Paul Raveling
2737 Carnelian Circle
El Dorado Hills, CA 95762
Paul.Raveling@sierrafoot.org    (916) 933-5826

May 26, 2008
El Dorado Hills Community Services District
    Board of Directors
    Cc:  El Dorado County Board of Supervisors,
            City of Folsom,
            Sacramento County Airport System
            Selected local news media
 1021 Harvard Way
El Dorado Hills, CA 95762

Re:  Resolution 2007-28, regarding EIR preparation for the Mather Airport Master Plan



Dear CSD directors,

Materials forwarded with this letter are notes and comments by me as a private individual, they are not from either of the two organizations that I sometimes represent as a director. These materials are also being posted to my personal web site, www.sierrafoot.org.

I support the objective of the CSD resolution, to include El Dorado Hills in environmental studies for the Mather Airport Master Plan. However, the resolution contains many errors of fact and assumptions that are at best questionable. I recommend that CSD reassess the issues involving jet noise and issue an amended resolution correcting the errors in 2007-28 and setting a more cooperative and less combative tone than is apparent in the earlier resolution. An annotated copy of the resolution and related materials is attached to this letter.

My earlier comments to the Sacramento County Airport System, from November 25, 2007, are best summarized by my opening paragraph:

I recommend that your environmental studies for the Mather Master Plan include updated jet freighter noise measurements and approach path tracking for the El Dorado Hills and Folsom area, with emphasis on early morning single-event noise around 4 a.m. Noise monitoring on a continuing basis would be appropriate, with monitoring in EDH to be arranged through cooperative agreement with the County of El Dorado.

It may be more appropriate for the El Dorado Hills Community Services District to become the primary agent for El Dorado Hills participation, rather than the County of El Dorado. However, you need to seriously study this issue.

Recently I have undertaken in-depth research into the question of noise due to air carrier cargo operations. I have repeatedly observed freighter approachs from a vantage point on Ridgeview Drive, directly beneath the ILS approach path. This is nearly at the maximum terrain elevation of 1,126 feet on the western ridge of El Dorado Hills. I followed up by correlating the approaches that I observed with flight traks through the WebTrak service. I used WebTrak to additionally examine at least 200 freighter approaches to date, as well as to sample all flight activity during all 24 hours in a small sample of days. The latter exercise showed that business jets and possibly Air Force T-38s are more likely to be heard than freighters.

My most important observations were that freighter overflights are less noisy than vehicle traffic passing on the street. This correlates well with SCAS noise measurements showing an average maximum sound level (Lmax) of 65 to 66 dB for freighter overflights at a nearby site on the same ridge. Data published by SCAS from measurements in 2004 showed a maximum Lmax of 73.4 dB and 85% of all freighter overflights between Lmax = 62.2 and 71.0 dB. In reviewing large larg numbers of flight tracks to date I have identified only one which could possibly have produced about 80 dB. That was at a point over part of Serrano on the eastern ridge and the flight had captured the glide slope and resumed a normal descent by the time it reached the western ridge. On the whole, freighter ILS approaches show a high degree of precision navigation both horizontally and vertically. Arrival at the Initial Approach Fix usually occurs within 100 feet of 6,500 feet altitude (MSL). Passage over my observation point on the EDH west ridge is even more consistent, on the ILS glide slope at 3,900 feet MSL and passing at a throttle setting at or near flight idle.

The CSD and other local agencies who are concerned with noise issues have a real need to determine whether complaints are due to production of noise or perception of noise. Within the possibilities of perception, agencies need to determine whether we have a community problem, a subcommunity problem, or a problem appropriate only for attention by individuals with unusual sensitivity.

An additional issue is that I have found is erroneous public perception. I've spoken with a fair number of people who now erroneously assume that if they hear jet noise it must be a freighter, and some who are now conditioned to assume that if they hear jet noise it must be a problem. The clearest examples are some who express such concerns about departure noise:  There are no air carrier cargo departures that overfly El Dorado Hills. News coverage of complaints about freighter noise are conditioning many residents to accept belief in incorrect and conjectural arguments driven by bias toward a particular conclusion. On the other hand I have also spoken with residents who live under the ILS approach path and say there is no freighter noise problem.

As El Dorado Hills grows our noise issue increase, but they stem mainly from surface traffic. Let's keep our attention tuned as closely as possible to objective reality.

                                                                                       Sincerely,
 
 

                                                                                       Paul Raveling