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umptionst <br /> 9.A. - Page 110 <br /> (AAD)activity profile is computed by adding all aircraft operations occurring during the course <br /> of a year and dividing the result by 365. As such,AAD does not reflect activities on any one <br /> specific day,but represents average conditions as they occur during the course of the year. The <br /> evening weighting is the only difference between CNEL and DNL. For purposes of aircraft noise <br /> analysis in the State of California,the FAA recognizes the use of CNEL, and the metric is used to <br /> assess potential significant impacts. <br /> A.4 The Integrated Noise Model <br /> The Integrated Noise Model(INM)is the FAA-approved, industry-accepted, state-of-the-art tool <br /> for determining the total effect of aircraft noise exposure at and around airports. The INM has <br /> been the FAA's standard tool for determining the predicted noise impact in the vicinity of airports <br /> since 1978, and is recognized by the State of California as the appropriate tool for aircraft noise <br /> assessments. The INM uses runway and flight track information, operation levels distributed by <br /> time of day, aircraft fleet mix, and aircraft profiles as inputs. The INM calculates noise exposure <br /> levels at a series of"noise grids", and produces noise exposure contours based on the grid results, <br /> for a variety of noise metrics including CNEL,DNL, Lmax,Leq, and SEL. As described below, <br /> for this ALUCP the INM was used to calculate CNEL contours for existing conditions (2013) and <br /> 20-year future conditions (2035). <br /> A.5 Existing Conditions Noise Exposure — San Carlos Airport <br /> Noise exposure contours were developed for San Carlos Airport using the latest version of the <br /> FAA's Integrated Noise Model(INM),Version 7.0d. The following sections summarize the <br /> data/inputs used to develop the existing conditions(2013) CNEL contours presented in Chapter 3 <br /> of this white paper. <br /> A.5.1■Annual-AverageNDay Operationstby'AircraftvTypev <br /> For CNEL aircraft noise exposure calculations, aircraft operations associated with the annual- <br /> average day are used in the INM. The number of annual operations by each INM aircraft type is <br /> divided by 365 to arrive at the annual-average day(AAD)level. This representation of airport <br /> activity does not reflect any particular day,but gives an accurate picture of the character of <br /> operations throughout the year.Use of AAD is required by the FAA for aircraft noise modeling. <br /> 2013 AAD operations by aircraft type, operation type(i.e., arrival, departure,touch-and-go), and <br /> time of day are summarized in Tableoo-2ott the end of this Appendix. Touch-and-go operations <br /> in the INM consist of an arrival and a departure. The number of touch-and-go operations at San <br /> Carlos Airport in 2013 was calculated by dividing local operations by two. <br /> A.5.2vTimew ■Dayv <br /> As noted previously,the CNEL metric applies different weighting penalties to aircraft operations <br /> during the evening or nighttime hours. Therefore,the average daily numbers of operations by <br /> SanfCarlosfAirportV A-6 ESAfAirportsf/130753f <br /> ALUCPfWhitefPape/ Junef2014f <br />