Part 150 PAC April 20, 2017

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Part 150 KSQL
PAC  (Planning Advisory Committee) Meeting 4/20/17

Calmtheskies is a member of the Planning Advisory Committee, (PAC).  I will summarize my impressions from the meetings.  Better and more thorough information can be found on the website for this Part 150 study I have been asked questions about the study, and I have listed the questions as FAQS.   You may submit additional questions to the website

If you would like to be added to our mailing list about San Carlos Airport Part 150 Noise Study issues, you can add your e-mail to the County’s GovDelivery Service (cut and paste into browser if the direct link does not work) and select “San Carlos Airport – FAA Part 150 Noise Study” from the list of available topics. Once you submit your email address, you will get to a page with the list of Subscription Topics. Scroll down to Public Works and you will see the airport
The Part 150 Noise Compatibility Study, which is funded through Airport funds and by a grant from the FAA, is designed to evaluate the existing and future compatibility of the Airport with neighboring areas, as well as examine new or different noise abatement techniques and land use measures which may prove to be beneficial.

What is a Part 150 study?  Their words:   In January 2017, work began on a voluntary Part 150 Noise Compatibility Study.  A Part 150 Study provides the community with information it can use to address compatibility issues.  Noise compatibility planning and noise abatement techniques developed with this study will be used to prevent future noise impacts and to address existing concerns about noise.  The study explores the full range of options available so that local officials can determine how the airport can meet the increasing demands placed on it, while at the same time fulfilling the role of being a good neighbor through noise abatement measures.

My take on it:  This is primarily a land use study.   There is unlikely to be any noise relief from the Surf Air flights and the other Pilatus planes and operators that fly low and loud over our homes.

What is the final product of the study? Their words: A Noise Compatibility Program which is intended to promote aircraft noise control and land use compatibility. The principal objectives of the Noise Compatibility Program are to:  Identify the impacts of current and projected noise levels in the airport area using FAA software. Propose strategies to reduce the impacts of aircraft noise through changes in aircraft operations or airport facilities.  In undeveloped areas where aircraft noise is projected to remain, encourage zoning designations compatible with the noise and operation of an airport, such as agricultural, commercial, or industrial.

My take on it:  Final product will be a Noise Impact Contour, a map that will show noise levels around the airport.  They produce an ALUCP, an Airport Land Use Comprehensive Plan.  If you think you hear a lot of KSQL plane noise, and if this study agrees, you might get some insulation.   I think the final product primarily helps the County plan land use so as to avoid residences in areas of noise.

When will the study be completed?  The Noise Compatibility Program Update is now underway and is expected to be completed in 18 to 24 months.  Information about the study and its preliminary findings will be made available to the PAC and the general public periodically through public meetings, news releases, and on the project website:

Are sound meters placed in neighborhoods? Yes, but their use is limited and their contribution minimal.  Part 150 follows specified procedures.   Specific data points are entered, such as air speed, time of day, airplane type, runway, date, number of operations, how high they fly, wind, terrain, etc.   The type of plane enables the study to use FAA sound ratings for that plane.  Sound meters in yards gather too much extraneous data to be useful.  They only serve as a backup source for comparison to the data if desired.

What is CNEL? CNEL is a sound metric used to measure and evaluate noise.  Community Noise Equivalent Level.  It is a 24 hour time weighted energy average noise level with decibel penalties for events occurring after 7 pm until 7 am.  CNEL is California’s equivalent to the federal DNL (Day-Night Average Sound Level).  Many feel that these metrics do not reflect the adverse impacts of airplane noise on residents.  The 65 decibel threshold is too high.  The averaging of the noise events results in a low overall noise level and “does not capture the effects of noise on affected residents.”  This language is from a letter from various members of Congress (the Quiet Skies Caucus) in July 2015.
Read the full letter >>

My take on it:  don’t expect the sound metric to show any excessive noise over your house.