Aircraft Noise: A Toolkit for Managing Community Expectations (2009)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

The results of the airport noise officer survey conducted early during the data collection stage of this study sought information regarding the activity or offender most frequently complained about by the public during their conversations with airport staff about noise issues. These find- ings were verified through follow-up discussions with nearly 30 airports, users, and community advocates representing airports with a wide range of missions appropriate to the United States. Note that all results of the survey may be found in the accompanying Toolkit as Noise Complaint Characteristics The frequency of the occurrence of eight distinctly different aircraft activity effects, as cited by the survey airports, is reflected in Figure 8-1. The number of responses within each of six frequency categories was weighted to provide a measure of the relative incidence of each type of aircraft activity as a complaint or concern, as cited by the respondents. The frequencies were: “never” (0 points), “rarely” (1 point), “occasionally” (2 points), “commonly” (3 points), “frequently” (4 points), and “very frequently” (5 points). The same categories also apply to the subsequent two figures. Respondents were allowed to self-regulate their selection based on their perception of the importance of each category to the conditions at the local airport facility and its environs. • The combination of too low, too loud, and too many combined to dominate the frequency of noise complaints received by airports and were the principal source of concern within com- munities as expressed by non-airport interviewees. Noise complaints citing one of these three activities occurred more than “commonly” for the group. • Of more limited frequency (“occasionally” to “commonly”) were complaints about nighttime operations, loud landings and aircraft off expected courses. • Activity on the ground (run-ups, taxiing, reverse thrust, and ramp noise) were seldom men- tioned. This may reflect the fact that the loudest noise from these activities generally remains much closer to the airport and over more compatible land uses than the noise of aircraft in flight. Responses to questions about the types of annoyance persons cite in their noise complaints indi- cated a less specific focus on what activity was disrupted than the identification of the aircraft activ- ity that disrupted it. On average, no individual category of effect was cited more frequently than “commonly”. Figure 8-2 indicates the subject of complaint most cited as annoying to the public. • Awakening (sleep disturbance) was the most frequently cited public activity disrupted by air- craft noise, averaging only slightly less frequency than complaints about nighttime operations (see Figure 8-1). • The disruption of outdoor activity, speech and classroom activities are cited “occasionally” or less. This appears to be an inconsistency with the frequent citation of too low and too loud air- craft, the principal sources of Lmax noise levels that cause these disruptions. 8-1 119 C H A P T E R 8 Noise Abatement (Airside) Techniques

120 Aircraft Noise: A Toolkit for Managing Community Expectations Noise Complaint Type 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 Other ground noise (taxi, runway, ramp, etc.) Run-up activity Aircraft off course Landings too loud Nighttime operations Too many overflights Takeoffs too loud Aircraft too low Aircraft Activity Weighted Frequency Figure 8-1. Aircraft activity generators of noise complaints. Annoyance 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Classroom disruption Vibration and rattle effects Speech disrupted No relief (incessant exposure) Awakenings Activity Disrupted Weighted Frequency Disrupts outdoor activities Figure 8-2. Activities most frequently cited as disrupted by aircraft noise. • Concerns about vibration correlate well with the complaints about run-up activity and other ground operations. This is not unexpected because more low frequency noise – the source of most vibration and rattle effects – occurs during ground based activity. The recently published document “Aircraft Noise Effects” (145) describes in some detail the volume of literature and current understanding associated with the disruption of several differ- ent types of activity associated with aircraft noise events. As most airports canvassed for the survey were air carrier facilities with additional uses by cargo and general aviation operators, it is not surprising that commercial passenger jet activ- ity was cited most frequently as the source of the noise about which complaints were received. Figure 8-3 shows the frequency with which complaints in which each of five user groups are identified as the source of the complaint.

While noise complaints are not considered by the FAA to be a measure of compatibility in noise abatement planning, their analysis provides insights into the issues that are most important to the individuals who reside in areas exposed to aircraft noise. This chapter will review a series of oppor- tunities that the airport manager may choose to investigate with airport users and the FAA in seek- ing to moderate any adverse impacts aircraft noise may have on the airport’s neighbors. While conducting these investigations, many airports have found it helpful to involve the neighbors in seeking out various approaches to mitigate noise. By doing so, the neighbors become better aware of the constraints faced by all parties to the management of aviation conditions, and better under- stand that any improvements or resolutions to the situations they perceive to be of significant impact must be the result of a give-and-take process accepted by all parties. The remainder of this chapter provides a description of various noise abatement techniques currently in use to mitigate aircraft noise levels. These include airside measures, which are actions that the airport, air traffic control, or the aircraft operators may take to reduce the impacts of air- craft noise on populations under the routes of flight. The goal of a noise abatement action is the reduction of the number of persons exposed to environmentally significant levels. The FAA cur- rently defines that level as being 65 decibels of DNL. However, many communities around the United States are establishing additional noise level criteria for land use management that extend to areas beyond the 65 DNL level to reduce or control the introduction of newly impacted persons. The benefit or disbenefit of every noise abatement action is a function of the residential pop- ulation and number of nonresidential noise-sensitive uses that fall within the noise patterns resulting from implementation of the measure. If the population is not distributed evenly across the area affected, certain specific opportunities may be present to design noise abatement actions. When the population is broadly spread, other actions may be capable of producing the most effective results. The distribution of the noise pattern over the distributed population is the key to finding the mix of various tools for aircraft noise abatement and land use control to max- imize the reduction of noise impacts while taking into account the continuing utility of the air- port’s role as a transportation center. The application of noise abatement actions, particularly if restrictive in nature, may generate a substantial effect on airport delay and flight time, and may potentially hinder airport expansion. The next chapter will review land use management tech- niques that may be used for airport noise compatibility planning. Noise Abatement (Airside) Techniques 121 Aircraft Source Group 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 Propeller aircraft activity Helicopter operations Business jet activity Cargo jet activity Aircraft Group Weighted Frequency Commercial passenger jet activity Figure 8-3. Aircraft groups most frequently cited in noise complaints.

The subsequent paragraphs provide a short definition of the purpose of each measure, the lim- itations to its implementation, the parties responsible for its implementation and management, the general public reaction to its use and the sources of additional information about its appli- cation. Examples of how the action may be displayed to explain its effects to a public audience is provided for the most effective of these techniques. Flight Management Techniques To abate the noise of aircraft in flight, the following techniques have been used at airports across the United States in efforts to seek relief for those affected. Continuous Descent Approach (CDA) Purpose: An automated arrival procedure designed to reduce noise impacts on communities located under the approach path to a runway. The procedure is designed for aircraft to utilize a continuous descent of aircraft on a gradual slope while idling without the deployment of flaps and landing gear to reduce airframe noise. Procedure provides benefit to communities located 7-15 miles from airport and reduces fuel burn where approaching aircraft will typically fly level segments of their arrivals to sequence into the air traffic flows. These level flights may result in higher noise levels as aircraft use more thrust to remain level and have gear and/or flaps extended to maintain slow speeds. The CDA technology is new and has been implemented only at Louisville, KY, and London Heathrow Airports. CDAs are in development at several other air- ports, including Atlanta Hartsfield, Mather Field, and Los Angeles International. Limitations: CDA requires extensive research and coordination in the development of the descent profile. Procedures are designed for one or more runway ends, but usually both. It has not yet been shown to work well in environments exposed to conflicts between arriving and departing traffic, nor during peak operating periods. Procedure works very well in single operation, off-peak periods when properly designed. Implemented by: Airlines/operators with guidance from the FAA Air Traffic and Flight Standards. Airports may seek their approval if believed to be a desirable noise abatement action. Public reaction: Public experiences lesser noise levels along the full course of the approach through the absence of thrust adjustments required to maintain episodes of periodic level flight. Reaction to date on this relatively new procedure has been generally positive. The investigation of CDAs is one of the PARTNER projects undertaken by the FAA/NASA/ Transort Canada sponsored Center of Excellence. Additional information about CDAs may be found at: http://web.mit.edu/aeroastro/partner/projects/project4.html (164). Preferential Runway Use Program Purpose: This is an airport-initiated program that delineates selection procedures for the use of each runway at an airport. The runway use program can be either informal (voluntary) or for- mal (mandatory). These programs attempt to manage the number of aircraft that fly over areas along the approach and departure routes leading to or from each runway end. By doing so, the programs manage the overall noise energy present, over time, in those areas. To be effective for noise abatement, they should always be indexed to the population overflown or incorporate techniques to provide relief and respite to those persons under the preferential routes of flight. Limitations: Preferential runway use programs are driven by wind availability. When wind conditions are favorable (up to a five knot tail wind component) and runway length is adequate 122 Aircraft Noise: A Toolkit for Managing Community Expectations

for the weight of aircraft, a preferential program may result in the preferred runway’s accep- tance. Virtually all preferential use programs in the United States are voluntary and require the concurrence of the pilot in charge of the aircraft to be fully implemented. In some cases the pilot may wish to use another runway for safety purposes. When that happens, air traffic controllers will attempt to find gaps in the traffic flow that will allow the off-preference operation to take place, but the pilot may have to delay the operation to use the desired runway. Further, the most preferential runway use pattern for noise abatement may not be the most efficient pattern for operation of the airport. Consequently, preferential runway use programs may be limited to off- peak or nighttime hours to achieve their greatest application. Implemented by: FAA air traffic and airlines/operators. Airports may request the adoption of specific program measures to achieve management goals. Public reaction: When preferential runway use schemes are used to abate aircraft noise, they must take into consideration the number of persons exposed to varying levels of noise under the routes of flight. As in any case, those who are overflown will react negatively while those bene- fited by the program by not being overflown will react positively. Consequently, the correlation of noise exposure to population densities is an important consideration in the design of these programs. Public education as to the conditions and benefits of the program are also critical to their success. Example of Technique for Public Information: • Comparison of 2020 No Action and Alternative B1b Noise Exposure Pattern (165) Flight Track Modifications to Fly Over Compatible Uses Purpose: To reduce the population within noise-sensitive areas, development of specific arrival/ departure procedures may be utilized to direct aircraft while in flight. On approach or departure, use of specific departure headings, waypoints, and FMS/GPS procedures can be very helpful in keeping aircraft over the designated flight path. Flight track modification has been used to define preferred departure routes and approach courses, to separate large and small aircraft for noise abatement and to increase operational efficiency, and to specify courses for general aviation pro- peller aircraft and helicopters to assure that they do not conflict with faster jet aircraft. Limitations: Requires FAA approval in the United States of procedures, a process which can be time consuming. Some aircraft may not be properly equipped with the correct navigational instruments if the procedure uses FMS/GPS procedures. Aircraft using standard departure head- ings (“Fly heading 090 for 2 NM”) may be expected to deviate from the nominal flight path due to wind and weather conditions. When tracks are preferred or advisory (as are some helicopter routes), their use is not required. Implemented by: FAA Air Traffic is responsible for the development and management of air- craft track procedures within a controlled airspace environment. Operators are responsible within uncontrolled airspace. Airports may recommend modifications to improve noise exposure conditions. Public reaction: When flight tracks are moved to overfly compatibly used lands such as farm- land, industrial/commercial areas, transportation corridors or water, the public reaction is gen- erally positive if the traffic has been moved from over residential areas. However, if the traffic is moved from areas of dense residential population to areas of less dense residential population to achieve fewer population impacts, or if new areas of residential use are exposed to overflights beyond the compatibly used property, controversy generally will be an outcome, particularly if those newly impacted persons have not been a part of the creative process to define the courses of flight. This action has been the nexus of most airport noise litigation in the United States during 8-2 Noise Abatement (Airside) Techniques 123

the last decade. The action may also require preparation of environmental documentation if the changes result in new or increased impacts within a 65 DNL contour. Example of Technique for Public Information: • Comparative Noise Exposure of a Single Straight-out Departure Against Three Divergent Departure Routes (166) • Example of Alternative Flight Tracks Video (prepared for ACRP 02-05 project) Take Off Thrust and Flap Management Procedures Purpose: This strategy utilizes specifically designed departure climb procedures to minimize noise impacts over communities. The FAA has issued Advisory Circular 91-53A, Noise Abate- ment Departure Profile, which specifically outlines power setting and flap management tech- niques for aircraft to minimize noise for communities located either “close-in” to, or “distant” from, the airport. The National Business Aircraft Association has also designed a set of proce- dures to be used by general aviation jet aircraft. Close-in procedures are designed to reduce the noise levels over land uses close to the takeoff end of the runway by providing thrust cutbacks during climb between 1000 and 3000 feet altitude. Distant procedures provide for a thrust cut- back at a greater distance from the airport with consequent reduction of noise levels beyond 18,000 feet from the runway end. ICAO has established similar procedures. Limitations: Airlines have adopted different definitions of these procedures for their own use. Any measure that varies from the airlines standard “close-in” or “distant” procedures requires special approval from the FAA. Airlines may request carriers to use the measure that is most appropriate to the need at the airport, but it is the pilot and carrier who actually implement the measure in flight. Implemented by: Airlines/operators with guidance from airports and FAA. Public reaction: The selection of a “close-in” or “distant” departure procedure is typically transparent to the person on the ground. The noise levels generated by Stage 3 aircraft do not vary by many decibels and the location of the variance differs by aircraft type and procedure. Con- sequently, it is virtually impossible for a layman on the ground to identify what aircraft is using what procedure. Example of Technique for Public Information: • Comparative Noise Footprint of the MD-83 Using Close-in or Distant Departure Climb Profiles (167) • FAA Advisory Circular 91-53A, Noise Abatement Departure Profile (168) • NBAA material on its noise abatement program, including quiet climb and descent proce- dures at http://web.nbaa.org/public/ops/quietflying/ (169) Approach Thrust and Flap Management Procedures Purpose: This strategy utilizes specifically designed profiles to minimize noise impacts over communities. These may take the form of flap and thrust management during descent, the development of intercept altitudes that assure that aircraft turn onto final approach courses at points farther away and at higher altitudes that have been previously used, or the use of Verti- cal Navigation courses that set descent and level segments to minimize the noise produced over populated areas. The NBAA has included information on quiet flying during approach proce- 8-6 8-5 8-4 8-3 124 Aircraft Noise: A Toolkit for Managing Community Expectations

dures as part of its noise abatement tools available on-line at the address provided in the pre- ceding section. Limitations: If published as a standard procedure, the measure requires design by FAA Flight Standards and Air Traffic Organizations, with input from airlines/operators and must be devel- oped to the standards of the least capable aircraft in the poorest operating conditions to be gen- erally applied. Implemented by: Airlines/operators with guidance from the FAA Air Traffic and Flight Standards. Airports may seek their approval if believed to be a desirable noise abatement action. Public reaction: For those residing under the areas of lesser thrust or higher overflight, the reaction will be positive. Otherwise, the action is essentially transparent to area residents. Ground Operations Techniques Limit the Use of Reverse Thrust on Arrival Purpose: Jet aircraft utilize thrust reversers to help slow down just after touchdown, reduc- ing wear on the brakes and enabling shorter landing distances. The output from the aircraft engines are directed forward instead of behind the aircraft, increasing noise levels in the direc- tion of the landing. Some airports seek voluntary restriction of the use of thrust reversers and ask operators to utilize the entire runway for arrival to minimize noise impacts, particularly on areas parallel to the runway. Limitations: This is typically a voluntary program that airport operators rely on pilots to uti- lize when conditions are favorable. The measure is rarely used in poor weather or poor runway surface conditions, nor can it be used on relatively short runways when the aircraft requires a long landing distance. Implemented by: Airlines/operators, at the request of the airport with concurrence by the FAA’s Air Traffic Control management. Public reaction: In general, reverse thrust limitations are supported by those persons who live lateral to the runway and are most exposed to the increased noise levels during its use. Those who live near the far end of the runway are exposed to more taxi noise as the aircraft uses the full length of the runway to land. In a harmoniously distributed population, the use of reverse thrust is inconsequential to total noise abatement, but as with almost every noise abatement measure, the distribution of the incompatible uses around the airport drives the ability of the measure to be effective for noise reduction. Restrict Ground Run-up Activity Purpose: The airport could restrict the airlines and FBO’s to conducting ground run-up activi- ties during specified time periods and/or to a certain location on the airfield. This measure may be included in the lease agreements, and published in NOTAMs or the airport’s rules and regulations. The focus of these restrictions has historically been on aircraft undergoing engine maintenance. Limitations: On occasion, an engine that has undergone an overnight repair must be tested prior to being flown. This may result in a late night or early morning engine test run-up before an early morning flight. Restrictions on ground run-up activity frequently exempt these activi- ties or require permission from Airport Operations management prior to occurring. Implemented by: This is one of the few actions an airport may take to limit aircraft noise with- out prior approval or cooperation by the FAA. Noise Abatement (Airside) Techniques 125

Public reaction: For those who live in the airport vicinity, run-ups may be irritating because they may be long lasting and the power settings may vary from high to low. When they occur at night they become even more intrusive because the ambient levels are typically lower and they may disrupt sleep. Any limitation on the presence, time, duration, power settings, or location of run-up activity that reduces their effects on residential populations is generally seen as positive by airport neighbors. Limit Taxiing Power Purpose: An airport may request the use of single engines or idle taxi power for taxiing to and from runway ends to reduce noise along taxiway routes. Limitations: Issues have been raised about overuse of one engine for taxi operations. At busy airports, air traffic controllers may object to the potential for additional conflicts between taxi- ing and landing or departing aircraft at taxiway/runway crossings. Implemented by: Aircraft operators/pilots, at the request of the Airport with concurrence by the FAA. Public reaction: Generally positive, but may not be noticeable beyond the immediate environs of the airport. Example of technique for public information: • Ground Concept G-B (170) Facility Development Actions Runway or Taxiway Addition or Relocation Purpose: While enhancement of capacity is the primary goal of additional runways and taxi- ways, an airport may take advantage of the process by assuring that the anticipated effects of that facility are minimized by its location and alignment. The availability of a new facility may lead to additional opportunities to use preferential runway use programs that rely on a more com- patible relationship between post-construction noise patterns and underlying land uses, or allow the focusing of traffic during the most sensitive periods onto the most compatible landing and departure routes. Taxiways near population concentrations may be constructed or relocated to more remote areas to abate sideline noise effects. Limitations: Runway projects are long-term solutions that must be fully assessed under NEPA and may require years of planning, design, and construction, all at high cost, prior to being com- missioned. It is critical that once a commitment is made to pursue the new runway solution, the land uses under the approach and departure paths to that runway must be dedicated to compatible use. Implemented by: Airport, with concurrence of the FAA. Review by users and the public through the NEPA process. Public reaction: Public reaction may be mixed. As with flight track modifications, the degree of public controversy will be dependent upon the severity of adverse impacts associated with the project’s specific conditions. Displaced Threshold - Landings Purpose: A landing threshold may be located farther from the overflight end of the runway than the normal touchdown zone to seek noise abatement. This action may be implemented 8-7 126 Aircraft Noise: A Toolkit for Managing Community Expectations

to raise altitude of aircraft as they pass over areas on final approach. When arrival noise is the issue, the full runway length may be used for departures. Arriving aircraft would land at or after passing the displaced landing threshold. Displaced thresholds are more often used for obstacle clearance than noise abatement because their effectiveness in reducing noise is so small. Under a typical approach, the displacement of a runway by 1,000 feet will reduce the altitude of a landing aircraft by only about 50 feet and its accompanying noise levels by less than 1-2 decibels just beyond the clear zone, with decreasing benefits at greater distances from the runway end. On arrival only runways, that effect may reduce overall DNL by a similar amount. Limitations: Different aircraft require different runway lengths for safe operation. If the runway is displaced too far, some larger aircraft may no longer be capable of using it. The measure also may move post-landing ground noise farther to the departure end of the runway. Implemented by: Airports, with FAA approval of any changes to the airport layout plan. Public reaction: The public is rarely aware of the use of a displaced threshold unless the dis- placement is long and the runway is almost exclusively used for landings. Relocated Runway End - Takeoffs Purpose: A relocated runway end for takeoffs is the establishment of a location for the begin- ning of takeoff that is offset from the landing end of the runway. Not used nearly as often as a landing threshold displacement, this technique allows takeoffs to be initiated at greater distance from noise-sensitive uses near the landing end of the runway. The benefit that might be gained by the relocation must be balanced against the decreased safety imposed by shorter takeoff length available and lower altitudes during climb out. With a takeoff end relocated 1000 feet down the runway, a typical aircraft will be about 280 feet lower than without it. Limitations: Different aircraft require different runway lengths for safe operation. If the runway end is relocated too far, some larger aircraft may no longer be capable of using it. The measure may also noticeably increase noise levels near the overflight end of the runway. Implemented by: Airports, with FAA approval of any changes to the airport layout plan. Public Reaction: The public is rarely aware of the use of a displaced threshold unless the dis- placement is long or residences are near the runway ends. High Speed Exit Taxiways Purpose: A high speed exit is a specially designed, angled taxiway that allows arriving aircraft to leave the runway prior to coming to a full stop. Use of high-speed taxiways may diminish the noise generated on arrival at neighborhoods adjacent to the airport by allowing aircraft to exit taxiways earlier and reduce their taxi time to their parking positions at the gate or on the apron. Limitations: May be cost prohibitive for some airports to implement. Implemented by: Airport, subject to ALP approval by the FAA. Public reaction: Generally positive reactions from the public evolve from the removal of taxi- ing aircraft from the runway when the runway is adjacent to populated areas. Conversely, air- craft may apply greater levels of reverse thrust to slow enough to use a high speed exit taxiway. As the aircraft moves away from the populated areas into the core of the airport, the noise asso- ciated with the landing aircraft becomes less obtrusive. Noise Abatement (Airside) Techniques 127

Noise Barriers/Berms/Shielding Purpose: The noise impact of an aircraft on the ground is usually confined to nearby areas where the line of sight between the source and the receiver is interrupted by the barrier. An effec- tive method to mitigate this type of noise impact is through the use of sound barriers or berms. Hush houses (Ground Run-up Enclosures, GRE) are a special type of barrier that may be appro- priate in engine maintenance areas where noise events are long and often conducted at night. Strategic placement of airfield buildings has been used to interrupt the flow of noise from the source to sensitive receivers nearby. A barrier of any type does not stop the transmission of noise, but rather reflects, absorbs, or redirects parts of the noise energy. Limitations: Construction of a barrier or GRE can be cost prohibitive. Any such facility requires a considerable land footprint on the airfield to construct. Implemented by: Airport. Public reaction: The public reaction is usually positive to the noise level reduction produced by a GRE (there are documented cases where the noise level reduction at the airport boundary from a GRE is as much as 20 decibels). Lesser benefits are achieved through the provision of sound walls or earthen berms between aircraft noise sources and noise-sensitive uses. These too generally yield positive public reaction, although there may be some complaints about their structural design being unaesthetic. Example of technique for public information: • Single Event Run-up Contour – Proposed GRE Location – 727 Stage 3 (171) Restrict Apron/Gate Power Purpose: The airport may limit the airlines and other users from utilizing aircraft engines to power aircraft at the gate or at parking positions on the apron. Airports may encourage ground power units, auxiliary power units, or the installation of power and air conditioning at the gate to minimize the noise effects associated with idling aircraft. Limitations: Requires investment in auxiliary power units, ground power units, or gate elec- trical power by airport or airlines. Implemented by: Airport and aircraft operators. Public reaction: Generally positive, but may not be noticeable beyond the immediate environs of the airport. Enhanced Navigational Aids Purpose: The improvement of navigation aids may lead to better defined or predictable routes of flight, as well as enhanced safety at the airport. The introduction of point-to-point navigation systems on aircraft, coupled with ground transmitting equipment has led to the development of radar navigation system approaches and departure routes that may be crafted to more consis- tently overfly noise-compatible areas than previously used headings or vector routes. A wide array of equipment is available that may be used to allow the airport to be used in poorer weather conditions, as well as to safely navigate through the area along specific flight paths. Limitations: Requires investment in equipment. Often subject to long delays in rising on FAA priority lists for installation. Relatively long evaluation periods are required for more complex procedures. Implemented by: FAA with the assistance of the Airport and participation of the users. 8-8 128 Aircraft Noise: A Toolkit for Managing Community Expectations

Public reaction: As with measures that modify flight track locations, the results may be pos- itive or negative, dependent on the distribution of noise-sensitive uses under the resulting flight paths. Airport Access Restrictions For completeness, this section is included among the potential actions available to airports to abate aircraft noise. The airport manager in the United States is often faced with public demands to “just close the airport at night” or “make that airplane go somewhere else”. To respond to such demands, the manager must do so within the context of compliance with federal laws and reg- ulations, as well as the many grant assurances that the airport sponsor has committed to fulfill on every airport grant from the FAA. Since the passage of ANCA in 1990, no airport has received FAA approval for the implementation of a restriction on the operation of Stage 3 aircraft. Only Naples (Florida) Municipal Airport has been allowed to implement a restriction on operations by Stage 2 aircraft, and then only after successfully arguing its case in U.S. District Court. A small number of airports have actively conducted the analyses required to implement an access restric- tion under 14 CFR Part 161, but to the date of this document, no access restriction has been approved under its provisions. Prior to 1990, a number of access restrictions were implemented at airports located in envi- ronments highly sensitive to aircraft noise. At that time, these restrictions were a matter of local option. Outside the United States, restrictions on airport access remain a feasible option to abate aircraft noise. Nevertheless, the public traditionally focuses on restrictive measures in demand- ing that airports “do something” about noise levels. The following paragraphs provide an overview of the various types of access restrictions, but their implementation is subject to all Part 161 requirements. Conversely, if the measures are taken through voluntary agreement of all the existing and probable users of the airport, the actions may be implemented outside the require- ments of the regulation. Purpose: This strategy restricts, voluntarily or involuntarily, the access to the airport by pro- hibiting all or portions of its aircraft operations. In the past these restrictions have been based on cumulative impact (slot controls, noise quotas, and noise budgets), certificated noise levels (Stage 2 ban), single event noise levels, and/or time of day (curfew). They also may include the restriction of certain areas of the airfield, including runways, to specific classes or weights of aircraft. Among the access restrictions are the following types. Often they are considered in combination when implemented, e.g., a curfew on any aircraft exceeding a given noise level are denied access, while any that produce lesser noise levels are allowed to operate freely. • Aircraft type or class – A ban on operations by a given group of aircraft such as those classified as Stage 1 or Stage 2 under the categories of 14 CFR Part 36. While 14 CFR Part 161 exempts restrictions on Stage 1 aircraft from its requirements, any ban on Stage 2 aircraft must be fully evaluated and the FAA must conclude that the evaluation is adequate prior to its implementa- tion. Any restrictive action on Stage 3 or Stage 4 aircraft that affects their ability to operate at the airport must be approved by the FAA prior to implementation. Any measure that restricts access by a user group such as general aviation jet aircraft, cargo operators, helicopters, etc., may also be categorized as a type or class restriction. • Time of day – The curfew (or restriction of access by time of day) is the most recognized access restriction by the public. Prior to 1990, several were implemented and remain in force under the “grandfathering” allowances of 14 CFR Part 161. As currently implemented, curfews limit operations by type (arrivals vs. departures), by aircraft class (Stage 3 only allowed), and by noise level (prohibitions above a specific decibel level). The times of the curfew also vary – some are 10 p.m. to 7 a.m., some are 11 p.m. to 6 a.m., and some have other hourly constraints. Noise Abatement (Airside) Techniques 129

• Weight and size of aircraft – Some airports have restricted their access to those aircraft that weigh less than a fixed amount, e.g., 12,500 pounds, thereby prohibiting operations by the larger louder jet aircraft. If the airport runway is constructed to handle heavier weights, then such restrictions may be considered arbitrary and be disallowed under Part 161 provisions. • Noise level – As a surrogate to an access restriction on a class of aircraft, some measures that have been implemented cite a specific noise level that may not be exceeded. In some cases, the limitation may be on certificated noise levels for aircraft, as drawn from 14 CFR Part 36, and in other cases, the noise level may be based on measured single events, with penalties assessed against those who exceed the established levels. • Noise budget – A noise budget allocates the total noise energy present at the airport among its users, with a given amount of noise assumed for an operation by each aircraft type. Those oper- ations that take place during night and evening hours may be assigned higher values to more strictly limit such operations. Each operator is provided a “budget” and allowed to distribute that budget across its operations in any manner, so long as the total is not exceeded. The concept pro- vides incentive for the use of the quietest aircraft during daytime periods to maximize the total flights allowed. A portion of a budget is reserved for non-signatories to the budget agreement. • Operations cap – An operations cap is similar to a budget in that a limit is placed on the num- ber of flights that may occur during a given period of time, much as the budget limits the amount of noise energy. Signatories to the operations agreement pledge to limit their operations to given levels; some agreements provide exceptions from the cap for aircraft that are exceptionally quiet. • Noise Level Based Operating Fee – This strategy bases all or a portion of the landing fee upon the noisiness of the individual aircraft, thus apportioning the fees to the relative noise “cost” of the operation to the airport’s proprietor. The strategy encourages the use of quieter aircraft while producing additional revenue to offset noise induced expenses. For maximum benefit, noise fees should be used in concert with other noise abatement techniques. Instead of assessing a fee, an airport operator could reward air carriers who go to extra lengths to reduce noise generated by their aircraft by providing a discount or a reduction in land fees. (135, p. 31) • Restricted Runway Use - For noise abatement purposes, aircraft are prohibited from utilizing a specific runway for one or more types of operations. The restriction can be based on time of day or type of aircraft. For example, a runway may be maintained for propeller aircraft or arrival use only, or its use may be limited to specific wind conditions. This action has occasionally been enacted as part of an environmental mitigation program for new runways. Limitations: Among U.S. airports, with the singular exception of Naples (Florida) Municipal Airport, only those mandatory restrictions that were in place and grandfathered into law prior to the passage of ANCA remain in effect. At Naples, there is a prohibition of operations by Stage 2 business jets that was ultimately approved by the courts over the objections of the FAA under both 14 CFR Part 161 and federal grant assurance stipulations for the use of airport trust fund monies. Institution of any mandatory measure to restrict the access to an airport by Stage 3 aircraft will require the airport operator to undertake a Part 161 Study and have the measure approved by the FAA before implementation. Additionally, FAA has determined that restricting use of public air- ports is a violation of the grant assurances an airport operator agrees to when receiving federal funds for airport development. Restrictive actions voluntarily entered into to restrict access to given conditions do not require a Part 161 action. Implemented by: Airport, with review and/or approval by the FAA. Voluntary measures require agreement by the Airport and the users. Public reaction: Any action to restrict the number of operations at an airport is generally viewed favorably by those affected by aircraft noise. Conversely, restrictive actions are normally opposed by aircraft operators and the business community. 8-9 130 Aircraft Noise: A Toolkit for Managing Community Expectations

Pilot Awareness Programs Purpose: These programs are designed to provide pilots with specifics about an airport’s noise abatement program and other information, as deemed desirable. Airports often publish a handout describing the noise abatement procedures for pilots to carry in their flight manu- als, hold pilot training meetings, and develop information posters for placement in flight plan- ning rooms. Limitations: A voluntary program that requires constant updating and pilot outreach to ensure success. Implemented by: Airport. Public reaction: Awareness programs are typically transparent to the public at large, but may result in general benefits of noise reduction across a community that is positively received. Sim- ilarly, pilots are frequently supportive of pilot education and awareness programs that assist them in becoming better neighbors to noise-sensitive communities. Example of Technique for Public Information: • Phoenix Deer Valley Airport Pilot Guide (172) • Phoenix Goodyear Airport Pilot Guide (173) • Hillsborough (Oregon) Airport Pilot’s Guide (174) • Truckee Tahoe Airport Fly Quiet Pilot’s Guide (175) • Naples Municipal Airport - Recommended Fixed-Wing Arrival and Departure Procedures (56) • Naples Municipal Airport - Recommended Helicopter Arrival and Departure Procedures (57) • Naples Municipal Airport - Recommended Jet Arrival and Departure Procedures (59) • Chicago O’Hare Fly Quiet Program Aviator’s Manual online site at http://www.chicagoairports. com/cnrc/ohare/o_noise_flyquiet.shtm (176) Best Practices Based upon the effectiveness and ease of implementation associated with the various noise abatement measures, as well as the results of surveys and interviews conducted for this analysis, several techniques may be identified as best practices for achieving the greatest reduction of noise for the least cost and effort. These are: Flight Track Modification In areas of varied land use, the development of preferred flight paths over areas of compati- bly used (generally non-residential) land, particularly within three miles of the overflight end of a runway, usually provides substantial benefits to the reduction of noise impacts. The airport must assure the relocation of noise of significant levels (in FAA evaluations, above 65 DNL) from one area of population at the expense of another. This measure may be initiated by the air- port, but requires concurrence and implementation by the FAA. 8-17 8-16 8-15 8-14 8-13 8-12 8-11 8-10 Noise Abatement (Airside) Techniques 131

Voluntary Preferential Runway Use Programs Where capable of being implemented, voluntary runway use programs offer the potential for wholesale mitigation of noise impacts by changing the total number and types of overflights from areas of noise-sensitive use to other areas of compatible use. Care must be given to assure that pro- gram preferences are in line with the operating capabilities of all aircraft at the airport, as well as being carefully designed to assure that the transfer of noise exposure patterns does not adversely impact noise-sensitive uses at significant noise levels. This measure may be initiated by the airport, but requires concurrence and implementation by the FAA and users. Ground Run-Up Restrictions Where ground noise is a significant issue, the airport may implement restrictions on the time, location, and power settings used during maintenance run-up activity at an airport. It is unrea- sonable to exclude any capability to fully conduct required maintenance checks, but those that most impact surrounding land uses may be restricted to daytime hours or given locations on the airfield. Pilot Awareness Programs In light of the findings illustrated throughout this document, good communication between the airport and its stakeholders regarding the issues of noise are critical. Pilot awareness programs that convey the concerns of neighboring communities, the constraints on the airport, and the options available to its users contribute to the success of noise abatement. Many airports that have strong user awareness programs have experienced improving relationships between their pilot groups and the communities over time. Many airports that do not communicate regularly with the user group regarding conflict issues with neighbors do not overcome airport opposition. 132 Aircraft Noise: A Toolkit for Managing Community Expectations