2020 Annual
Noise Report
May 2022
Prepared For:
Jackson Hole Airport Board
Jackson Hole Airport
1250 East Airport Road
Jackson, Wyoming 83001
Prepared By:
20201 SW Birch Street Suite 150
Newport Beach, CA 92660
Table of Contents
Jackson Hole Airport BridgeNet International
2020 Annual Report
i
Table of Contents
1.0 Introduction 1-1
2.0 Background Information on Noise 2-1
2.1 Background 2-1
2.2 Noise Metrics 2-4
2.3 Noise Assessment Guidelines 2-5
2.4 Methodology in Determining the Noise Environment 2-6
3.0 Operational and Flight Data 3-1
3.1 Aircraft Operations 3-1
3.2 Enplaned Passengers
3.3 Measurement and Analysis Procedures 3-4
Continuous Measurement of the Noise 3-4
3.4 Aircraft Operational and Radar Track Data 3-4
Correlation of Noise and Flight Data 3-5
Calculation of Aircraft Noise Metrics 3-5
4.0 Noise Measurement Results 4-1
4.1 Introduction 4-2
4.2 Continuous Noise Measurement Data 4-2
4.3 Ambient Noise Measurement Results 4-4
4.4 Aircraft Single Event Noise Measurement Results 4-7
4.5 DNL Noise Measurement Results 4-11
5.0 Annual Noise Contours
5.1 Introduction 5-1
5.2 Existing Aircraft Operations 5-2
Fleet Mix 5-3
Time of Day 5-3
Runway Use 5-3
Flight Path Utilization 5-6
5.3 Modeling Results 5-9
6.0 Summary 6-1
6.1 Overall Summary
Table of Contents
Jackson Hole Airport BridgeNet International
2020 Annual Report
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List of Tables
Table 1-1 Noise Measurement Sites 1-2
Table 3-1 Annual Operations and Enplaned Passengers 3-2
Table 3-2 Comparison of Average Daily Operations for Seasons 2014 and 2015 3-3
Table 4-1 Ambient Noise Measurement Results 4-5
Table 4-2 Aircraft DNL Noise Measurement Results 4-15
Table 5-1 Summary of Operations 5-2
Table of Contents
Jackson Hole Airport BridgeNet International
2020 Annual Report
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List of Figures
Figure 1-1 Noise Measurement Location Map 1-3
Figure 2-2 Noise Sensitive and Critical Area Boundary 2-2
Figure 3-1 Month to Month Operations for 2020 3-3
Figure 4-1 Sample Time History Noise Plot of Aircraft and Ambient Noise 4-3
Figure 4-2 Site Specific Ambient Noise Measurement Results 4-6
Figure 4-3 Noise Event Summary and Histogram Report, Moose and 4LAZYF 4-8
Figure 4-4 Noise Event Summary and Histogram Report, Moutlon and Golf 4-9
Figure 4-5 Range of Noise and Number of Events Histograms 4-10
Figure 5-1 Arrival and Departure Tracks for Runway 19 5-4
Figure 5-2 Arrival and Departure Tracks for Runway 01 5-5
Figure 5-3 2020 Annual DNL Noise Contours 5-7
Section 1 Introduction
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 1-1
1.0 Introduction
The purpose of this report is to present the results from the 2020 noise measurement and modeling
survey at Jackson Hole Airport. Noise measurements are conducted year around to determine the
annual noise exposure levels from the airport. Periods during the peak winter and peak summer
seasons are also presented in order to illustrate the peak activity during each season. This year-end
report summarizes the results from the peak winter and peak summer noise periods as well as the
annual measurements for 2020. These results are compared and summarized with respect to the
noise limits established at the airport. The results are also compared to previous noise
measurements conducted since 1984, presenting the changes in noise levels at the airport that have
occurred over time.
Historically from 1984 to 2003, noise monitored was conducted using portable noise monitors for
seasonal periods at three locations around the airport. Each site was monitored for one to three
weeks during both the winter and summer peak season. The three sites that were monitored
historically were Moulton Loop south of the Airport, Moose, and Barker Ranch in Grand Teton
National Park (GTNP). In 2003, Jackson Hole Airport installed six (6) permanent noise monitors
to collect noise data continuously year around. Moulton Loop, Moose, and Barker Ranch were
converted to permanent monitoring sites as part of this upgrade. These measurement locations at
these three sites and the three additional sites are presented in Table 1-1 and Figure 1-1.
In 2014 radar data collection system was installed that allowed the noise system to store flight
track information. Prior to that, it was not possible to always identify a noise event to the aircraft
that caused the event. It was a manual process based upon the flight logs. The initial annual
reports were based upon seasonal noise monitoring. The radar data during this time period did not
have radar coverage at lower altitudes near the airport. Often the aircraft was not tracked until it
reached 10,000 feet MSL. In 2020 the FAA’s ADS-B surveillance became fully operational and
the airport installed a local ground station that now provides radar coverage at areas close to the
airport.
The historical annual reports provided information on the season measurement results for the
period measured. With the installation of the permanent system, the reports still presented seasonal
data to continue to show the peak period activities in summer and winter. The reports since the
radar data was captured also provided the annual results. Starting in this 2020 report, the report
format will be refreshed to provide show both seasonal and annual data with the focus on the
annual results. The report also presents calendar year results, and no split year based upon full
seasons (October through September).
Section 1 Introduction
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Table 1-1
Noise Measurement Sites
Sites
Name
Location
Area
Longitude
1
Moulton Loop
Zenith Drive and Spring Gulch
Road
South
Residential
-110.744542
2
Golf Course
Jackson Hole Golf & Tennis
Club
South
Residential
-110.753580
3
Barker Ranch
Circle H Ranch (Former
Barker’s Residence)
GTNP
-110.758610
4
Moose
Moose along Snake River
GTNP
-110.716753
5
4 Lazy F Ranch
4 Lazy F Ranch
GTNP
-110.708956
6
Timber Island
East of Timber Island
GTNP
-110.713525
Source: BridgeNet International, 2022
One of the purposes of the measurements is to determine if the airport is in compliance with the
Agreement between the U.S. Department of the Interior and the Jackson Hole Airport Board
(Agent). The results of the measurements show that the airport is in compliance with the
requirements of the Airport Use Agreement. Aircraft noise levels within the Park are measured to
be below the levels specified within the Use Agreement with the Department of the Interior. In
addition, the FAA has established a guideline of 65 DNL as the goal for compatibility with
residential land use. The 65 DNL noise levels does not extend into residential land uses.
Section 1 Introduction
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Figure 1-1
Noise Measurement Location Map
Source: BridgeNet International, 2022
Section 2 Background Information on Noise
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2.0 Background and Information on Noise
2.1 Background
Jackson Hole Airport is the only commercial service airport in the country that is located
entirely within a National Park. Accordingly, it has had a long history of addressing noise and
operates under a number of special restrictions. The Airport Board itself has also developed a
number of special noise abatement measures to minimize impacts from aircraft noise. These
measures and a brief history of their development are presented in this section.
In 1983 the Airport Board and the Department of the Interior entered into a new agreement for
the continued operation of the Airport in Grand Teton National Park, subject to noise
restrictions. The primary restrictions are that the Airport cannot exceed specific Day-Night
Level (DNL) cumulative noise levels at critical locations within the Park boundary. The annual
cumulative level from aircraft noise at the Moose measurement location cannot exceed 55 DNL.
In addition, there is a Critical Area Boundary within the Park where annual aircraft noise levels
cannot exceed 45 DNL. The 45 DNL Critical Area Boundary line is presented in Figure 2-1.
In order to meet the cumulative noise limits of the Agreement, the Airport Board developed an
Airline Access Plan. This Access Plan places a limit on the number of operations of commercial
jet aircraft which are necessary to meet the cumulative standards. Operations of the 737-
200/D17 “base class” aircraft were limited to 6.5 Average Daily Departures. Increases in the
number of operations may only be accomplished by substituting quieter, new generation of
aircraft, which at that time were just entering service.
Section 2 Background Information on Noise
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Figure 2-1
Noise Sensitive and Critical Area Boundary
Source: BridgeNet International, 2022
Section 2 Background Information on Noise
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The Agreement also included a single event noise limit which restricted the operation of any
aircraft that generated sound levels above 92 dBA, as defined by the approach dBA level from
FAR 36 regulations (Note: this numeric value should not be compared to noise levels shown in
this report in that the measurements utilized a different noise metric, and at particular locations
in relation to the Airport). This essentially eliminated aircraft from operating at the Airport
that generated higher noise levels than the Boeing 737-200/D17 aircraft.
The Agreement also required that a revised noise control plan be developed which “... utilizes
the latest in noise mitigation technology and procedures. The revised plan will be developed
in a comprehensive study to consider all of the relevant environmental, economic, and
operational considerations.” The primary objectives of the noise control plan as stated in the
Agreement were “to ensure that future airport operations are controlled in such a manner that
aircraft noise exposure will remain compatible with the purposes of Grand Teton National Park
and will result in no significant increase in cumulative or single event noise impacts on noise
sensitive areas of the Park.”
Shortly after entering into the 1983 agreement, the Airport Board then initiated a study to
investigate methods of mitigating the aircraft noise levels. This resulted in the development of
a new comprehensive noise control program for the Airport. The Noise Control Program
includes a number of elements in addition to the cumulative and single event limits described
above. The major elements of the program are summarized below:
• Limitation on the scheduling of night operations by commercial turbojet air
carrier aircraft and a voluntary curfew on General Aviation night operations.
• A preferential runway program that requests that all aircraft depart to the south
and arrive from the south when wind conditions permit.
• A request that all aircraft departing to the south make an immediate left turn,
weather conditions permitting. This procedure is seldom utilized today because
it is no longer an FAA-published procedure.
• A request that aircraft entering the area from the south, but landing from the
north, perform a left downwind turn near Blacktail Butte, when weather
conditions permit. Right downwind turns over the Park are discouraged.
• A comprehensive operational and noise-monitoring program that documents the
level of compliance with these noise abatement procedures.
• A voluntary Fly Quiet Program.
In order to ensure compliance with cumulative noise limits of the Agreement, the Airport Board
conducts annual noise measurements. These measurements are conducted for approximately a
one-week period during the peak winter and summer seasons. This report presents the results
Section 2 Background Information on Noise
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2020 Annual Report Page 2-
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of the 2021 winter noise measurements, and documents compliance with the noise limits
contained in the 1983 Agreement between the Airport Board and the Department of Interior.
2.2 Noise Metrics
The description, analysis and reporting of community sound levels from aircraft is made
difficult by the complexity of human response to sound and the myriad of noise metrics that
have been developed for describing acoustic impacts. This analysis utilizes the two major noise
metrics for analysis of aircraft noise impacts: Day Night Noise Level (DNL), and the Maximum
Noise Level (Lmax). Both of these metrics are based on the A-weighted decibel (dBA).
DNL, the primary metric for analysis, is a “cumulative” noise metric because it represents a
measure of the total noise over a 24-hour period. Cumulative noise metrics have been
developed to assess community response to noise. They are useful because these scales attempt
to combine the loudness of each event, the duration of these events, the total number of events,
and the time of day these events occur into a single number rating scale. They are also designed
to account for the known health effects of noise on people. The FAA, the EPA, and various
other agencies use DNL in assessing noise and land use compatibility.
Lmax is a measure of single event noise that describes the loudness of a single flyover
regardless of the time of day or the number of such events. Lmax is the peak or loudest sound
reach during an aircraft flyover. There are no noise and land use compatibility standards in
terms of Lmax. Disturbances from aircraft noise (i.e., speech and sleep interference) however
can be related to Lmax levels. In general, it is the metric that is more easily related to by the
public in that it is what is experienced for each flight. But it does not factor in how often these
events occur. The DNL also takes into account the loudness of the events and how often they
occur.
Section 2 Background Information on Noise
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2.3 Noise Assessment Guidelines
Noise/Land use guidelines have been developed by a number of agencies including the Federal
Aviation Administration. As a means of implementing the Aviation Safety and Noise
Abatement Act, the FAA adopted Regulations on Airport Noise Compatibility Planning
Programs. The guidelines specify a maximum amount of noise exposure (in terms of the
cumulative noise metric DNL) that will be considered acceptable to, or compatible with, people
in both living and working areas. Residential land use is deemed compatible for noise
exposures up to 65 DNL.
As part of the Agreement with the Department of Interior, Jackson Hole Airport is required to
comply with certain noise limits within Grand Teton National Park. These limits are in terms
of the DNL noise levels. One requirement is that the annual noise level from aircraft measured
at the Moose location cannot exceed 55 DNL. This is the southeastern corner of the area defined
as the noise sensitive areas of the park. This area is shown in Figure 2-1. In addition, the
Critical Area Boundary Line, also shown in Figure 2-1 sets the limit beyond which the aircraft
annual noise level cannot exceed 45 DNL.
Section 2 Background Information on Noise
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2.4 Methodology in Determining the Noise Environment
The noise environment at Jackson Hole Airport was determined through the employment of
comprehensive noise measurement from the airport’s permanent monitoring system of aircraft
and ambient noise sources, then incorporating these results into the FAA's airport noise
computer model (AEDT). The noise measurement surveys determine the DNL noise level, the
Lmax levels from each aircraft flyover, the sound exposure level (SEL) and the background or
non-aircraft ambient noise environment.
The measurements are annualized by correlating the measured noise events results with the
flight radar that caused that event. The results of the measurements, in conjunction with annual
airport operational data, are incorporated into the FAA's Aviation Environmental Design Tool
(AEDT) software program through which annual average noise levels at any location around
the airport can be predicted. The noise environment is commonly depicted in terms of lines of
equal noise levels, or noise contours. Note in past years, the measurements were conducted
seasonally.
Noise measurements are conducted at six (6) locations around the airport. These locations
include Moulton Loop, Moose, and Barker Ranch and are illustrated in Figure 1-1. The
Moulton Loop measurement site is indicative of the residential area directly south of the airport,
which is directly under the extended runway centerline approximately 2,200 feet south of the
runway end and is one of the areas exposed to the highest noise levels. Note: In 2003, the
Moulton Loop site was moved approximately 200 feet closer to the runway end than the old
temporary site. This results in slightly higher noise level readings. This location falls under
the Federal Aviation Administration noise and land use compatibility guidelines, which
recommend that residential land uses should not be exposed to noise levels in excess of 65
DNL.
The Moose measurement site is located in the National Park, south of Teton Park Road and
directly under the extended runway centerline. The Lease Agreement with the National Park
requires that the aircraft noise levels at this location not exceed 55 DNL. The Barker Ranch
measurement site is also within the National Park, along Moose Wilson Road northwest of the
airport. This site is on the restriction line that requires that aircraft noise levels not exceed 45
DNL.
Section 3 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 3-1
3.0 Operational and Flight Data
3.1 Aircraft Operations
The 2020 aircraft operations were derived directly from the airport summary of daily logs, the
Airport’s noise monitoring system radar data and the FAA’s OPSNET data. The 2020 annual
operations along with data from 2001 to the most recent period are presented in Table 3-1. The
total number of operations during the twelve-month period was 29,122 or 79.8 average daily
operations. The total operations showed an increase in operations while commercial and
regional jet operations decreased. An operation is either 1 departure or 1 arrival. This included
5,854 commercial jet operations, 1,934 regional jet operations and 14,628 corporate jet
operations.
The operations have seasonable differences in the operations with more activity during the
summer and winter months. This is shown in Figure 3-1 that presents the monthly activity of
Total operations, Commercial/Regional and Corporate Jet activity. August had the higher
number of operations during the 2020 time period.
3.2 Enplaned Passengers
The total number of enplaned passengers was also presented in Table 3-1. For the 2020 annual
period, there were 284,433 enplaned passengers. This shows a reduction as compared to past
years as a result of the Covid-19 pandemic.
Section 3 Operational and Flight Data
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2020 Annual Report Page 3-2
Table 3-1
Annual Operations and Enplaned Passengers
AIRCRAFT ANNUAL OPERATIONS
YEAR
COMMERCIAL
REGIONAL
CORPORATE
OTHER
TOTAL
ENPLANED
JET
JET
JET
PASSENGERS
2020
5,854
1,934
14,628
6,706
29,122
284,433
2019
7,096
2,480
11,346
6,403
27,325
454,629
2018
6,018
2,670
11,972
6,303
26,963
391,353
2017
5,632
2,322
11,794
9,241
28,989
353,776
2016
5,212
3,008
10,422
11,737
30,379
346,127
2015
4,582
2,798
10,104
10,656
28,140
316,674
2014
4,062
3,100
9,372
9,583
26,117
305,186
2013
3,592
2,530
8,822
8,549
23,493
292,176
2012
3,586
2,698
8,440
11,354
26,078
272,888
2011
3,868
2,840
8,484
10,584
25,776
281,808
2010
4,112
2,722
7,904
10,869
25,607
286,660
2009
3,738
2,736
7,702
14,826
29,002
281,674
2008
4,110
2,648
9,252
14,209
30,219
304,393
2007
3,514
2,358
10,862
13,871
30,605
275,569
2006
3,676
2,506
10,204
15,848
32,234
271,416
2005
3,774
592
10,510
18,196
33,072
241,925
2004
3,106
50
9,744
18,893
31,793
208,000
2003
3,646
334
8,844
20,769
33,593
212,731
2002
2,304
12
8,240
25,422
35,978
179,510
2001
1,666
584
7,374
30,974
40,598
169,249
Source: FAA Opsnet and Jackson Hole Airport Noise Monitoring System
Section 3 Operational and Flight Data
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2020 Annual Report Page 3-3
Figure 3-1
Month-to-Month Operations for 2020
Section 3 Operational and Flight Data
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2020 Annual Report Page 3-4
3.3 Noise Measurement and Analysis Procedures
The following section outlines the methodology used to measure and quantify noise levels from
aircraft operations and ambient noise level conditions. Measurement methodology and analysis
techniques used in the study are also included.
Continuous Measurement of the Noise
The methodology employed in this study uses the continuously recorded one second LEQ noise
levels at each of the six permanent measurement locations. These permanent noise monitors
were installed in 2003. From this data different noise metrics can be calculated. This includes
the aircraft single event noise event level (Lmax), cumulative daily noise levels (DNL), and the
ambient levels. Since all the noise is collected during the measurements, it is possible to post
process the data and calculate different metrics of interest that may arise. The process of
calculating noise events from this data uses a floating threshold methodology. This allows for
the measurement and identification of lower noise level aircraft events. The parameters are
adjustable and can be modified so that it is possible to recalculate noise events from raw data
any time in the future.
3.4 Aircraft Operational and Radar Track Data
Initially the airport did not have the ability to obtain radar track information. In fall of 2008,
the FAA installed a BI-6 radar system at the airport. With the installation of radar, the noise
monitoring system was also upgraded to obtain this data. The upgrade consisted of numerous
components, including access to the BI-6 radar data, weather data, and the additional of new
features to the remote noise monitoring stations. The BI-6 radar data connection allows for the
noise monitoring system to correlate an aircraft noise event to the aircraft causing the event. At
the same time the noise monitoring sites were also upgraded to measure
detectability. Detectability approximates the Volpe Center’s standards for measuring aircraft
noise in a park setting using other metrics. The audible contribution of aircraft and other noise
sources to the Park’s natural quiet can be approximated using the detectability metric. The
upgrade allows the noise monitoring system to more accurately measure the aircraft noise levels
at the noise measurement points and to also quantify the aircraft audibility levels at these
locations.
The BI-6 radar was the primary source for aircraft operational information however initially the
data was just radar tracks and not any aircraft identification. In 2014 a national radar feed
became available that that the airport subscribes to that provided both radar track and flight
information data. The airport maintains a live feed of all the IFR aircraft activity in the United
States directly from FAA center data. This provides data on all domestic civilian IFR aircraft,
and the data stream includes aircraft type, position and altitude by time. VFR aircraft are often
tracked, but typically is no ID information. The radar coverage in the valley does not reach the
airport surface, so operations near the airport and low altitude flights were not typically tracked
by this data source.
Section 3 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 3-5
In 2020, the FAA’s ADS-B NextGen tracking system became operational nationwide which
greatly increased the coverage and accuracy of the radar data. The airport also installed a
ground station at the airport that allowed for better coverage of operations at low altitude around
the airport. The ADS-B radar data includes flight information for every ADS-B equipped flight,
as well as position information as to the location of the flight. Each flight is also assigned a
unique identification track number so all of the data for any particular flight can be compiled.
The flight information includes data such as the aircraft type, airline code, departing and
arriving airport codes, aircraft unique tail number and flight ID number. The position
information includes the X and Y coordinates as well as the altitude of the aircraft at each point
at greater accuracy then with conventional radar information. The location information given
provides the information necessary to determine the direction of flow for runway usage.
The ADS-B surveillance requires an aircraft to be equipped with an ADS-B transponder and
that it is turned on. All commercial and large general aviation aircraft have this equipment, and
it is turn on during flight. Smaller visual flight aircraft are no required to have this equipment
to operate in non-busy airspaces, but most aircraft do. There will be some visual flight rules
aircraft that are not tracked by ADS-B.
Correlation of Noise and Flight Data
The noise monitoring software was used to help correlate aircraft flight activity to the noise
data. This software utilizes such methods as aircraft position information (The position of the
aircraft at the time of the noise events to correlate the aircraft to the noise event), noise event
sequencing, and noise event profiling to correlate noise data to the aircraft activity. The noise
event profiling is used to identify characteristics of both the aircraft and non-aircraft noise
events.
Calculation of Aircraft Noise Metrics
Once the collection and correlation of the noise and flight data is complete, the various noise
metrics can be calculated. A computer process is used to calculate the single event, cumulative,
and ambient noise metrics of interest from the data collected at each of the noise monitoring
sites. This includes the ambient background dBA noise levels, the Lmax single event noise
levels, the DNL cumulative noise levels.
Section 4 Operational and Flight Data
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2020 Annual Report Page 4-1
4.0 Annual Noise Measurement Results
4.1 Introduction
The existing noise environment for Jackson Hole Airport was determined through a noise
measurement survey. The results of the measurement survey are summarized in the following
paragraphs. This section presents noise survey information for the Spring & Summer 2020
season as well as the annual 2020 annual noise measurement results. This section presents the
overall findings from the noise measurement survey. This includes an explanation of the results
and is divided into the following sub-sections:
Noise Measurement Results
Continuous noise measurement data
Ambient noise measurement results by hour
Single event noise measurement results (Lmax)
DNL daily noise measurement results
The airport’s permanent noise monitoring system utilizes 01dB Opera and CUBE noise
monitors at all of the measurement sites. The permanent monitoring system is state-of-the-art
and complies with all specific International Standards (IEC), and measurement standards
established by the American National Standards Institute (ANSI) for Type 1 instrumentation.
The data collected by the permanent monitors includes the continuous measurement of 1-second
average or equivalent (LEQ), noise levels. This type of measurement system allows for the
measurement and identification of Lmax noise events at a lower threshold than the equipment
previously used at this site. This allows for a more accurate measurement of lower aircraft
noise levels that are typical of the sites in the Park. Analysis of this data resulted in the single
event noise levels from each individual flyover, hourly data and the daily DNL noise levels for
the measurement period.
Section 4 Operational and Flight Data
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2020 Annual Report Page 4-2
The report presents data for the annual levels, and during peak periods in the summer and
winter seasons. Presenting season data along with the annual data is In keeping with the
original reporting periods and focuses on the times when operations are at their highest levels.
4.2 Continuous Noise Measurement Data
Noise levels are continuously recorded at each of the noise-monitoring sites. In addition to
recording the noise events from aircraft, monitors also record the ambient noise level of the
community surrounding the site. A sample of this data is presented in Figure 4-1 which
displays a 15-minute segment of continuous noise data that was measured at Site 2, at Golf.
The measured A-weighted noise level value is shown on the vertical axis and time of day, in
minutes, is displayed on the horizontal axis. The difference between an aircraft event and the
ambient noise can be easily distinguished in this plot with each of the peaks generated by an
aircraft overflight. For this example, the peak noise levels from the aircraft flyovers were in
the mid 60s and low 70s dBA. The ambient levels between aircraft events were in the mid 30s
dBA.
Section 4 Operational and Flight Data
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2020 Annual Report Page 4-3
Figure 4-1
Sample Time History Noise Plot of Aircraft and Ambient Noise
Section 4 Operational and Flight Data
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2020 Annual Report Page 4-4
4.3 Ambient Noise Measurement Results
Background, or ambient noise levels, (those without aircraft noise) are measured at each of the
monitoring locations, and these results are presented using Percent Noise Levels (Ln). Percent
Noise Level characterizes intermittent or fluctuating noise by showing the noise level that is
exceeded during a significant percent of time during the noise measurement period. Ln is most
often used to characterize the statistical distribution of measured noise levels. For example,
L90 is the noise level exceeded 90 percent of the time, L50 is the level exceeded 50 percent of
the time, and L10 is the level exceeded 10 percent of the time. Typically, L90 represents the
background noise level; L50 represents the median or ambient noise level, and L10 the most
intrusive noise levels.
Other noise sources that are part of the background noise environment include roadway, wind
in the trees, and people activities. This data aids in assessing how intrusive aircraft noise is on
the ambient environment.
Results of the ambient noise measurement survey at each measurement site are displayed in the
following figures and tables. Table 4-1 presents the statistical summary of the ambient
measurements for the entire measurement period at each site using the Ln noise levels for the
Lmin, L90, L50, L10 and Lmax. The Lmax (Maximum Noise Level) is presented for the
loudest 1-second dBA value that was measured while the Lmin (Minimum Noise Level) is the
lowest 1-second dBA value that was measured. This table illustrates the range in noise levels
that exist at each site. Note that aircraft noise events are included in this data and are typically
the source of the peak or maximum noise levels.
Section 4 Operational and Flight Data
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2020 Annual Report Page 4-5
Table 4-1
Annual Ambient Noise Measurement Results
Site
Name
Statistical Noise Levels (dBA)
Lmax
L10
L50
L90
Lmin
1
Moulton Loop
98
58
43
34
28
2
Golf Course
90
50
42
38
34
3
Barker Ranch
76
45
41
38
33
4
Moose
81
47
40
37
33
5
4 Lazy F Ranch
80
44
38
35
32
6
Timber Island
82
49
35
24
19
Industry practices indicate that L90 is a good representation of the background noise level and
L50 the ambient noise level. These represent the levels that are exceeded 90 percent of the time
and 50 percent of the time, respectively. The L90 is referred to as the residual noise, when
other sources of noise are not present, and is the level above which noise events occur, such as
an aircraft overflight or a vehicle pass-by. Aircraft noise would have very little if any
contribution to this noise level because of the relatively short duration of these noise events.
The L50 noise level is referred to as the median or ambient noise level. Half the time the noise
is below this level, and half the time it is above this level. Even during peak hours of aircraft
activity, the L50 noise level would not be influenced by the aircraft noise. On a 24-hour basis,
this level is generally reflective of ambient noise levels.
The measurements show that background L90 noise levels ranged from a low of 24 dBA to a
high of the high 30s dBA. Most sites had an average L90 noise level right around the mid 30s
dBA. The ambient L50 noise levels ranged from the mid 30s dBA to the low 40s dBA. The
majority of these sites are located in relatively quiet settings that are not exposed to other noise
sources, such as highways or people activities.
Ambient noise levels vary by day and time of day as summarized in the data from the Moulton
Loop site which is presented in Figure 4-2. The Figure shows each hour of ambient
measurement data for one typical day (January 4
th
2020). Day-to-day ambient noise levels are
generally similar with higher levels occurring during high wind conditions. Ambient noise
levels vary by time of day with quieter levels typically occurring during night and early morning
hours, and with higher levels occurring during daytime hours. Typical quiet ambient noise
hours range from 5 to 10 dBA lower than average hours.
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-6
Figure 4-2
Site Specific Ambient Noise Measurement Results
Moulton January 4, 2020
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-7
4.4 Aircraft Single Event Noise Measurement Results
Aircraft single event noise levels were identified at each measurement site. The acoustic data
included the maximum noise level (Lmax) as well as other noise metrics used in noise model
validation. The single events measured during the survey were correlated with flight operations
information. With this correlated single event noise data, it was possible to separately identify
the single event noise levels from the different sources of aircraft noise. The single event results
are summarized in the following paragraphs.
The single event data were analyzed in terms of the distribution of events by calculated single
event noise level. An example of the range in noise data is presented for two sites in Figure 4-
3. This figure presents the average Lmax noise level by category of jet and a histogram of
Lmax values for all the aircraft events that were measured at the Moose site and at the 4Lazy F
Ranch site. These are all jet arrivals to the south on Runway 19. The histogram shows the
measured Lmax noise level on the horizontal axis and the number of measured aircraft events
with that Lmax level on the vertical axis. The Moose site is representative of a location closest
to the airport to the north while the 4Lazy F Ranch site is representative of a location more
distant from the airport. These results show the wide range in noise level generated by aircraft
events that occur at each site and the deference in noise by category of jet aircraft.
Figure 4-4 presents the same results for two sites to the south. The Moulton and Golf Site
which are primarily exposed to departure noise on Runway 19. This data also shows the ranges
in single event noise levels by total and by category of jet aircraft.
The single event data were also analyzed in terms of noise level per aircraft type. Examples of
the single event noise level by aircraft type are presented in Figure 4-5. This figure displays
the average single event noise level by aircraft type for departures measured at Moulton Loop
and the average Lmax by aircraft type for arrivals measured at Moose. These figures show the
type of aircraft commercial and regional jet aircraft, the number of measured noise events
correlated to that aircraft type, and the average single event noise level measured for that aircraft
type. The longer bar graph illustrates those aircraft with the loudest events. The louder events
were generally produced by older generation aircraft. These data illustrate the difference in
noise levels generated by departure operations versus arrival operations. The data shows that
departure events generate higher noise levels and a wider range in noise per the different aircraft
types.
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-8
Figure 4-3
Noise Event Summary and Histogram Report
Moose and 4LAZYF Sites - Arrivals on Runway 19
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-9
Figure 4-4
Noise Event Summary and Histogram Report
Moulton and Golf Sites – Departures on Runway 19
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-10
Figure 4-5
Range of Noise by Aircraft Type (Commercial and Regional Jet)
Section 4 Operational and Flight Data
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 4-11
4.5 DNL Noise Measurement Results
Aircraft-related DNL levels were calculated for each of the six long-term noise monitoring
locations. Table 4-2 presents the results of the DNL noise measurements at the six noise-
monitoring locations. This table lists the average aircraft-related DNL for annual noise levels
for 2020.
Table 4-2
Aircraft DNL Noise Measurement Results
Jackson Hole Airport 2020 Annual Report
Site #
Name
Description
Aircraft
DNL
1
Moulton Loop
Zenith Drive and Spring Gulch Rd.
62
2
Golf Course
Jackson Hole Golf & Tennis Club
51
3
Barkers Ranch
Circle H Ranch (Barker’s Residence)
31
4
Moose
Moose Entrance
52
5
4 Lazy F Ranch
4 Lazy F Ranch
47
6
Timbered Island
East of Timber Island
33
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-1
5.0 Annual Noise Contours
5.1
Introduction
Contour modeling is a key element of the report; generating accurate noise contours is largely
dependent on the use of a reliable, validated, and updated noise model. The FAA's Aviation
Environmental Design Tool (AEDT) was used to model the flight operations at Jackson Hole
Airport. The AEDT has an extensive database of civilian aircraft noise characteristics.
Airport noise contours were generated in this study using the FAA’s AEDT 3d. The latest
version, Version 3d, was released for use on March 29, 2021, and is the state-of-the-art in airport
noise modeling. The AEDT is a large computer program developed to plot noise contours for
airports. The program is provided with standard aircraft noise and performance data for over
200 aircraft types that can be tailored to the characteristics of the airport in question. Version 3d
includes updated databases that include some newer aircraft, the ability to include run-ups in the
computations, the ability to include topography in the computations, and the provision to vary
aircraft profiles in an automated fashion.
One of the most important factors in generating accurate noise contours is the collection of
accurate operational data. The AEDT program requires the input of the physical and operational
characteristics of the airport. Physical characteristics include runway coordinates, airport
altitude, temperature and optionally, topographical data. Operational characteristics include
various types of aircraft data. This includes not only the aircraft types and flight tracks, but also
departure procedures, arrival procedures and stage lengths that are specific to the operations at
the airport. Aircraft data needed to generate noise contours include:
• Number of aircraft operations by type
• Types of aircraft
• Day/Evening/Nighttime distribution by type
• Flight tracks
• Flight track utilization by type
• Flight profiles
• Typical operational procedures
• Average Meteorological Conditions
5.2 Existing Aircraft Operations
The existing noise environment for Jackson Hole airport was analyzed based upon the 2020
annual operations. The data was derived from various sources, which include aircraft tower
counts and noise monitoring system operational data. A variety of operational data is necessary
in order to determine the noise environment around the airport. This data includes the following
summary information and is discussed in detail in the following paragraphs:
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-2
• Aircraft Activity Levels
• Fleet Mix
• Time of Day
• Runway Use
• Flight Path Utilization
The tower count data showed that for the period 2020 period there were a total of 27,218 annual
operations, or an average of 74.6 operations per day (an operation is one takeoff or one landing).
The breakdown by aircraft category was determined from a variety of sources that include:
• Airport Radar
• Operations Network (OPSNET)
The 2020 season aircraft operations for each category of operation are summarized in Table 5-
1. These operations are categorized as general aviation, business jets air taxi, commuters,
regional and commercial jets. The total number of annual corporate jet aircraft was determined
from the airport radar data source. The airport radar provides information on aircraft that file an
instrument flight plan. It accounts for nearly all larger aircraft including corporate jets. Larger
twin-engine propeller aircraft are also counted in airport radar, but smaller aircraft flying under
visual flight rules are not always included. The AEDT model was based upon a compilation of
all 27,218 operations at the airport.
Table 5-1
SUMMARY OF OPERATIONS, (2020)
Jackson Hole Airport 2020 Annual Report
Category Type
Annual
Operations
Daily
Operations
Percent
Nighttime
Commercial Jet
5,506
15.1
0.4%
Regional Jet
1,908
5.2
0.4%
Small Commuter
0
0
0.0%
Air Taxi (TurboProp)
2,836
7.8
1.0%
General Aviation
Business Jet
13,025
35.7
1.2%
Turbo/Piston Propeller
3,393
9.3
3.3%
Helicopter
408
1.1
0.0%
Military
144
0.4
0.0%
Total Operations
27,218
74.6
0.7%
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-3
Fleet Mix. The fleet mix of aircraft that operate at the airport is one of the most important factors
in terms of the aircraft noise environment. The corporate jet fleet mix data was determined from
an extensive review of the airport radar database.
Time of Day. In the DNL metric, any operations that occur after 10 p.m. and before 7 a.m. are
considered more intrusive and are weighted by 10 dBA. Therefore, the number of nighttime
operations is very critical in determining the DNL noise environment and is also very important
to the residences around Jackson Hole Airport. The nighttime operations assumptions were
estimated from a variety of sources. This included a review of the airport radar data. The
nighttime operational assumption data are summarized in Table 5-1.
Runway Use. An additional important consideration in developing the noise contours is the
percentage of time each runway is utilized. The speed and direction of the wind dictate the
runway direction that is utilized by an aircraft. From a safety and stability standpoint, it is
desirable, and usually necessary, to arrive and depart an aircraft into the wind. When the wind
direction changes, the operations are shifted to the runway that favors the new wind direction.
For the Jackson Hole Airport, wind is generally calm with the predominate wind direction being
from the south. Runway 19 is utilized more than the reverse runway direction, Runway 01.
Flight Path Utilization. The Airport Board has established paths for aircraft arriving and
departing Jackson Hole Airport. These paths are not precisely defined ground tracks but
represent a broad area over which the aircraft will generally fly. The modeling analysis
includes a total of eight departure flight tracks and six arrival flight tracks to model the aircraft
flight paths at Jackson Hole Airport. Aircraft flight tracks were obtained by observations
during the measurement survey, discussions with airport staff and air traffic control personnel,
and a review of aeronautical charts.
A sample of the 2020 flight tracks use in AEDT modeling are presented in Figure 5-1 and 5-2.
Figure 5-1 presents departure and arrival flight paths for jets in south flow on Runway 19.
Figure 5-2 presents departure and arrival flight paths for jets in north flow on Runway 01. The
flight track data was used to help define the location of the aircraft flight paths and in the
correlation of the noise measurement data with the aircraft operational data.
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-4
Figure 5-1
Jet Arrival and Departure Flight Tracks
South Flow Runway 19
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-5
Figure 5-2
Jet Arrival and Departure Flight Tracks
South Flow Runway 01
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-6
5.3 Noise Modeling Results
The noise metric used to assess the 2020 annual noise contour is the Day Night Noise
Level (DNL). This model run uses FAA standard modeling assumptions that would be
required within a Part 150 or FAA sponsored environmental study. The DNL index is a 24-
hour, time-weighted energy average noise level based on the A-weighted decibel. It is a
measure of the overall noise experienced during an entire year of flight operations. The
time-weighted refers to the fact that noise that occurs during certain sensitive time periods
is penalized for occurring at these times. In the DNL scale, noise occurring between the
hours of 10 p.m. to 7 a.m. is penalized by 10 dB. This penalty was selected to attempt to
account for the higher sensitivity to noise in the nighttime and the expected decrease in
background noise levels that typically occurs in the nighttime. The 2020 AEDT contours
are presented in Figure 5-3.
Section 5 Computer Modeling
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 5-7
Figure 5-3
2020 Annual DNL Noise Contour
Section 6 Summary
Jackson Hole Airport BridgeNet International
2020 Annual Report Page 6-1
6.0 Summary
6.1
Overall Summary
The principal reason for the reduction in noise that has occurred at the airport since 1984 is the
increased utilization of new generation Stage 3, 4 and now 5 aircraft that are substantially
quieter than the aircraft that predominantly served the airport in the past. The results of the
noise measurements show that the airport is in compliance with the requirements of the Airport
Use Agreement. The measured noise levels are below the limits contained within the
agreement. The requirements are that the annual DNL noise level contour from aircraft noise at
the Moose measurement location cannot exceed 55 DNL and at the Barker site cannot exceed
45 DNL. The 65 DNL noise contours do not extend beyond the airport boundary. There are
no residential land uses exposed to noise levels in excess of 65 DNL.