Ted Stevens Anchorage International Airport (FAR)
Part 150 Noise Compatibility Study Update
Study Input Committee Summary Notes
November 7, 2012 1:30 p.m. AirfieldMaintenance Facility
NAMEAFFILIATIONPRESENT √
Staff and Consultants
John Parrott ANC √
John JohansenANC √
Trudy WasselANC √
Ryk Dunkelberg Barnard Dunkelberg & Company √
Kate AndrusBarnard Dunkelberg & Company √
Vince MestreLandrum and Brown √
Mary VigilanteSynergy Consultants √
Wende WilberCRW Engineering Group√
Eva WelchAECOM√
Committee Members
Merle AkersTurnagain Community Council √
Bob AuthSpenard Community Council √
Judy ChapmanCitizen Representative√
Bruce GreenwoodFAA √
Mary LeeCitizen Representative √
Jim SeeleyLHD Pilot Association √
Patricia SullivanFAA Airports Division √
Thede TobishMunicipality of Anchorage, Community Development √
Breck TostevinTurnagain Community Council √
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Summary Notes
Mr. Dunkelberg began the third meeting of the Federal Aviation Regulations (FAR) Part 150 Noise Compatibility Study Update Input Committee by presenting the meeting agenda as follows:
Introductions
- Airport Staff
- Study Team
- Committee Members
Meeting Protocol
Brief Refresher on Part 150 Study
- What is a Part 150 Study?
- Why Update Study?
- Study Process
Description of Noise Metrics
Noise Monitoring
- Background
- Results
Forecasts
Draft Contours
- Previous Part 150 Approved Contours (1999)
- Draft 2009 Contours
- Draft 2020 Contours
- Comparison of 1999 versus 2020 contours
Questions/Comments
- Study Committee Members
- Members of the Public
Introductions
Mr. Dunkelberg introduced the Part 150 Study team and gave a brief overview of all the other entities involved in the noise study.
Committee Role and Meeting Protocol
Mr. Dunkelberg stated that the Study Input Committeeis expected to act as a major resource for the Airport staff and Consultant team in developing alternatives for the Part 150 Noise Study. He asked that all questions wait until the technical portion of the presentation is completed. Then, questions will be taken from each member in turn, so that all committee members get a chance to ask questions and pose comments. Members of the public who attend Study Input Committee meetings will be allowed to speak at the close of committee business.
Study Details
Mr. Dunkelberg reviewed that the purpose of the Part 150 Noise Compatibility Study is to identify existing noise exposure surrounding the Airport, identify potential future noise exposure, evaluate various alternatives to reduce the number of people affected by noise, and to make recommendations as to viable abatement/mitigation measures to reduce the number of people affected by noise living near the Airport. The noise study generally has a five year planning horizon and identifies and evaluates both current and future aircraft noise and land use. There are two distinct parts of a Part 150 Noise Compatibility Study; Noise Exposure Maps (NEMs) and a Noise Compatibility Program (NCP). After a complete analysis of noise and land use conditions at the Airport, both the NEMs and the NCP will be submitted for approval or disapproval by the Federal Aviation Administration (FAA). If approved, the measures and recommendations contained in the NCP are eligible for implementation and federal funding.
Why Update Study?
Mr. Dunkelberg went over the primary reasons the Airport is updating the existing Part 150 Study. For the Airport to continue to receive federal funding for noise mitigation it must have current noise exposure maps and the current NEMs are over 10 years old. Additionally there have been changes in aircraft fleet mix, aircraft noise levels, change in aircraft activity levels, changes in airfield development and the release of an updated Integrated Noise Model (INM).
Noise Metrics
Mr. Dunkelberg introduced Vince Mestre to discuss the results of the noise monitoring conducted during two periods, one during the winter and one during the summer. Mr. Mestre first described various noise metrics examined including the Day-Night Noise Level, the LEQ (one hour equivalent noise level), L10 (sound level exceeded 10 percent of the time), L50 (sound level exceeded 50 percent of the time), and L90 (sound level exceeded 90 percent of the time).
Noise Monitoring Background
Mr. Mestre discussed purpose of noise measurement. These measurements are used to validate the FAA Integrated Noise Model (INM). He stated that measurements are taken of the actual noise levels an aircraft makes at a particular airport under particular conditions to compare them to predicted noise levels from the FAA INM using the exact same conditions. Although not required for a Part 150 Noise Study, these actual measurements increase confidence in the Study results and account for special conditions at particular airports. Noise measurements were taken during two seasons, summer and winter at 30 different sites. Noise data from the Airport’s permanent noise monitors were taken for the base case year of 2009.
Noise Measurements
Mr. Mestrethanked the volunteers who allowed noise monitors to be placed at their homes and then described the generalized results of the noise monitoring periods. Generally, the ambient noise levels (the noise without any aircraft) were much lower than other built environments. Looking at the various sites, generally the noise of single events was similar in the summer as in the winter, but in the summer there were generally more noise events, particularly by those sites near the Lake Hood Seaplane Base. Flight track data from both the noise monitoring periods, as well as 2009 flight track data indicated that jet flight tracks generally show departures to the north, and arrivals from the west (directing most of the jet operations over the water rather than non-compatible land uses). This preferential runway use was sometimes used prior to the last Part 150 Study, but as a recommendation of the previous Part 150 Study its use has increased. For prop flight tracks, there was a considerable difference between the flight tracks in the summer and the winter, with summer operations being much higher due to the operations at Lake Hood Seaplane Base. Overall, the ambient levels were much lower than most urban/suburban environments, and the aircraft noise levels were typical of a medium hub airport.
Draft Noise Contours.
Mr. Mestrepresented the draft noise contours for 2009 and 2020 based on the Alaska International Airport System (AIAS) forecasts. Both the 2009 and 2020 contours are smaller than those produced in 1999 as part of the previous noise study. While there were changes in the operations and fleet mix, the biggest difference in the contour is likely explained by more aircraft using the preferential runway use directing jet operations over the water rather than to the south and east over non-compatible land uses. He reminded the committee that these are draft contours and changes might occur.
Next Steps and Public Involvement.
Mr. Dunkelberg explained the next steps, including refinement of the contours, land use analysis (how many people and non-compatible land uses are within the contours), and that next year the committee will start alternatives development. The draft noise measurement report will be distributed to the committee in the next month. He also invited members of the committee to attend the second Part 150 Noise Study Public Information Meeting to be held tonight at 5:30 p.m.
Questions and Comments
Question: Some people previously provided comments on the draft working papers. Will we see how those comments were addressed?
Answer: We will consider all comments and make changes as necessary. You will see the changes when we release the Draft Study, which will have all necessary changes incorporated.
Question: How do you create the contours?
Answer: The FAA requires the use of the Integrated Noise Model (INM) which is a complex computer model that takes into account fleet mix, operations, flight tracks and time of day.
Question: In the graphic comparing the 1999/2020 contours, can you explain the difference on the east side of the Airport? If a large jet departed that way, you would not be able to hear talking, yet you mentioned that 60-65 decibels is the range of the human voice.
Answer: So the contours are based on the Day-Night Noise Level which is an annual average of the noise. This means that there are single event noise levels much louder than 65 decibels, but that the average is less than 65 DNL. The contour is so small on that side because there are so few operations that occur over the non-compatible land uses to the east. There are not enough operations on that side to bubble out the contour to the extent that it was in 1999 when a smaller percentage of aircraft were using preferential runway use (compared to today) and a good portion of the operations occurred over the non-compatible land uses on the east of the Airport. DNL is often criticized because it is an average and does not represent what people actually hear (single event level). But DNL is the required metric. It is important to note that just because DNL might be below 65 DNL, single event noise levels will occur that are much louder than 65 decibels.
Question: For the winter/summer noise monitoring, does it include ground noise?
Answer: Yes. The noise monitors did pick up some ground noise. Ground noise will be examined more closely in the next phase.
Question: The contours shrank since 1999, were there other reasons for this other than the change in flight tracks?
Answer: Yes, in addition to the flight track change there was also a change in the fleet mix, with some of the louder aircraft being phased out because they are at the end of their maximum usable life. So there are fewer of the noisier aircraft in the fleet mix for 2020.
Question: When aircraft run for a long period of time at night, will those types of things be analyzed in the Study?
Answer: Yes, those are called ground run-ups and will be examined in the next phase of the Study.
Question: Are some of the newer planes (like a 777 or Dreamliner) quieter?
Answer: Yes, they are generally much quieter than the planes they replace.
Question: Do aircraft manufacturers give you noise levels prior to production?
Answer: Aircraft manufactures typically supply general noise of new aircraft; however, these need to be approved by the FAA prior to having it put as a new aircraft type in the INM. In the meantime, the model uses a surrogate aircraft in place to estimate the noise impacts. The surrogate is typically very conservative and represents a louder noise level than the actual noise levels of a new aircraft.
Question: Do the 2020 contours have weather trends factored in?
Answer: The average annual temperature is included in the model. However meteorological changes have a complex relationship with the propagation of sound. Patterns such as a temperature inversion can allow sound to propagate very differently. Generally, this effect increases the further you are from the source. So within the 65 DNL contour, it has little effect, and you would not see a large change in the contours. But you can have a much larger effect the further away from the Airport you get.
Question: You mentioned that there were semi-permanent sites and permanent sites. What is the difference?
Answer: We collected data from two types of sites during the monitoring periods in summer and winter. Sites 1-10 are considered semi-permanent and collected between 161-321 hours of data. Sites 11-30 are considered short-term and data was collected for approximately one day at each of these sites per season. Then, we also took data from the Airport’s permanent noise monitoring system for the entire 2009 year. These noise monitors are currently not operational, but we were able to get the data it collected for the entire year of 2009.
Question: What happens between now and 2020? Why is this not based on now/2020?
Answer: The 2009 contour is required to create a base case scenario for the last full year of operations with the Airport operating with no closures or other operational variations. 2020 will be the contour used to determine non-compatibility within the 65 DNL. Generally, this is in favor of the residents since operations generally increase over time and therefore the 65 DNL contour would be larger, making the 65 DNL contour in the future a more conservative estimation of the land use impacts. Additionally, the Study will take several years to complete and become approved before any recommendations are approved for implementation. Applying for funding, securing funding, accomplishing the necessary environmental reviews and implementing the recommendations takes time, which means that 2020 is close to the potential timeframe when recommendations might be approved for implementation based on the Part 150 schedule.
Question: Why have not all the previous Part 150 Study recommendations been implemented?
Answer: The needs of noise programs generally exceed the funding and available resources to complete everything recommended in the Part 150 Study. Generally, the FAA puts a higher priority on mitigating noise for those within the highest areas of noise. Therefore, sound insulation in the areas of 65 DNL and higher are generally considered of higher priority. The Airport and FAA have placed a considerable amount of effort in the Residential Sound Insulation Program. Since the Study is now being updated, the previous measures will be evaluated and considered for future recommendations.
Question: Would you expect the monitoring done for this study to confirm the model?
Answer: Yes, it is very close. There might be some slight changes based on the data we collected around Lake Hood.
Question: It seems like this committee is gaining a lot of knowledge about noise. Is it possible to have this committee continued after the Study is complete to assist in implementation?
Answer: Yes, absolutely. A continuation of the Study Input Committee is regularly part of our recommendations in Part 150 Studies. The actual continuation will be up to the Airport to determine based on staff time available and utility of group.
Question: Will all old homes within the previous 1999 contours be insulated by 2014 (prior to the new Study being released)?
Answer: The funding for the last area of homes within the previous eligibility boundaries has been granted and those homes that applied for coverage are planned in fiscal year 2013. ANC plans to complete construction the summer of 2013 with post construction testing and financial close out extending into fiscal year 2014. Those homeowners that do not wish to apply may not be covered in the future. Airport has notified all homeowners in the RSIP boundary area about deadline.
Question: Will the contour maps show the 60 DNL?
Answer: Yes, it will show the 60 DNL, but the 65 DNL is the threshold used by the FAA for non-compatibility with residential units.
Question: Can you give us an idea of when our next meeting might be?
Answer: Yes, we are likely looking at a meeting sometime in February.
Question: Will alternatives take into account SEL?
Answer: SELs will be completed for some of the alternatives to help describe the noise environment. However, it is important to note that the 65 DNL contour is what the FAA uses to measure effects. FAA approval is based on the DNL analysis.