boundary line has been established in the park beyond which the areas are considered non-compatible with 45 DNL or greater noise levels. Therefore, the Study will analyze DNL noise levels at the 60, 55, 50 and 45 DNL in addition to the 65 DNL. There is also a single event limit of 92 A-weighted decibels on approach.
The Federal Aviation Administration (FAA) is the federal agency for Part 150 Studies. This Part 150 Study is unique in that a second federal agency, in this case the National Park Service (NPS), will have a large role in the Study process in addition to the FAA. This is due to the Airport being located within Grand Teton National Park, which is managed by the NPS.
The National Park Service (NPS) will play an integral role in this Part 150 Study. The NPS has historically worked closely with Jackson Hole Airport and the Federal Aviation Administration to assess noise effects to Grand Teton National Park, which surrounds the Airport; determine special noise level criteria for the park based on the sensitivity of wildlife, ecosystems, and the purposes of the park; and implement measures to reduce noise effects. The NPS will participate in all aspects of the Study and will have representation on the Study Input Committee established to guide the Part 150 Study.
NPS/Department of the Interior input and agreement on the Study is crucial, as the Airport Board and the Department of the Interior entered into an ongoing agreement in 1983 for control of Airport noise effects on the park. An amendment to the agreement occurred in May 2011 stipulating that the Airport Board “shall seek to further reduce noise and other negative environmental impacts associated with the Airport.” Several of the requirements of the amendment will be addressed through this Part 150 Study.
Public Information Meetings/Workshops will be held at key times during the Study process. These meetings will be a mix of presentations and “open house” style of the meetings that will allow you to view maps showing the level of noise exposure at various locations, flight tracks of aircraft, and other aircraft activity at Jackson Hole Airport. Various alternatives will be presented and draft recommendations will be available for review. You will have the opportunity to ask questions and express your concerns and comments. Meeting dates will be advertised in local papers and posted on this website.
All comments submitted will be taken into consideration during this Study. However, each individual comment provided throughout the process will not be responded to; rather, the most frequently asked questions will be addressed generally in these Frequently Asked Questions on the website.
This project will use the Federal Aviation Administration’s Integrated Noise Model (INM) Version 7.0d. The INM is the model developed by the FAA for evaluating aircraft noise impacts in the communities surrounding airports. The INM uses inputs such as number of operations, aircraft fleet mix (aircraft types), aircraft flight tracks, and flight profiles, time of day of operations and terrain to evaluate aircraft noise. The INM has been used by the FAA since 1978, but has been updated many times since then to include improved metrics and the most current aircraft information.
Standard Integrated Noise Model (INM) inputs use flight distance stage lengths to assign the departure profiles. Changes to the airline industry, including higher aircraft load factors, have had an effect on how aircraft fly. Higher load factors result in heavier aircraft flying on shorter haul routes that were traditionally operated with much lower load factors. The consultant producing the noise contours will use actual radar climb profile data to assign the most appropriate standard stage length to each flight. The flight profiles used in this FAR Part 150 Study Update are not custom, rather a more appropriate use of the standard Stage 1 – 9 INM-defined stages based upon the actual profile flown. The consultant generating the noise contours has determined from previous studies and noise modeling work at JAC that this produces a more accurate picture of how aircraft actually operate at the airport.
The airport operates a noise monitoring system that includes six permanent noise monitoring sites in the community and the park; the monitors operate 24 hours per day, 7 days a week. While not specifically required by FAR Part 150, measurements are often very helpful in showing actual noise levels and validating the computer based modeling. The noise measurement survey is an integral part of this Study. Information regarding noise levels from this system and the additional temporary noise monitoring stations can be found in Chapters C, D and E of the draft FAR Part 150 Study Update.
Due to the sensitivity of the Park’s natural quiet and wildlife as well as to protect the ability of visitors to enjoy the park, the NPS has established a restriction line within the park beyond which aircraft noise levels cannot exceed 45 DNL. This 45 DNL limit is also known as the Critical Area Boundary and is illustrated in Figure A7 of the draft FAR Part 150 Study Update.
The members of the Study Input Committee were appointed at the project kick-off in June 2014. Members include airport staff, consultant staff, community members, FAA, operators, airline representatives, and industry stakeholders.
Operations by helicopters accounted for less than 100 operations for the base year of the Study; there are currently no scheduled sightseeing helicopter operators at JAC.
The FAA Integrated Noise Model is widely used by the civilian aviation community for evaluating aircraft noise impacts in the vicinity of airports. The model is typically used in the U.S. for Part 150 noise compatibility planning, Part 161 approval of airport noise restrictions, and for environmental assessments and environmental impact statements under the current version of FAA Order 1050.1E. The FAA does not specifically state an accuracy level. However, the core calculation modules of INM are based on standards documents produced by the Society of Automotive Engineers (SAE) Aviation Noise Committee (A-21). This internationally represented committee is composed of research institutions, engineering firms, aircraft and engine manufacturers, government regulatory agencies, and end-users of noise modeling tools. The INM’s core computation modules are also compliant with other international standards documents including European Civil Aviation Conference (ECAC) Document 29 and International Civil Aviation Organization (ICAO) Circular 205.
INM is designed to estimate long-term average effects using average annual input conditions. Because INM is not a detailed acoustics model, differences between predicted and measured values can and do sometimes occur because important local acoustical variables are not averaged, or because complicated physical phenomena are not explicitly modeled. INM aircraft flight profile and noise calculation algorithms are based on the methodology presented in the SAE-AIR-1845 report. In the U.S., annual day-night average sound level (DNL or Ldn) is used for quantifying airport noise. The Part 150 definition of this quantity is: Yearly day-night average sound level (Part 150 Sec. A150.205(c)): “(YDNL) means the 365-day average, in decibels, day-night average sound level. The symbol for YDNL is also Ldn. It is computed in accordance with the following formula: Ldn = 10 log( (1/365) Σ 10 Ldni/10 ) where Ldni is the day-night average sound level for the i-th day out of the year.” The summation is from i = 1 to 365. If you were to use this definition to model noise in INM, you would have to run 365 cases of the model and average the results. Instead, INM uses the concept of an “average annual day”. Part 150 allows the use of average input data in INM, as follows: Operational data (Part 150 Sec. A150.103(b)): “…the following information must be obtained for input to the calculation of noise exposure contours: … (2) Airport activity and operational data which will indicate, on an annual average-daily-basis, the number of aircraft, by type of aircraft, which utilize each flight track, in both standard daytime (0700-2200 hours local) and nighttime (2200-0700 hours local) periods for both landings and takeoffs.” An average annual day is a user-defined best representation of the typical long-term average conditions for the airport. These average conditions include the number and type of operations, routing structure, runway configuration, aircraft weight, temperature, and wind.