THE FEAR OF AIRCRAFT NOISE Whereas less than half the communities which either host or neighbor New Jersey's general aviation airports reported aircraft noise as a significant problem, almost every community perceives potential airport noise (such as might result from an airport improvement) as a major problem. Historically, the only realistic complaint made about airports in New Jersey State and federal courts is their potential to produce noise (See generally Appendix G). Based on the comprehensive study of aircraft noise by the FAA and EPA which was reviewed by the Commission, as well as testimony from the leading experts in our State and our nation, the facts show that the noise levels resulting from a general aviation airport are no different than other noises produced in a modern society. However, perceptions of the airport noise problem by New Jersey's residents is apposite, and must be addressed through understanding, education, compatible zoning and community outreach. Highlights of this study and testimony are as follows: * Testimony indicated that the new generation of aircraft, especially jet aircraft, are significantly quieter than past models because the newer jet engines are high bypass turbofan engines, not the old turbojets; * If a runway is sufficiently long, a jet aircraft will be high enough by the time it reaches the end of it so that most of the noise will impact on the airport itself; * Lack of communication about the benefits and necessity of aviation tend to increase sensitivity to airport noise; * Different individuals have varying sensitivity to both actual noise and anticipated noise and humans tend to adapt to ambient noise levels; * The cumulative annual noise impact at general aviation airports is less than the community noise levels that are created by other ambient sources, particularly, motor vehicles; * In the surveys done by the Commission of those municipalities which either host or neighbor airports, noise was not the prime complaint; less than one-half of host municipalities received noise complaints from their constituents; * Federal aviation regulations set a national standard for aircraft noise, phasing out older, noisier aircraft by the year 2000. NOISE TERMINOLOGY AND NOISE EVALUATION METHOD FAR Part 150215 is based largely on a description of daily noise exposure known as the Day-Night Average Sound Level (Ldn). To appreciate Ldn it is necessary to understand several other noise metrics. It is also helpful to recognize Ldn alone does not provide an adequate basis for quantifying a specific situation. To assist reviewers in interpreting noise measures, we present below a brief introduction to relevant fundamentals of acoustics and noise terminology, and an overview of currently accepted noise and land use compatibility guidelines. Decibel, dB All sounds come from a sound source -- a musical instrument, a voice speaking, an airplane passing overhead and the like. It takes energy to produce sound. The sound energy produced by any sound source is transmitted through the air in sound waves -- tiny, quick oscillations of pressure just above and just below atmospheric pressure. These oscillations, or sound pressures impinge on the ear, creating the sound we hear. Our ears are sensitive to a wide range of sound pressures. The loudest sounds that we hear without pain have about one million times more energy than the quietest sounds we hear. But our ears are incapable of detecting small differences in these pressures. Thus, to better match how we hear this sound energy, we compress the total range of sound pressures to a more meaningful range by introducing the concept of sound pressure level. Sound pressure level is a measure of the sound pressure of a noise source relative to a standard reference pressure: either 0.0002 microbars, 0.00002 Newtons/square meter, or 20 micropascals -- all ways to express the same basic reference value. This pressure is typical of the quietest sound that a young person with good hearing is able to detect. Sound pressure levels are measured in decibels (dB). Decibels are logarithmic quantities reflecting the ratio of two pressures, where the numerator is the pressure of the sound source of interest, and the denominator is the reference pressure (the quietest sound we can hear). This logarithmic conversion of sound pressure (p) to sound pressure level (SPL) means that the quietest sound we can hear has a sound pressure level of about 0 dB, while the loudest sounds we hear without pain have sound pressure levels of about 120 dB. Most sounds in our day-to-day environment have sound pressure levels on the order of 30 to 100 dB. Because decibels are logarithmic quantities, they do not always behave like regular numbers with which we are more familiar. For example, if two sound sources that each produce 100 dB when operated separately are then operated together, they only produce 103 dB, - not the 200 dB of sound we might expect. Four equal sources operating simultaneously produce another 3 dB of noise, resulting in a total sound pressure level of 106 dB. In fact, for every doubling of the number of sources, the sound pressure level goes up another 3 dB. A tenfold increase in the number of sources makes the sound pressure level go up 10 dB. A hundredfold increase makes the level go up 20 dB, and it takes a thousand equal sources to increase the level 30 dB. It is also true that if one source is much louder than another, the two sources operating together will produce the same sound pressure level (and sound to our ears) as if the louder source were operating alone. For example, a 100 dB source plus an 80 dB source produce 100 dB of noise when operating together. The louder source "masks" the quieter one. But if the quieter source gets louder, it will have a slightly increasing effect on the total sound pressure level until, when the two sources are equal, as m entioned above, they produce a level 3 dB above the sound of either one by itself. A simple table for adding decibels from different sources is shown below. When using it for more than two sources, always start by adding the lowest two sources together first, then the higher sources in increasing order. When two decibel values differ by: Add the following amount to the higher value: 0 or 1 dB 3 dB 2 or 3 dB 2 dB 4 to 8 dB 1 dB 9 dB or more 0 dB From these basic concepts, note that a hundred 80-decibel sources will produce a combined level of 100 dB; if a single 100-dB source is then added to the group, they will produce a total sound pressure level of 103 dB. Clearly, the loudest source has the greatest effect on total noise. Conveniently, people also hear in a logarithmic fashion. Two useful rules of thumb to remember when comparing sound pressure levels are: (1) most of us perceive a 10 dB increase in the sound pressure level to be about a doubling of loudness, and (2) changes in sound pressure level of less than about 3 dB are not readily detectable outside of a laboratory environment. A-Weighted Decibel, dBA Another important characteristic of sound is its frequency, or "pitch". This is the rate of repetition of the sound pressure oscillations as they reach our ear. Formerly expressed in cycles per second, frequency is now expressed in units known as Hertz (Hz). When analyzing the total noise of any source, acousticians often break the noise into frequency components to determine how much is low-frequency noise, how much is middle-frequency noise and how much is high-frequency noise. This breakdown is important for two reasons: People react differently to low-, mid-and high-frequency noise levels. This is because our ears are better equipped to hear mid- and high- frequencies but are quite insensitive to lower frequencies. Thus, we find mid- and high frequency noise to be more annoying. High frequency noise is also more capable of producing hearing loss. Engineering solutions to a noise problem are different for different frequency ranges. Low-frequency noise is generally harder to control. The normal frequency range of hearing for most people extends from a low frequency of about 20 Hz to a high frequency of about 10,000 to 15,000 Hz. People respond to sound most readily when the predominant frequency is in the range of normal conversation, typically around 1,000 to 2,000 Hz. Psycho-acousticians have developed several filters which match this sensitivity of our ear and thus, help us to judge the annoyance of various sounds consisting of many different frequencies. The so-called "A" filter does this best for most environmental noise sources. Sound pressure levels measured through this filter are referred to as A-weighted levels (measured in A-weighted decibels, or dBA). Because of this correlation with our hearing, the A-weighted level has been adopted as the basic measure of environmental noise by the U.S. Environmental Protection Agency (EPA) and by nearly every other agency concerned with community noise throughout the United States. In particular, the Federal Aviation Administration's Part 150 requires the use of A-weighted levels when evaluating the impacts of aircraft noise on people near airports. The following table presents typical A-weighted sound levels of several common environmental sources. COMMON OUTDOOR S0UND LEVELS NOISE LEVEL dB (A) COMMON INDOOR GROUND LEVELS ROCK BAND -110- CONCORDE LANDING - 370ft 707 LANDING AT 370ft 707 TAKEOFF AT 1000ft -100- GAS LAWN MOWER AT 3ft INSIDE SUBWAY TRAIN -90- DIESEL TRUCK AT 50ft FOOD BLENDER AT3 ft NOISY URBAN DAYTIME -80- GARBAGE DISPOSAL AT 3 ft SHOUTING AT 3ft 747 TAKEOFF AT 1000 f t -70- VACUUM CLEANER AT 10 ft COMMERCIAL AREA NORMAL SPEECH AT 3ft -60- LARGE BUSINESS OFFICE QUIET URBAN DAYTIME -50- DISHWASHER NEXT ROOM QUIET URBAN NIGHTTIME -40- SMALL THEATRE, LARGE CONFERENCE ROOM (Background) QUIET SUBURBAN NIGHTTIME LIBRARY -30- QUIET RURAL NIGHTTIME BEDROOM AT NIGHT CONCERT HALL (Background) -20- RECORDING STUDIO -10- THRESHOLD OF HEARING -0- COMMON ENVIRONMENTAL SOUND LEVELS, in dBA216 In dealing with most sound sources, these A-weighted levels vary with time. For example, they rise as an aircraft approaches, they then fall again and blend into the background as the aircraft recedes into the distance, though even the background varies as birds chirp or the wind blows or a vehicle passes by. This is illustrated by the sound level of an aircraft flyover as it changes over time, e.g.: as it approaches it becomes louder; it is at its maximum as it passes overhead, and then, it diminishes as it passes on. Because of this variation, it is often convenient to describe a particular noise "event" by its maximum sound level, abbreviated as Lmax. However, the maximum level describes only one dimension of an event; it provides no information on the cumulative noise exposure generated by a sound source. In fact two events with identical maximums may produce very different total exposures. One may be of very short duration, while the other may continue for an extended period and be judged much more annoying. The next section introduces a measure that accounts for this concept of a noise "dose". Sound Exposure Level, SEL The measure of the cumulative noise exposure for a single aircraft flyover is the Sound Exposure Level, or SEL. It may be thought of as an accumulation of the sound energy over the duration of an event, where duration is defined as the time when the A-weighted sound level first exceeds a threshold level (normally just above the background or ambient noise) to the time that the sound level drops back down below the threshold. But to account for the variety of durations that occur among different noise events, the dose is normalized, or compressed, to a standard one-second duration. This "revised" dose is the SEL. It has exactly the same sound energy as the longer event, even though it is presumed to have only a one-second duration. Note that because the SEL is normalized to one second, it will almost always be larger in magnitude than the maximum A-weighted level for the event. In fact, for most aircraft overflights, the SEL is on the order of 7 to 12 dB higher than the Lmax. Also, the fact that it is a cumulative measure means that not only do louder flyovers have greater Sound Exposure Levels than do quieter ones, but also flyovers that stretch out longer in time have greater SELs than do shorter ones. With this metric, we now have a basis for comparing noise events that generally matches our impression of the sound -- the higher the SEL, the more annoying it is likely to be. Second, SEL provides a comprehensive way to describe a noise event for use in modeling noise exposure. FAR Part 150 requires that SEL be used in measuring and describing single-event noise exposure. Equivalent Sound Level, Leq We tend to think of maximum A-weighted levels and SELs as measures of the noise associated with individual events. The remaining two metrics describe longer-term cumulative noise exposure that often include many events. The first, the Equivalent Sound Level, abbreviated Leq. is a measure of the energy averaged A-weighted sound level over a particular time of interest - an hour, an eight hour school day, nighttime, or a full day. However, because the length of the period can be different depending on the time frame of interest, the applicable period should always be identified or clearly understood when discussing the metric. Such durations are often identified through a subscript, for example Leq(24). Simplistically, Leq may be thought of as a constant sound level over the period of interest that contains as much sound energy as the actual time-varying sound level with its normal peaks and valleys. It is important to recognize, however, that the two signals (the constant one and the time-varying one) would sound very different from each other if compared in real life. Also, it is important to be aware that the "average" sound level as reflected by Leq is not an arithmetic average, but a logarithmic, or "energy-averaged" sound level. Comparable to the addition of decibels, this means that higher values are given greater emphasis than lower values. For example, if the sound level is 50 dBA for 30 minutes, followed by 100 dBA for the next 30 minutes, then the Leq for the entire hour is 97 dBA -- not the 75 dBA that we might expect. Thus, loud events clearly dominate any noise environment described by the metric. In this document, Leq is normally presented for consecutive one-hour periods to illustrate how the average sound level rises and falls throughout a 24-hour period and how certain hours are significantly affected by a few loud aircraft. Day-Night Average Sound Level, Ldn. In the previous sections, we have been addressing noise measures that account for the moment-to-moment or short-term fluctuations in A-weighted levels as sound sources come and go affecting our overall noise environment. Now, the Day-Night Average Sound Level represents a culmination of the concept of noise dose as it occurs over a 24-hour period. Earlier, we illustrated the A-weighted sound level due to an aircraft flyover as it changed over time. Assume the level increases as the aircraft approaches, reaching a maximum of 85 dBA, and then decreases as the aircraft passes by. The ambient A-Level around 55 dBA is due to the background sounds that dominate after the aircraft passes. The shaded area reflects the noise dose that a listener receives during the one-minute period of the sample. The center frame of Figure 4 includes this one-minute interval within a full hour. Now the shaded area represents the noise dose over I hour, during which sixteen aircraft pass by the listener. Similarly, the bottom frame includes the one-hour interval within a full 24 hours. Here the shaded area represents the listener's noise dose over a complete day. Note that several flyovers occur at night when the background noise drops some 10 decibels, to approximately 45 dBA. An analogy is helpful here to relate the dose in this bottom frame to the Day-Night Average Sound Level. The 24-hour noise dose, shaded in the figure, is analogous to 24 hours of rain falling on a garden. The "rain dose" is the total accumulation of rain over 24 hours, just as the noise dose is the total accumulation of noise. Note that every shower increases that 24 hours' rain dose. Also, strong showers increase the dose more than light ones, and longer showers increase the dose more than shorter ones. Th e same is true for noise: (1) every aircraft increases that 24 hours' noise dose; (2) loud aircraft increase the dose more than quieter ones; and (3) aircraft flyovers that are longer in duration increase the dose more than shorter ones. One important exception to this analogy is that the Day-Night Average Sound Level treats nighttime noise differently from daytime noise. In determining Ldn, it is assumed that the A-weighted levels occurring at night (defined very specifically as 10:00 p.m. to 7:00 a.m. the next morning) are 10 decibels louder than they really are. This 10-dB penalty is applied to account for our greater sensitivity to nighttime noise, plus the fact that events at night are often more intrusive because nighttime ambient noise is less. The 10-dB penalty is illustrated in Figure 5, and its effect on the noise dose defined by Ldn is always included. 10 dB Nighttime Penalty Because the loudest and longest noise events heavily dominate any noise environment, it is possible to determine Ldn very closely by simply accounting for all of the SELs occurring during a 24-hour period and ignoring the much quieter ambient sound levels that occur between the noise events. This principle is used in all airport noise modeling. Typical Ldn values in our environment range from a low of 40 to 45 decibels in an extremely quiet, isolated location, to a high of 80 or 85 decibels very near an extremely busy highway or off the end of a runway at a busy Air Force base. More typical values would be in the range of 50 to 55 decibels for a quiet residential community and 60 to 65 decibels in an urban residential neighborhood. Figure 6 gives some examples of Ldn values measured throughout the country. Why is Ldn used to describe noise around airports? The U.S. Environmental Protection Agency identified the measure as the most appropriate means of evaluating airport noise based on the following considerations:217 1. The measure should be applicable to the evaluation of pervasive long-term noise in various defined areas and under various conditions over long periods of time. 2. The measure should correlate well with known effects of the noise environment and on individuals and the public. 3. The measure should be simple, practical and accurate. In principal, it should be useful for planning as well as for enforcement or monitoring purposes. 4. The required measurement equipment, with standard characteristics, should be commercially available. 5. The measure should be closely related to existing methods currently in use. 6. The single measure of noise at a given location should be predictable, within an acceptable tolerance, from knowledge of the physical events producing the noise. The measure should lend itself to small, simple monitors, which can be left unattended in public areas for long periods of time. Most other public agencies dealing with noise exposure have formally adopted Ldn Part 150 requires that Ldn be used in describing cumulative noise exposure and in identifying aircraft noise and land use compatibility issues. QUALITATIVE DESCRIPTIONS Ldn DAY- NIGHT SOUND LEVEL DECIBELS OUTDOOR LOCATIONS -90- -87.5- LOS ANGELES- 3rd FLOOR APARTMENT NEXT TO FREEWAY -86- LOS ANGELES - 3/4 MILE FROM TOUCH DOWN AT LAX -85- CITY NOISE (DOWNTOWN MAJOR METROPOLIS) -81- -80- -78.5- LOS ANGELES- DOWNTOWN WITH SOME CONSTRUCTION ACTIVITY -78- HARLEM- 2nd FLOOR APARTMENT -75- -74- VERY NOISY -73- RESIDENTIAL -70- NOISY URBAN -68- BOSTON- ROW HOUSING ON MAJOR AVENUE -65- URBAN -63- -62.5- WATTS - 8 MILES FROM TOUCH DOWN AT MAJOR AIRPORT -62- NEWPORT - 3.5 MILES FROM TAKEOFF AT SMALL AIRPORT -60- LOS ANGELES- OLD RESIDENTIAL AREA SUBURBAN -55- SMALL TOWN & QUIET SUBURBAN -53- -51- SMALL TOWN CUL-DE-SAC -50- SAN DIEGO- WOODED RESIDENTIAL -48- -45- -44- CALIFORNIA -TOMATO FIELD ON FARM -40- Examples of Outdoor Day-Night Sound Level (Ldn) in dB, measured in various U.S. locations. Ldn can be measured or estimated. Measurements are practical only for obtaining Ldn values for relatively limited numbers of points, and, in the absence of a permanently installed monitoring system, only for relatively short time periods. Most airport noise studies utilize computer-generated Ldn estimates depicted in terms of equal-exposure noise contours (much as topographic maps have contours of equal elevation). Part 150 requires that the 65, 70 and 75 dB contours be modeled and depicted. Noise and Land Use Compatibility Guidelines. Ldn estimates have two principal uses in a Part 150 study: (1) to provide a basis for comparing existing noise conditions to the effects of noise abatement procedures and/or forecast changes in airport activity; and (2) to provide a quantitative basis for identifying potential noise impacts. Both of these functions require the application of objective criteria for evaluating noise impacts. Government agencies dealing with environmental noise have devoted a great deal of attention to this problem, and have proposed many different sets of noise/land use compatibility guidelines. In addition to establishing Ldn as the official cumulative noise exposure metric for use in airport noise analyses, Part 150 provides the FAA's recommended guidelines for noise/land use compatibility evaluation. These guidelines are shown in Table 1. These guidelines represent a compilation of the results of extensive scientific research into noise-related activity interference and attitudinal response. However, reviewers of Ldn contours should recognize the highly subjective nature of response to noise, and the special circumstances that can either increase or decrease individuals' tolerance. For example, a high non-aircraft background or "ambient" noise level can reduce the significance of aircraft noise, such as in areas constantly exposed to relatively high levels of traffic noise. Alternatively, residents of areas with unusually low background levels may find relatively low levels of aircraft noise annoying. Expectation and experience may also affect response. People often get used to a level of noise exposure that guidelines indicate may be unacceptable, and changes in exposure may generate response that is far greater than that which the guidelines might suggest. The cumulative nature of Ldn means that the same level of noise exposure can be achieved in an essentially infinite number of ways. For example, a reduction in a small number of relatively noisy operations may be counterbalanced by a much greater increase in relatively quiet flights, with no net change in Ldn. Residents of the area may be highly irritated by the increased frequency of operations, despite the seeming maintenance of the noise status quo. With these cautions in mind, the Part 150 guidelines can be applied to the Ldn contours to identify the potential types, degrees and locations of incompatibility. Measurement of the land areas involved can provide a quantitative measure of impact that allows a comparison of the effects of existing or forecast operations. EFFECTS OF NOISE ON PEOPLE IN AN URBAN RESIDENTIAL ENVIRONMENT Effects Hearing Loss Speech Interference Annoyance Average Community Reaction General Community Attitude Towards Area Indoor Outdoor Day-Night Average Sound Level in Decibels Qualitative Description % Sentence Intelligibility Distance in Meters for 95% Sentence Intelligibility % of Population Highly Annoyed 75 and above May Begin to Occur 98% 0.5 37% Very Severe Noise is likely to be the most important of all adverse aspects of the community environment. 70 Will Not Occur 99% 0.9 25% Severe Noise is one of the most important adverse aspects of the community environment. 65 Will Not Occur 100% 1.5 15% Significant Noise is one of the important adverse aspects of the community environment. 60 Will Not Occur 100% 2.0 9% Moderate Noise may be considered an adverse aspect of the community environment. 55 and below Will Not Occur 100% 3.5 4% None to Slight Noise considered no more important than various other environmental factors. Source: Airport Compatibility Guidelines, Texas Aeronautics Commission, January, 1986. Dr. R. John Hansman, of the Aeronautical Engineering Department of the Massachusetts Institute of Technology (MIT), came before the Commission to present testimony and exhibits respecting the matter of aircraft noise. Dr. Hansman has been awarded a Bachelor's Degree in Physics from Cornell University, a Masters Degree in Physics and a Ph.D. in physics, meteorology, aeronautics and electrical engineering from MIT and is currently on the faculty as a tenured professor at MIT. The standard for tenure at MIT is simply, the candidate must be the most knowledgeable person in the world in his field.218 Dr. Hansman was allowed to testify as an expert. Dr. Hansman testified that the new generation of aircraft, especially jet aircraft, is significantly quieter than the jet aircraft with which we first became familiar.219 The Global Positioning System (GPS), the new satellite based navigation system, has the potential to reduce noise even further by making possible steeper approaches and accurate curved ground tracks as aircraft return to land.220 He stated that if a runway is sufficiently long, a jet aircraft will be high enough by the time it reaches the departure end of it that most of the noise impact will be on the airport itself.221 The federal government has a comprehensive formula regulating the noise an aircraft is permitted to emit in FAR Part 36.222 Dr. Hansman explained that the newer jet aircraft are quieter because the newer jet engines are high bypass turbofan engines, not the old turbojets. In order to increase both the thrust and the fuel efficiency of engines, the designers have developed these high bypass engines, which put 5-6 times as much air through a circumferential fan as goes through the core of the jet. The high bypass air mixes with (and muffles) the jet exhaust so that there is much less jet noise, much less of the traditional "sharp rumbling"223 associated with older jet aircraft.224 Dr. Hansman testified that MIT was commissioned by the National Aeronautics and Space Administration (NASA) to study flight procedures to reduce community noise enabled by GPS and other flight guidance technologies. He was in charge of that study. We all know that the common decibel rating for noise, dBA, is a physical measurement of the pressure change of noise adjusted for the physiology of the ear in terms of how well the ear can hear it.225 However, the dBA scale, as a physical measurement, does not account for the fact that no two people have the same thought process or the same level of sensitivity.226 In order to determine how a human is impacted, many studies have been conducted to study peoples' response to noise and to create measurement scales, which are weighted accordingly.227 What has been discovered in these noise sensitivity studies is that humans tend to adapt to the ambient noise level, within reason. "There may be a church near your house that has a bell that goes off every 15 minutes. After a while, you don't hear it."228 Similarly, noise caused by boats, trains and aircraft can all be canceled out if they are not too loud. Dr. Hansman stated that prior studies had revealed several findings respecting the psychology of hearing aircraft noise and gave examples: 1. If an aircraft flies over two people with equal hearing ability, one will "hear" the aircraft and the other will not. 2. The same person, who does not "hear" an aircraft fly overhead in the bustle of the day, will hear it in the restfulness of the night. 3. The same person who is not bothered by the sound of aircraft noise in his day to day life, may be bothered by it while visiting a quiet setting. Dr. Hansman explained that while some individuals are able to cancel out (become oblivious) to aircraft noise, others are hypersensitive to it. Someone who becomes hypersensitive to a particular noise can never cancel it out.229 He stated that there are certain hypersensitive individuals who will never be able to ignore or "cancel out" noise from an aircraft. This will continue to be true when the aircraft noise is significantly reduced, even after the point when it drops below the level of the ambient noise. The hypersensitive individual's ear can follow it (stay tuned to it) into the background. Dr. Hansman also testified that airports across the country can name specific individuals who complain on a regular basis. They consider them hypersensitive, as no complaints are filed by persons actually experiencing higher levels of aircraft noise.230 It is suspected they become hypersensitive for psychological reasons rather than for the actual loudness of the noise. For example, they are already annoyed for another reason. They believe their noise complaints are not being acted upon by a public servant. They harbor a personal dislike for a particular aircraft owner or airport owner. The Commission also received testimony from Mr. Henry Young, a general aviation consultant since 1974, and head of his own firm, Young Environmental Sciences, since 1984. Mr. Young explained the issue of noise sensitivity by saying that "aircraft, because of their prominence, tend to stand out, both in the sense of visually standing out and in the sense that their noise is delivered in short but intense bursts."231 Even though some people may tend to psychologically focus on aircraft noise, Mr. Young's statistical analysis of the noise monitoring data from Teterboro Airport, the busiest corporate general aviation airport in the world, consistently shows that "the cumulative annual noise impact at these locations from aircraft is less than the community noise levels that are created by other ambient sources, particularly, motor vehicles."232 According to Mr. Young, a factor that increases the sensitivity to aircraft noise is the lack of communication and a lack of understanding of the benefits and necessity of aviation.233 "It would not be surprising, for example, in a rural community that did not have a trusting and open relationship with airport management to be as much as ten times more sensitive [to noise] than they would be if they felt that whatever they were experiencing was being adequately addressed from a regulatory standpoint and was being minimized so that whatever disruption occurred is the absolute least that they should have to tolerate."234 In addition to there being different levels of sensitivity to actual or existing noise, Mr. Young testified that there can also be varying sensitivities or perceptions of anticipated noise that would be associated with an airport expansion. As an example, he brought with him a poster from the Internet regarding the Branchburg-Readington public meeting on the Solberg Airport expansion. This poster was described in the previous chapter and warns of airline flights and other exaggerated fears. Mr. Young commented: "The amount of adverse reaction that is being generated to that proposal is entirely out of proportion to the amount of noise that is generated by that facility. . . 235 Their expectations are significantly different than the realities that would logically be expected to be created. In other words, the problem would not be significantly enlarged. They simply perceive that any enlargement, no matter how slight, is utterly unwanted. Thus, they have an expectation of a problem which is unlikely to materialize."236 Mr. Young also reviewed the history of federal noise regulation that began in 1967 with Part 36 of the Federal Aviation Regulations.237 The regulations began with phasing out the Stage I jet aircraft (the original and loudest ones), followed by a program to phase out the Stage II aircraft (the ones which emitted less noise), and now, today, it requires that after the year 2000 all aircraft must be Stage III aircraft (the least noisy aircraft).238 In the Aviation Safety and Capacity Act of 1990, Congress accelerated the phase out of Stage II aircraft by the year 2000. After that, all aircraft will have to meet Stage III requirements and older aircraft will either have to be modified or retired.239 Since the Act set a uniform national standard for aircraft noise, it prohibited local, facility-specific regulations.240 Federal law and regulations preempt state or municipal aircraft noise regulation. Mr. Young stated that "most general aviation aircraft, with the exception of older business jet types, will meet or exceed the levels associated with Stage III."241 He added, "you will generally find at smaller airports that the level of cumulative noise which occurs does not significantly go off the facility."242 With the federal preemption of aircraft noise regulations (see generally Appendix G), this Commission obviously cannot make a recommendation for any State or municipal noise guidelines. The Commission does find that the noise issue is subjective and emotional. The federal standard is an indication of the importance of aviation to interstate commerce and the national transportation system. With aircraft being able to leap time zones, much less states and municipalities, it would be a regulatory maze for the aviation industry if it had to track and comply with thousands of different noise regulations across this country. Potentially, it could strangle the entire system. What this profusion of standards and units of measurement would mean to an the aircraft operator was once eloquently expressed by Frank Kolk, then vice president of American Airlines: "Imagine driving your automobile from California with a speed limit of 60 mph into Arizona with a speed limit of 45 knots, into New Mexico with a speed limit of 110 kilometers per hour, and on into Texas with a speed limit of 150 ft. per second. None of the speed limits are comparable, of course."243 As each year's production is added to the fleet, and as each year's attrition is deleted from the fleet, the percentage of the fleet that meets FAR Part 36, Stage III noise standards has increased. For example, by the end of 1976, there had been 2,500 business jets manufactured worldwide, of which only 20 percent met Stage III standards. By the end of 1986, the fleet has grown to more than 3,700 aircraft, adjusting for attrition. Most of the new jets were stage III compliant, increasing the percentage of Stage III aircraft to 55 percent. There were nearly 8,500 business jets operating at the beginning of 1990; of these 66 percent met Stage III. But adjusting for attrition, at least 75 percent of the fleet met Stage III standards at the start of 1997. The "hush kit" programs now in place will increase this to 85 percent in the near future.244 All aircraft must meet stage III standards by the year 2,000. It is interesting to note that in the surveys done by this Commission of those municipalities, which either host or neighbor airports, noise was not the primary or predominant complaint. When asked whether they were receiving complaints from their constituents about aircraft overflights, only 46.6 percent of the host municipalities responded "yes" and, then, an equal number, 46.6 percent, responded "no". Interestingly, approximately half that number, 26.6 percent of those municipalities which host airports, were receiving complaints about aircraft noise at night. When host municipalities were asked whether the airport was a good neighbor, 46.6 percent responded "yes." Forty percent responded "no". When asked why the airport was not a good neighbor, the major responses had nothing to do with aircraft noise (but rather said "expand the airport", "communicate", and "cooperate with community", "industrial park"). When asked what the airport could do to become a better neighbor, only 6.6 percent of the respondents said "reduce noise." Administrators in communities which neighbor airports, had fewer concerns about aircraft noise. When it was suggested that the majority of the people in their community were concerned about aircraft noise from the neighboring township, 57 percent either did not know or disagreed. Forty-three percent agreed in varying degree. When it was asked how many complaints they received monthly about aircraft noise, 59 percent said five or more per month. Twenty-one percent received one or less of such complaints. When considered in their totality, these facts reveal that noise is not really the major problem created by the general aviation airport. Perhaps it is, that as aircraft have become quieter and we have become accustomed to aircraft noise, it does not bother us as much as we believe it does. Clearly, when an airport proposes to make improvements, which are popularly perceived as inviting business jet aircraft, the negative reaction is logarithmically greater than it is for the noise (sometimes of business jet aircraft) they experience everyday. Footnotes: 215 See Appendix G, notes 64-72 and accompanying text. "FAA Part 150 encourages airport owners and operators to prepare Noise Exposure Maps (NEM) which are scaled geographic depictions of a particular airport, the measured noise contours emanating from it, and the land use compatibility of real property surrounding the airport. 'The main objectives of the Part 150 program are to reduce existing noncompatible uses around an airport and to prevent the introduction of any additional noncompatible uses.'" Id. at 15 [Citations omitted]. 216 Source: Harris, A.S., and Miller, R-1-, Airport Noise Seminars, documentation prepared for the Airports Division, Southern Region, Federal Aviation Administration, November 1977. 217 "Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety," U. S. EPA Report No. 550/9-74-004, September 1974. 218 NJGASC, 4/30/96 page 2. 219 NJGASC, 4/30/96, pages 32,41. 220 NJGASC, 4/30/96, pages 23, 25-26. 221 NJGASC, 4/30/96, pages 39-41. 222 NJGASC, 4/30/96, pages 20-21. 223 NJGASC, 4/30/96, page 31. 224 NJGASC, 4/30/96, pages 32-33. 225 NJGASC, 4/30/96, pages 9-10. 226 NJGASC, 4/30/96, page 14. 227 NJGASC, 4/30/96, pages 14-15. 228 NJGASC, 4/30/96, page 11. 229 NJGASC, 4/30/96, page 11. 230 NJGASC, 4/30/96, page 35. 231 NJGASC, 5/28/96, page 19. 232 NJGASC, 5/28/96, page 19. 233 NJGASC, 5/28/96, pages 12-13. 234 NJGASC, 5/28/96, page 14. 235 NJGASC, 5/28/96, page 10. 236 NJGASC, 5/28/96, page 23. 237 NJGASC, 5/28/96, page 4. 238 NJGASC, 5/28/96, page 9. 239 NJGASC, 5/28/96, page 32. 240 NJGASC, 5/28/96, page 32. 241 NJGASC, 5/28/96, page 10. 242 NJGASC, 5/28/96, page 21. 243 Report of the Aviation Advisory Commission (January 1973) p 15. This Commission was enabled by the US Congress (Public Law 91-258-1970) with a mandate to "formulate recommendations [to the President and the Congress] concerning future airport requirements and the National Airport System Plan ... surrounding land uses, ground access, airways, [etc.] ...." 244 Report of Grubb Associates of Chicago in Business & Commercial Aviation (September, 1997).