To: All Milwaukee County Supervisors
From: James Baker, Secretary, Airport Neighbors Association, Milwaukee Re: Vote to approve/accept recommendations of Airport Noise Compatibility Study, including current and projected Noise Exposure Maps.
Dear County Supervisor, The officers and membership of the Airport Neighbors Association respectfully request your thoughtful consideration of the recently completed Part 150 Noise Compatibility study for General Mitchell
International Airport that will be presented to you for review. The Airport Neighbors Association is a group of concerned citizens that are affected daily by noise and air pollution inherent with the operation of the
states' largest airport. Over 10,000 people are subject to significant airport noise in Milwaukee County. Not all have joined our organization yet, but our membership continues to grow. As responsible citizens we believe it is our
duty to help keep our neighborhoods as livable as possible and to do whatever we can to improve them. An Airport Noise Compatibility Study (F.A.R. Part 150) is a tool designed to aid communities and airport sponsors in
dealing with airport noise in the adjacent areas by instituting a series of abatement and mitigation efforts. The Program is not mandatory, but when one is in place it reduces the airport sponsors' risk of litigation. Like any
tool, if it is used properly it can be beneficial. However, if not applied as intended, the consequences become less than desirable and the likelihood of litigation may be increased. By actual day-to-day observance and in
reviewing the data included in the study along with the proposed recommendations it is our contention that this study does not fulfill its intended purpose of reducing or mitigating airport noise in the surrounding areas as
practicable as possible. Attached are a few examples that must be seriously considered. After you review some of the examples we have provided, we are certain that you will concur with our position. We therefore request
that you, as County Supervisor, do not accept this Airport Noise Compatibility Study as the official document for submission to the F.A.A. Like many other communities across the nation and the world, we all can do a lot
better if we work together on solutions to airport noise impacts. Thank you for your consideration in this important matter. James Baker
Secretary, ANA Milwaukee, WI 53207 Attach 150 comments= = = = = = Since the future livability of some neighborhoods
could be put in jeopardy because of errors inherent to this study, I asked what could be done about this "probability." The response was, "I don't know." When I asked if I could quote these answers, "Sure," was the response. These
are not the kind of answers that lend confidence to the study at this point, nor to the ability of those conducting it, or to those who would endorse it as it is currently being presented.
At question are the results of monitoring that was used to validate the INM, in particular the results from sites to the northern, heavily populated side of the airport. The data I was
able to review via an Internet web site set up by the consultants for the GMIA study revealed some anomalies. Discovering these anomalies has raised serious concerns about the accuracy of the entire noise study, including
assumptions and predictions. The Consultants contour map showing existing conditions was generated using 2002 operations data, but incorporated noise data that were collected in 2003 – a down year. A Terminal Area
Forecast of 3%/yr was used, but 2004 had a 17% higher passenger count. 2005 was about 9% greater than 2004. 2006 appears to be slightly above 2005's count. The net gain in passenger count is much larger than the 3% TAF. Higher
passenger counts usually translate into more aircraft operations. Historical operations and passenger counts bear this out. The Consultants noise contour predictions therefore do not follow historical patterns and use unrealistic
assumptions as well as irrelevant and flawed data collection as evidenced in the examples below: EXAMPLE 1: one of the portable noise monitoring sites was located at 4401 S. Lenox. One days' worth of noise data was
collected. It showed that a total of 55 operations took place during the entire 24-hour period of June 4, 2003. Scheduled "air carrier" operations for 2003 were 177,756 – that's over 480 per day (this does not include military,
cargo, or GA operations). Even if you divided the 480 daily operations among 4 runways, you still have over 120 per day – which more than doubles what was monitored at the Lenox St. site. The runway of main concern for 4401 S.
Lenox is 1L/19R, which happens to be the preferential runway and the "noise abatement runway." After 10 p.m. and until 6 a.m. most all operations are switched to these runways. The 10 decibel nighttime penality should come into
play here, since according to the "Fleet Mix Detail" (Working Paper D, Table D7 on page 26) more operations take place at night (320) than during the day (303). Whether planes are on a north or south heading, when taking off
they will be heard at this site. The possible exception would be a landing from the south onto 1L if reverse thrust wasn't used. EXAMPLE 2: When comparing the measured Ldn at the Lenox St. monitor (M01) and the measured Ldn at
the Oklahoma Ave. monitor (NMS05) we can see an obvious disparity. Lenox St. is approximately 1500 feet west of the centerline of runway 1L/19R and recorded an Ldn of 62dB while the Oklahoma Ave. site, almost 2 miles from the
runway end, recorded a much louder Ldn of 66 dB. (Refer to Working Paper C, Figure C11 for location of noise monitoring sites.) By looking at the shape and size of the noise contour at its northern
boundaries, adjustments were apparently made. The louder site 2 miles away was not within the 65 Ldn contour, but the site 1,500 feet away was on its edge. Adjustments cannot be made to the collected data because then the data
itself would be rendered useless. The adjustments had to have been made to the INM input – thus affecting the output – that is the shape, size, and location of the noise contours. According to the "Working
Documents" ". . . the primary purpose of the measurements was not to measure DNL, but to measure the single event noise levels that can be used to validate the INM modeling." It is obvious that the INM output did not match the
measured DNL. If it had, the Oklahoma Ave. site with a measured DNL of 66 dB would be included in the 65 Ldn contour. It is not. The conclusion is that single event noise levels become less as you get closer to the airport. It is
difficult to fathom how this can be. EXAMPLE 3: Another irregularity was found for the Lenox St. site. The Consultants had monitored a single noise event from a Boeing 717 taking off on runway 1L. The event was recorded as it
passed the Lenox St. location which is approximately 1500 feet west of the extended centerline of runway 1L. An illustration was included in "Working Paper 3 ("C"), Section 1, page 45, Fig. C14" depicting a Midwest Airlines Boeing
717 (FAA Noise ID BR715) taking off on runway 1L and registering 67.1 dBA as it passed site M01. When comparing FAA's NDP database to the information shown on the illustration we find an obvious, and very serious
understatement of noise at this site. In addition, for this same operation, I have recorded noise levels of 74-80+ dBA at a distance of 2500 feet west of runway 1L. If readings from this site are in error, then others are
probably in error as well. The Consultant's prediction shows about a 6% decline in air carrier operations between 2005-2009 and, in the same period, an over 200% increase in general aviation aircraft
operations. Air carrier planes are the largest and the loudest operating at the airport. A sizable amount of these planes are hush-kitted DC9's and MD80's (over 90 per day). General aviation aircraft are generally smaller and less
noisy. Also, larger planes must follow established flight paths into and out of the airport. Smaller planes, as I have been told, can be scattered all over as soon as they are airborne. This, in effect, spreads the noise over a
much larger area. By the very nature of noise averaging, the noise from these smaller planes wouldn't be a factor. The Consultant's 2009 noise level prediction, and consequent generation of noise contours, is apparently based on
the assumption that many smaller planes will be spread out over a larger area. This speculation would, of course, reduce the future noise contour. I have not found any evidence to support this assumption. The
FAA's Area Equivalent Method may be used to determine (in square miles) the 65 DNL area. It may be used before and after the INM analysis. According to the FAA's AEM Users Guide: AEM is most often used prior to INM analysis to
determine if the INM is required for the specified type of changes, but it can also be used after initial INM evaluation in certain circumstances to refine analysis. If the AEM was run it must have provided
reason to proceed with the more expensive INM analysis. Indeed, this must have been the case because when running the AEM with the data from "Fleet Mix Detail" (Working Paper D, Table D7, page 26) the result is an area of
13.3 square miles (8,483 acres) within 65 DNL. Somehow that area was pared down to just 2,620 acres with no apparent changes to the fleet mix. CONCLUSION: For the reasons I have stated above, I believe this
study is flawed, incomplete, and inaccurate and should not be considered by Milwaukee County government as a representative example of existing and future airport noise levels. Approval of this study as it stands to date would be,
in my estimation, a travesty. The previous Part 150 study (approved by FAA in 1995) had proved to under-estimate noise levels in the northern, heavily populated side of the airport. I had written to the FAA and
County Supervisors to inform them that actual conditions did not coincide with the predictions made. In addition, Milwaukee County only saw fit to provide relief to the 70 Ldn contour plus a 1.5 Ldn "buffer" (68.5 Ldn total)
thereby placing a disproportionate noise burden on the neighborhood to the north. People in this area have been denied relief from the impact of airport noise for too long. It would appear that this study, as presented, will deny
relief again. At the beginning of this process I had stated that all I wanted was a fair and accurate assessment of airport noise levels in our community. From all that I have seen to date, this study fails to
provide that. < Use FAA Decision doc > Also, why is there no reference to monitoring sites MO6 and MO8 ? Temporary
sites numbered from 01 to 13, but numbers 6 and 8 were excluded. Were the data counted as "0" for these sites? This could explain, in part, why the contour takes such a sharp bend where these sites might have been located. (Working
Paper C, Illustration C11)
According to the consultant, sites M06 and M08 were built into the model, but were not needed as monitoring sites
and therefore, no monitoring took place at those sites. The other sites had already been assigned their numbers, and to avoid reassigning all the site numbers, M06 and M08 were simply taken out of the list.