Aircraft Noise 101
San Francisco International Airport April 2019 Table of Contents
1. About SFO • Airport and Aircraft Noise • General Aviation Sources • Mission • Fly Quiet Program • Noise Metrics • Historical Firsts 4. Airspace Modernization • Noise Modeling • Accomplishments • Residential Sound Insulation – NextGen • Role and Responsibilities Program and New Initiative • Northern California Metroplex • Stakeholders • Balanced Approach to • NextGen Components and Phases • SFO Airport Community Managing Noise of Flight Roundtable • Noise Law • Implementational Changes • Aircraft Noise Management Structure 3. SFO Aircraft Noise 5. Resources • Aircraft Noise Management Abatement Procedures 6. Glossary System • Major Arrival and Departure 2. Noise Fundamentals Routes • Noise and Annoyance • On-Airport Noise Restrictions • Measuring Sound Levels • Nighttime Preferential Runway Use Mission
San Francisco Aircraft Noise Abatement office serves as a Although San Francisco International Airport economic link between the public, airline operators, and federal footprint in the Bay Area is vast, we recognize responsibility agencies. Our goal is to provide clear and accessible as environmental stewards. SFO’s mission “to provide information to our communities. We ensure that SFO meets exceptional airport in service to our communities” includes or exceeds all Federal and State aircraft noise regulations addressing aircraft noise impacts. and that flights operate as quietly as possible. Historical Firsts Noise Compatibility Program Study. In 1983 SFO was the first airport in the country to prepare a Federal Aviation Regulation (FAR) Part 150 Noise Compatibility Study, allowing SFO to receive noise compatibility funding. This translated into the Residential Sound Insulation Program which reduced aircraft noise in more than 15,000 homes, 8 churches and 7 schools.
Early phase out of noisier aircraft in the U.S. Prior to any federal regulations, SFO formed its own program to phase out older, noisier aircraft by the year 2000. Subsequently, the Federal Aviation Administration (FAA) adopted a similar nationwide policy to completely phase out older and louder airplanes, known as Stage 2 aircraft.
First to track aircraft with an Aircraft Noise Management System. SFO installed its first noise monitoring system in 1975. Since that time the system has been regularly updated to incorporate the latest in technology. Accomplishments Nationally recognized collaborative community process. Since successful in working with the local governmental agencies to keep the late 1970s, SFO has been a participant and supporter of the the area along the shoreline north of the Airport an industrial zone. Airport Community Roundtable, a public forum for aircraft noise reduction. The Roundtable develops an annual work plan to Community Noise Exposure Level. SFO has been very establish new noise abatement and mitigation programs and successful in reducing the size of the 65 dB CNEL noise impact monitors existing ones. SFO also provides both financial and staff boundary. Back in 1976, over 35,000 people lived within the 65 support to the Roundtable. decibel CNEL contour. Today, through the Residential Sound Insulation Program, residential dwellings located inside high noise Land use compatibility zoning. For over 30 years SFO has areas are now compatible with airport operations. worked with surrounding communities to help preserve compatible land uses in areas under the flight paths. For example, SFO was Role and Responsibilities Owned and operated by City and County of San Francisco. SFO As a local entity, we are also the closest point of contact with the serves primarily as landlord in the broadest definition of the term. The community and are generally in charge of creating, explaining and airport holds leases with tenants including airlines, concessions and implementing noise abatement programs. Thus, the airport is airport related businesses, and in such capacity can control when and responsible for monitoring noise levels and reporting them to the where certain operations occur on its property. public, as well as taking remedial actions such as soundproofing homes and schools in high noise areas. The airport may advocate for From a noise abatement perspective, this means that an airport can certain noise abatement flight procedures to reduce local impacts, but these must be approved by the FAA. Airports also actively encourages reasonably regulate activities such as engine maintenance run- FAA and Congress to provide noise mitigation funds, and to create ups by controlling where they take place and instituting certain restrictions at night. and enforce stricter noise abatement standards for the aircraft manufacturers. Stakeholders
Federal Agencies Elected Officials
Airlines Aviation Industry
Airport Communities Community Roundtable
SFO Airport Community Roundtable Meeting SFO Airport Community Roundtable One of the oldest and most respected airport community forums. The Roundtable monitors a performance-based noise mitigation program implemented by airport staff, interprets community concerns and attempts to achieve noise mitigation through a cooperative sharing of authority among the aviation industry, the FAA, SFO management and local government.
• Voluntary, informal committee of appointed and Membership elected officials from the City and County of San • Cities and Towns in San Mateo County (18) Francisco, the County of San Mateo, and the cities and • County of San Mateo towns in the County of San Mateo. • City/County of San Francisco • Created by a Memorandum of Understanding; no local, state, or federal mandate to exist • Board of Supervisors • Airport Commission • Forum for the public to address the responsible parties for noise issues related to aircraft operations at SFO • San Francisco Mayor’s Office • Considered by the FAA and General Accounting Office to • City/County Association of Governments of San Mateo be a national model for intergovernmental cooperation to County (C/CAG) Airport Land Use Committee (ALUC) address aircraft noise issues Advisory Members Brief History FAA • 1981 Creation of the roundtable consisting of two counties Airline Representatives and nine cities • 1982 First Work Plan Introduced • 1997-1998 Nine additional cities joined the Roundtable • 2001 Adoption of the SFO “Fly Quiet” Program Meetings • 5 to 6 meetings per year, held first Wednesday of the meeting month • Meetings are recorded; written meeting summaries are prepared by Roundtable staff; meeting summaries are available to the public • All meetings are open to the public • Special meetings and workshops as needed Annual Work Program • Address key issues / identify responsible agencies • Schedule items for discussion / action • Allocate resources • Work Program items are recommended by the Roundtable’s Work Program Subcommittee Funding
• provided by its members; majority of annual funding provided by Airport • Staff support (Part Time Planner, SFO Airport Noise Abatement Staff, Technical Consultant)
SFO Cities C/CAG County SFO Aircraft Noise Management Structure
Quieter Planes Quieter Procedures Advocating for future quieter Developing noise mitigation procedures technology to ensure that residents that benefit communities share in the benefits.
Working with Communities Land-Use Planning and Open and transparent communication, Mitigation educating and leading to a constructive Reducing environmental impact dialog. Understanding community through compatible land use and concerns and providing information. planning through Residential Sound Insulation Program
Noise Program Monitor existing flight operations and follow up with the airlines if there are deviations from the program, Fly Quiet Program. Aircraft Noise Management System
Input Analysis Output
Air Traffic Control Audio Weather Data Airport Director’s Report Single Integrated Real-Time Flight Operations Fly Quiet Program Reports database Community Noise Reports Aircraft Noise Monitoring Report Noise Monitor Levels Website Information Automated Contour Generation Noise Fundamentals What is NOISE?
Noise is unwanted sound and it is subjective. For some a distant aircraft can be a pleasant sound while for others it is considered noise. Even sounds that are pleasant at one volume can become noise to us as they get louder. Noise, then, has both an objective, physical component; as well as a subjective component that takes account of a person's individual perception, or reaction, to a sound. We can not measure perception of noise, we can only measure sound levels. Noise Levels vs Annoyance We can relate sound levels to percent annoyed and activity interference.
Percentage of persons highly annoyed by aircraft, road, and rail traffic noises. The curves were derived for adults on the basis of surveys (26 for aircraft noise, 19 for road noise, and 8 for railways noise) distributed over 11 countries. Source: Munzel T.,Gori T.,Babisch W.,Basnel M. Cardiovascular Effects of Environmental Noise Exposure; License: CC BY-NC 3.0 Measuring Sound Levels
Sound pressure is any variation pressure that human ear can detect
Decibel (dB) is a ratio of measured sound pressure to a reference sound pressure. In sound, decibels measure a scale from the threshold of human hearing, 0 dB, upward towards the threshold of pain, about 120-140dB. Because decibels are such a small measure, they are computed logarithmically and cannot be added arithmetically. • Outside of the laboratory a change of 3 dB is barely perceptible. • A 6dB increase requires dB increase requires four times four times the sound energy. • An increase of ten dB is perceived by human ears as a doubling of noise.
Addition of Decibels • 100dB + 100dB = 103 dB • 100dB + 100dB + 100dB + 100dB + 100dB + 100dB = 106 dB • 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB + 100dB = 110 dB Source: Noise Level Chart, Boomspeaker.com Weighting
A-Weighted Decibel (dBA) adjust sound pressure weighting towards the frequency range of human hearing. The FAA and State of the California has adopted the A-weighted sound level for environmental analysis.
Rarely, but at times C-weighting is used to capture ground-based back blast noise behind departing aircraft. This generally low frequency sound is impulsive and may induce secondary effects, such as shaking, rattling or vibrations. These secondary effects can cause additional annoyance and complaints. Source: Lindosland What effects our level of annoyance?
Length, • Longer and repetitive noise Frequency Time of Day exposure likely results in higher annoyance Emotions • Attitude toward noise • A sudden loud aircraft can be a sudden surprise that makes one Physical feel without control Environment • At night annoyance is higher when we are awoken • Background noise at night is lower Control Predictability than during the day Airport Noise Sources
Aircraft Departures Engine Run-Ups Running APU
Aircraft Arrivals Reverse Thrust Aircraft Idling/Taxiing 10 9
8 12
11
7 3 6 4 2 1 5
Aircraft Noise Sources
1. Landing Gear 6. Turbine/Fan Core 11.Slats 2. Engine Nacelle 7. Flaps 12.Wingtip Vortices 3. Fan Blades 8. Speed Brakes 4. Thrust Reversers 9. Fuselage 5. Jet/Fan Exhaust 10.APU What it means to “Fly Dirty”
Slats extend the wing forward Flaps extend back and down, Air brakes increase drag without adding lift affecting lift Spoilers rise up from the wing, braking and increasing rate of descent Aircraft noise levels have, despite what some may feel, been decreasing
Number of Seats
Year Listen to the examples of aircraft noise
Clips are intended to give non-experts a general feeling of what over-flights would sound and look like. Copyright NATS 2013 How does noise get into my home?
Chimney
Walls Windows Cracks Doors Description of the Sound of a Single Event (SEL, Lmax and duration)
Noise Metrics Lmax (maximum sound level)
Lmax Area in which The peak noise level reached energy is 10 dB compressed to by a single aircraft event. Below obtain SEL Lmax SEL – Single Event Noise Exposure Level - The noise exposure level of a single aircraft Weighted Sound Level Level Sound (dB) Weighted -
event measured over the time between the A initial and final points when the noise level Time exceeds a predetermined threshold. It is Rise Fall (seconds) important to distinguish single event noise Duration levels from cumulative noise levels such as CNEL. Single event noise level numbers are generally higher than CNEL numbers, because CNEL represents an average noise level over a period of time, usually a year. Community Noise Equivalent Level (CNEL)
CNEL is used by the State of California (Title 21 of the California Code of Regulations, Airport Noise Standards) to describe land use compatibility with respect to aircraft noise exposure. The acceptable level of aircraft noise for people living in the vicinity of an airport is 65 decibel A-Weighted (dBA) CNEL. It is a measurement of noise averaged over a 24-hour period. In addition, each aircraft noise event occurring between evening (7pm-10pm) has penalty of 4.77dBA, and night (10pm-7am) has a penalty of 10dBA. This penalty is to account for the higher sensitivity to noise in the night time and the expected nighttime decrease of background noise levels. The CNEL metric is unique to California in that it adds a penalty calculation for evening and night operations. Other states use the Day-Night Average Level (DNL). Source: Federal Aviation Administration Measuring Sound Levels Permanent and Portable Noise Monitoring
Measurements accurately tell us the sound levels at a specific site for a specific time period. Measurements are not predictive, but can show historical trends and are useful in validating the output of a noise contour model.
Monitor
Microphone and tripod
Short-term, using portable monitoring equipment. Long-term using permanent monitors. Noise Modeling
Aircraft Noise Monitoring System consists of 29 Permanent Noise Monitors.
Modeling shows us sound levels over a broad geographic area as well as at specific location for a specific time period. Modeling can produce a historical record or it can be predictive by showing expected trends. Noise Exposure Map (NEM) is a map of the airport and vicinity that shows areas of average noise exposure over a period of one year. CNEL metric is used in creating noise Residential Sound Insulation Program
If incompatible land uses exist the airport requires a variance. A variance requires a plan to reduce incompatible land use. SFO’s plan included: • Noise Monitoring System • Sound Insulation Program • Noise Abatement Procedures • Roundtable Work Program 15,200 • Runway Reconfiguration Study 8 Churches Homes SFO was the first major airport not requiring a variance through its noise insulation program and has reduced noise impact area by this standard to zero. 7 Schools Since 1983, more than 15,200 properties have been treated in Daly City, Millbrae, Pacifica, San Bruno, South San Francisco and unincorporated areas in the County of San Mateo. The total program expenditure to date amounts to more than $192 million. The program is funded through a Sound Insulation Program Expenditure: $192 million combination of FAA and airport funds distributed by the Airport. Replacement and Second Chance Noise Insulation Initiative Led by the Airport and first of its kind in the United States, the initiative intents to provide acoustical improvements to qualifying residential properties that meet certain eligibility requirements. These improvements are offered at no cost to eligible property owners.
This initiative has two main components, as follows:
• Second Chance Initiative: This initiative gives a second chance to participate in the Noise Insulation Program (NIP) to owners that did not participate in previous phases of the NIP. • Replacement Initiative: This initiative provides repair or replacement of eligible acoustical improvements to residential properties that were insulated in previous phases of the NIP, where the improvements have failed.
To be considered, the property must be located inside a specific noise boundary corresponding to the area where the average daily aircraft noise level is equal to or greater than 65 decibels. This contour is designated as the 65-dB CNEL noise contour in the SFO Noise Exposure Map, as accepted by the FAA. Future phases of this Initiative may consider properties outside this noise contour on a case by case basis, depending on the dwelling’s proximity to the 65-dB contour and availability of funds.
Initiative website Balanced Approach
Although SFO is now quieter than it’s been anytime Land Use since 1970s, and the number of people exposed to Noise Source Planning and significant aircraft noise has decreased, community Reduction Management concerns regarding aircraft noise have been increasing.
Our social responsibility is to continue working with all Balanced Approach to Reducing Aircraft Noise stakeholders to reduce the aircraft noise impacts in the communities surrounding the airport. Noise Operating Abatement Restrictions Procedures Learn more here: ICAO Balanced Approach to Aircraft Noise Management Aviation Noise Law
Federal Preemption • Local airports have no legal authority to reject flight path changes mandated by the FAA. • The FAA has “exclusive sovereignty of airspace in the United States.” 49 U.S.C. § 40103(a). • The FAA “is authorized and directed to prescribe air traffic rules and regulations governing the flight of aircraft . . . .” 49 U.S.C. § 40103(b)(1). • The FAA “has full control over aircraft noise, pre-empting state and local control.” City of Burbank v. Lockheed Air Terminal Inc., 411 U.S. 624, 633 (1973).
Local Regulation Limited • States and local governments “may not enact or enforce a law, regulation, or other provision having the force and effect of law related to a price, route, or service of an air carrier that may provide air transportation . . . .” 49 U.S.C. § 41713.
Airport Noise and Capacity Act of 1990 (ANCA) • Stage 2 Aircraft Phase-Out by 2000 • Part 161- Airports to seek public and FAA comment before implementing restrictions • The restrictions cannot be discriminatory, unreasonable, nor unduly burdensome to interstate commerce, nor can they impede the FAA's execution of the national Stage 3 transition. • Part 150 Funding through Airport Improvement Plan and passenger facility charges • ANCA does not affect any airport noise or access restrictions in effect before November 5, 1990 • Noise Compatibility Program SFO Noise Abatement Procedures
Combine elements of:
City and Part 150 County of Noise San Francisco Compatibility Noise Plan Resolutions and consist of primarily voluntary runway use and departure/arrival Keep in mind that safety Airport FAA Air procedures ALWAYS takes Community Traffic precedence over noise Roundtable Control abatement procedures. Major Arrival and Departure Routes Wind direction and speed have a direct impact on the direction of arrivals and departures. For safety reasons aircraft need to land and take-off into the wind.
West Plan 95% Southeast Plan 5% Use of water facing runways whenever wind and weather conditions allow
10L/10R 1L/1R
Over the Bay Flights
19L/ 19R
28L/28R
San Francisco International Airport Airfield layout SFO Air Traffic Flow Patterns Wind Rose Map
West Plan West Plan “Straight 28” Southeast Plan Wind blows predominantly out of the Wind blows predominantly out of the Wind blows predominantly out of the West. Aircraft are arriving 28L/R and West, North West at speeds greater South, Southeast. Aircraft are departing 1L/R. than the maximum crosswind arriving on 19 L/R and departing 10 component for 1L/R departures L/R. therefore aircraft arrive and depart 28 L/R
Wind rose graphically displays wind speed and direction at the airport over time. Wind directions are presented cardinally (north, east, south, west) and their immediate directions (16 spokes). Each “spoke” shows how often the wind blows from each direction and how often the wind blows at each pre-defined wind speed bins for each wind direction (shown by color bands). Wind is measured in mph. On-Airport Noise Restrictions
Engine Run-Up Restrictions are restricted during nighttime hours. Daytime engine run ups cannot exceed five minutes in duration and are conducted in the area facing the Bay.
Ground Run Up Monitoring System consist of motion detection cameras and noise monitoring stations. This allows SFO staff to detect when ground run up activity occurs at unauthorized airfield areas. Taxiway Victor at Lima
Taxiway Echo at Auxiliary Power Unit (APU) Lima
APU is a small jet engine located in the rear of Taxiway Charlie an aircraft; it is used when the aircraft is on the at Whiskey ground to power heating and air conditioning systems. Operators are encouraged to use 400Hz ground power and preconditioned air whenever practicable. APU usage is limited to 30 minutes. Nighttime Preferential Runway Use (10pm-7am) 1. RWY 10 L/R Maximize flights over water and minimize Departures flights over land and populated areas between 1:00 a.m. and 6:00 a.m.
2. RWY 28 L/R Airport activity levels are lower late at night, Departures (NIITE) and it is feasible to use water-facing departure procedures more frequently than it would be possible during the day. 3. Number 3 preference General Aviation Operations
Airspace Restrictions Aircraft over the City of San Francisco must stay Helicopters outside of (below) both San Francisco International • Stay over industrial areas, highways or over Airport and Oakland International Airport's respective water Class B airspace, unless aircraft receive approval before entering the airspace from the FAA. • Limit the amount of time they hover and stay in a Commercial air traffic with airport destinations in the given area. Class B airspace takes priority over helicopters • Many overflights are primarily due to news transitioning the airspace. During busy times, events, traffic watch/reporting, air ambulances or whenever the FAA is unable to approve transitions in law enforcement flights and do not require a timely manner; helicopters must fly below or approval prior to their operation, unlike scheduled around the Class B airspace. air carriers. Fly Quiet Program View Fly Quiet Video Airport Community Roundtable initiative implemented by the SFO Aircraft Noise Abatement Office Encourage individual airlines to operate as quietly as possible at SFO. The program promotes a participatory approach in complying with noise abatement procedures and objectives by grading an airline’s performance and by making the scores available to the public via newsletters, publications, and public meetings. Fleet Noise Quality
• Awards points for quiet aircraft
• Compares SFO to national fleet mix Noise Exceedance Rating
• Measures noise at each of 28 remote monitoring sites
• Maximum decibel levels are set for day and night events at all noise monitoring sites Nighttime Preferential Runway Use Shoreline Departure
• Depart RWY 10 L/R over water between 1:00 - 6:00 • Noise Abatement Procedure for Runway 28 AM • Keep aircraft east of Highway 101 • Depart RWY 28 L/R over land and turn over water • Visual procedure • Depart RWY 28 L/R and climb over land Gap Departure Rating
• Higher is Better • Compare similar aircraft on similar routes • Criteria based on historical data Foster City Fly Quiet Rating
• 2 points for a good arrival
• 1 point for a marginal arrival
• 0 for a poor arrival
• Limited to jet airlines arriving between 11 p.m. and 6 a.m. on Runway 28L/R Awards
• Airlines responded favorably • Want to improve • Scores going up - noise going down
Each year airlines are given awards for: • Quietest Flying Airline • Most Improved Airline • Chairman’s Award Airspace Modernization - NextGen Goals: Improve safety and efficiency, increase airspace capacity and reduce delays.
NextGen is a congressionally mandated initiative to modernize the U.S. Air Transportation System between 2012 and 2025. In November 2014, Federal Aviation Administration implemented new tools in the Bay Area (Northern California Metroplex) to help with the modernization of our transportation system. The changes incorporate policies, procedures, and technologies. Most notable is the shift toward satellite based navigation and advanced communications. This change was needed in order to increase flight efficiency of the National Airspace System (NAS), reduce environmental footprint, and have more precise, predictable flight paths which increase safety.
Suite of NexGen Solutions Metroplex Metroplex is a metropolitan area with several major airports and complex airspace. Congestion and other limiting factors create deficiencies across the entire National Airspace System (NAS). A key NextGen goal is to safely improve the efficiency of NAS by increasing efficiencies in metropolitan areas.
SFO is a part of the Northern California Metroplex, which uses NextGen technologies that allow ways to de-conflict airspace and expand efficiency gains that would otherwise extend to other areas in the NAS. Northern California airspace is complex, with traffic from numerous major airports. All arrivals and departures are interconnected and interdependent.
Source: Federal Aviation Administration NextGen Phases of Flight Optimization of Airspace and Procedures in the Metroplex NextGen Components: RNAV/RNP Moving to Performance-Based Navigation
View the Bay Area flight track density image on the next slide for comparison between Conventional Routes (ground-based navigation and RNAV (satellite based navigation) routes. Implementational Changes NextGen is an FAA project. The role of the airport is to communicate this change and the benefits of the system to the communities and work together with the FAA, community and other stakeholders to reduce aircraft noise impacts that might have emerged with the change.
October 2014 Pre-NextGen October 2017 Post-NextGen
Major arrival and departure flight routes are still present, and the majority of the newly introduced procedures are direct overlays of the old ones, nevertheless there were some changes. In general, routes have increased concentration, there is less dispersion, and there were some lateral/vertical changes to the routes. Aircraft are now able to fly more precise flight paths with satellite based navigation. These implemented procedures require a certain level of accuracy that can be compared to a car staying within its highway lane. Community Impact SFO Aircraft Noise Abatement has received an increased number of inquiries and noise reports from areas as far as 80 miles from SFO. Prior to Metroplex implementation SFO averaged 14,000 annual complaints. After Metroplex noise reports have skyrocketed to over 2 million annual reports from about 10,000 individuals. Aircraft Noise Resources
• FAA Noise Quest • SFO Community Roundtable Noise 101 • Airport Noise and Access Restrictions • Northern California (NorCal) Environmental Assessment • FAA NextGen • National Transportation Noise Map • Aircraft Noise Overflight Video Glossary A communications and/or radar, visual signaling and other devices to provide safe, expeditious movement of air traffic. ADS-B - Automatic Dependent Surveillance - Broadcast uses ground based antennas and in-aircraft displays to alert pilots to the position of other aircraft relative to Avionics – Airborne navigation, communications, and data display equipment required for operation under specific air traffic control procedures. their flight path. ADS-B is a key element of NextGen. Altitude MSL –Aircraft altitude measured in feet above mean sea level. AGL – Above Ground Level, is a height measured with respect to the ground. Air Carrier - A commercial airline with published schedules operating at least five round B trips per week. Backblast - Low frequency noise and high velocity air generated by jet engines on takeoff. Air Taxi – An aircraft certificated for commercial service available for hire on demand. Base Leg – A flight path at right angles to the landing runway. The base leg normally ALP - Airport Layout Plan – The official, FAA approved map of an airport’s facilities. extends from the downwind leg Ambient Noise Level – The existing background noise level characteristic of an to the intersection of the extended runway centerline. environment. Approach Lights – High intensity lights located along the approach path at the end of an C instrument runway. Approach lights aid the pilot in transitioning from instrument flight CDA - Continuous Descent Approach, see also OPD. conditions to visual conditions at the end of an instrument approach. Center – See ARTCC. APU - Auxiliary Power Unit – A self-contained generator in an aircraft that produces power Cloud Ceiling – The height above the earth’s surface of the lowest layer of clouds that is for ground operations of the electrical and ventilation systems and for starting the engines. reported as “broken” or “overcast.” Is reported in feet AGL. Arrival – The act of landing at an airport. CNEL – Community Noise Equivalent Level - A noise metric required by the California Arrival Procedure - A series of directions on a published approach plate or from air traffic Airport Noise Standards for use by airport proprietors to measure aircraft noise levels. control personnel, using fixes and procedures, to guide an aircraft from the enroute CNEL includes an additional weighting for each event occurring during the evening environment to an airport for landing. (7:00pm – 9:59pm) and nighttime (10:00pm – 6:59am) periods to account for increased Arrival Stream – A flow of aircraft that are following similar arrival procedures. sensitivity to noise during these periods. Evening events are treated as though there were three and nighttime events are treated as though there were ten. This results in a 4.77 and ARTCC – Air Route Traffic Control Center - A facility providing air traffic control to aircraft 10 decibel penalty for operations occurring in the evening and nighttime periods, on an IFR flight plan within controlled airspace and principally during the respectively. enroute phase of flight. CNEL Contour - The "map" of noise exposure around an airport as expressed using the ATC - Air Traffic Control - The control of aircraft traffic, in the vicinity of airports from CNEL metric. A CNEL contour is computed using the FAA-approved Integrated Noise control towers, and in the airways between airports from control centers. Model (INM), which calculates the aircraft noise exposure near an airport. ATCT– Air Traffic Control Tower - A central operations tower in the terminal air traffic Commuter Airline – Operator of small aircraft (maximum size of 30 seats) performing control system with an associated IFR room if radar equipped, using air/ground scheduled (maximum size of 30 seats) performing service between two or more points. DNL metric. A DNL contour is computed using the FAA-approved Integrated Noise Model D (INM), which calculates the aircraft noise exposure near an airport. D Decibel (dB) - In sound, decibels measure a scale from the threshold of human hearing, Downwind Leg – A flight path parallel to the landing runway in the direction opposite the 0 dB, upward towards the threshold of pain, about 120-140 dB. Because decibels are such landing direction. a small measure, they are computed logarithmically and cannot be added arithmetically. An increase of ten dB is perceived by human ears as a doubling of noise. Duration - The length of time in seconds that a noise event lasts. Duration is usually measured in time above a specific noise threshold. Delay Vectors - When ATC assigns an aircraft a heading that takes it off course, before bringing it back on course. Delay vectors may be used for many reasons such as for E aircraft traffic or to create spacing between aircraft. Enroute – The portion of a flight between departure and arrival terminal areas. dBA - A-weighted decibels adjust sound pressure towards the frequency range of human Exceedance— Whenever an aircraft overflight produces a noise level higher than the hearing. maximum decibel value established for a particular monitoring site, the noise threshold is dBC - C-weighted decibels adjust sound pressure towards the low frequency end of the surpassed and a noise exceedance occurs. An exceedance may take place during spectrum. Although less consistent with human hearing than A- weighting, dBC can be approach, takeoff, or possibly during departure ground roll before lifting off. used to consider the impacts of certain low frequency operations. Decision Height – The height at which a decision must be made during an instrument F approach either to continue the approach or to execute a missed approach. FAA - The Federal Aviation Administration is the agency responsible for aircraft safety, Departure – The act of an aircraft taking off from an airport. movement and controls. FAA also administers grants for noise mitigation projects and approves certain aviation studies including FAR Part 150 studies, Environmental Departure Procedure – A published IFR departure procedure describing specific criteria Assessments, Environmental studies, Environmental Assessments, Environ Impact for climb, routing, and communications for a specific runway at an airport. Statements, and Airport Layout Plans. Displaced Threshold - A threshold that is located at a point on the runway other than the FAR – Federal Aviation Regulations are the rules and regulations, which govern the physical beginning. Aircraft can begin departure roll before the threshold, but cannot land operation of aircraft, airways, and airmen. before it. FAR Part 36 – A Federal Aviation Regulation defining maximum noise emissions for DME - Distance Measuring Equipment - Equipment (airborne and ground) used to aircraft. measure, in nautical miles, a slant range distance of an aircraft from the DME navigational aid. FAR Part 91 – A Federal Aviation Regulation governing the phase out of Stage 1 and 2 aircraft as defined under FAR Part 36. DNL - Day/Night Average Sound Level - The daily average noise metric in which that noise occurring between 10:00 p.m. and 7:00 a.m. is penalized by 10 dB. DNL is often expressedFAR Part 150 – A Federal Aviation Regulation governing noise and land use compatibility as the annual-average noise level. studies and programs. DNL Contour - The "map" of noise exposure around an airport as expressed using the Ground Effect – The excess attenuation attributed to absorption or reflection of noise by F manmade or natural features on the ground surface. FAR Part 161 – A Federal Aviation Regulation governing aircraft noise and access Ground Track – is the path an aircraft would follow on the ground if its airborne flight path restrictions. were plotted on the ground the terrain. Final Approach – The last leg in an aircraft’s approach to landing, when the aircraft is lined up with the runway and is descending for landing. H Fix – A geographical position determined by visual references to the surface, by reference High Speed Exit Taxiway – A taxiway designed and provided with lighting or marking to to one or more Navaids, or by other navigational methods. define the path of aircraft traveling at high speed from the runway center to a point on the Fleet Mix – The mix or differing aircraft types operated at a particular airport or by an center of the taxiway. airline. I Flight Plan – Specific information related to the intended flight of an aircraft. A flight plan is filed with a Flight Service Station or Air Traffic Control facility. IDP - Instrument Departure Procedure - An aeronautical chart designed to expedite clearance delivery and to facilitate transition between takeoff and enroute operations. IDPs FMS – Flight Management System - a specialized computer system in an aircraft that were formerly known as SIDs or Standard Instrument Departure Procedures. automates a number of in-flight tasks, which reduces flight crew workload and improves the precision of the procedures being flown. IFR - Instrument Flight Rules -Rules and regulations established by the FAA to govern flight under conditions in which flight by visual reference is not safe. G ILS - Instrument Landing System – A precision instrument approach system which GA - General Aviation – Civil aviation excluding air carriers, commercial operators and normally consists of a localizer, glide slope, outer marker, middle marker, and approach military aircraft. lights. GAP Departure – An aircraft departure via Runways 28 at San Francisco International IMC – Instrument Meteorological Conditions - Weather conditions expressed in terms Airport to the west over San Bruno, South San Francisco, Daly City, and Pacifica. of visibility, distance from clouds, and cloud ceilings during which all aircraft are required to Glide Slope – Generally a 3-degree angle of approach to a runway established by means operate using instrument flight rules. of airborne instruments during instrument approaches, or visual ground aids for the visual Instrument Approach – A series of predetermined maneuvers for the orderly transfer of portion of an instrument approach and landing. an aircraft under instrument flight conditions from the beginning of the initial approach to a Go-Around - an aborted landing of an aircraft that is on final approach. landing, or to a point from which a landing may be made visually. GPS - Global Positioning System – A satellite based radio positioning, navigation, and J time-transfer system. GPU - Ground Power Unit – A source of power, generally from the terminals, for aircraft K to use while their engines are off to power the electrical and ventilation systems on the Knots – A measure of speed used in aerial navigation. One knot is equal to one nautical aircraft. mile per hour (100 knots = 115 miles per hour). NDB – Non-Directional Beacon - Signal that can be read by pilots of aircraft with L direction finding equipment. Used to determine bearing and can “home” in or track to or Load Factor – The percentage of seats occupied in an aircraft. Lmax – The peak noise from the desired point. level reached by a single aircraft event. NEM – Noise Exposure Map – A FAR Part 150 requirement prepared by airports to depict Localizer – A navigational aid that consists of a directional pattern of radio waves noise contours. NEMs also take into account potential land use changes around airports. modulated by two signals which, when receding with equal intensity, are displayed by NextGen – The Next Generation of the national air transportation system. NextGen compatible airborne equipment as an “on-course” indication, and when received in unequal represents the movement from ground-based navigation aids to satellite-based navigation. intensity are displayed as an “off-course” indication. NMS – See RMS Noise Contour – See CNEL and DNL Contour. LDA – Localizer Type Directional Aid – A facility of comparable utility and accuracy to a Non-Precision Approach Procedure – A standard instrument approach procedure in localizer, but not part of a complete ILS and not aligned with the runway. which no electronic glide slope is provided. M O Middle Marker - A beacon that defines a point along the glide slope of an ILS, normally OAPM - Optimization of Airspace and Procedures in the Metroplex – This is a part of located at or near the point of decision height. the FAA’s Next Generation of air traffic control plans for 21 areas with multiple airports in Missed Approach Procedure – A procedure used to redirect a landing aircraft back the United States. around to attempt another landing. This may be due to visual contact not established at Offset ILS – Offset Parallel Runways – Staggered runways having centerlines that are authorized minimums or instructions from air traffic control, or for other reasons. parallel. N Operation – A take-off, departure or overflight of an aircraft. Every flight requires at least two operations, a take-off and landing. NAS – National Airspace System - The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas; aeronautical charts, Outer Marker – An ILS navigation facility in the terminal area navigation system located information and services; rules, regulations and procedures, technical information, four to seven miles from the runways edge on the extended centerline indicating the manpower and material. beginning of final approach. Nautical Mile – A measure of distance used in air and sea navigation. One nautical mile is Overflight – Aircraft whose flights originate or terminate outside the metropolitan area that equal to the length of one minute of latitude along the earth’s equator. The nautical mile transit the airspace without landing. was officially set as 6076.115 feet. (100 nautical miles = 115 statute miles) OPD – Optimized Profile Descent – An efficient, reduced power method by which aircraft Navaid – Navigational Aid. approach airports for landing. It is designed to reduce level off segments during descent, reducing fuel consumption and noise. NCT – Northern California TRACON – The air traffic control facility that guides aircraft into and out of San Francisco Bay Area airspace. P generate data used in preparation of the airport’s Noise Exposure Map. RNAV – Area Navigation - A method of IFR navigation that allows an aircraft to choose PASSUR System – Passive Surveillance Receiver - A system capable of collecting and any course within a network of navigation beacons, rather than navigating directly to and plotting radar tracks of individual aircraft in flight by passively receiving transponder from the beacons. This can conserve flight distance, reduce congestion, and allow flights signals. into airports without beacons. PAPI – Precision Approach Path Indicator - An airport lighting facility in the terminal RNP – Required Navigation Performance - A type of performance-based navigation area used under VFR conditions. It is a single row of two to four lights, radiating high (PBN) that allows an aircraft to fly a specific path between two 3- dimensionally defined intensity red or white beams to indicate whether the pilot is above or below the required points in space. RNAV and RNP systems are fundamentally similar. The key difference runway approach path. between them is the requirement for on- board performance monitoring and alerting. A PBN –Performance Based Navigation - Area navigation based on performance navigation specification that includes a requirement for on-board navigation performance requirements for aircraft operating along an IFR route, on an instrument approach monitoring and alerting is referred to as an RNP specification. One not having such a procedure or in a designated airspace. requirement is referred to as an RNAV specification. Preferential Runways - The most desirable runways from a noise abatement perspective Run-up – A procedure used to test aircraft engines after maintenance to ensure safe to be assigned whenever safety, weather, and operational efficiency permits. operation prior to returning the aircraft to service. The power settings tested range from Precision Approach Procedure – A standard instrument approach procedure in which an idle to full power and may vary in duration. electronic glide slope is provided, such as an ILS. GPS precision approaches may be Run-up Locations - Specified areas on the airfield where scheduled run-ups may occur. provided in the future. These locations are sited, so as to produce minimum noise impact in surrounding PRM – Precision Runway Monitoring – A system of highresolution monitors for air traffic neighborhoods. controllers to use in landing aircraft on parallel runways separated by less than 4,300’. Runway – A long strip of land or water used by aircraft to land on or to take off from. Q S R Sequencing Process – Procedure in which air traffic is merged into a single flow, and/or in which adequate separation is maintained between aircraft. Radar Vectoring – Navigational guidance where air traffic controller issues a compass heading to a pilot. Shoreline Departure – Departure via Runways 28 that utilizes a right turn toward San Francisco Bay as soon as feasible. The Shoreline Departure is considered a noise Reliever Airport – An airport for general aviation and other aircraft that would otherwise abatement departure procedure. use a larger and busier air carrier airport. SID - Standard Instrument Departure - An aeronautical chart designed to expedite RMS – Remote Monitoring Site - A microphone placed in a community and recorded at clearance delivery and to facilitate transition between takeoff and enroute operations. San Francisco International Airport’s Noise Monitoring Center. A network of 29 RMS’s S V SENEL – Single Event Noise Exposure Level - The noise exposure level of a single Vector – A heading issued to a pilot to provide navigational guidance by radar. Vectors are aircraft event measured over the time between the initial and final points when the noise assigned verbally by FAA air traffic controllers. level exceeds a predetermined threshold. It is important to distinguish single event noise VFR – Visual Flight Rules are rules governing procedures for conducting flight under levels from cumulative noise levels such as CNEL. Single event noise level numbers are visual meteorological conditions, or weather conditions with a ceiling of 1,000 feet above generally higher than CNEL numbers, because CNEL represents an average noise level ground level and visibility of three miles or greater. It is the pilot’s responsibility to maintain over a period of time, usually a year. visual separation, not the air traffic controller’s, under VFR. Single Event – Noise generated by a single aircraft overflight. Visual Approach – Wherein an aircraft on an IFR flight plan, operating in VFR conditions SOIA – Simultaneous Offset Instrument Approach Is an approach system permitting under the control of an air traffic facility and having an air traffic control authorization, may simultaneous Instrument Landing System approaches to airports having staggered but proceed to destination airport under VFR. parallel runways. SOIA combines Offset ILS and regular ILS definitions. VASI – Visual Approach Slope Indicator - An airport lighting facility in the terminal area STAR – Standard Terminal Arrival Route is a published IFR arrival procedure describing navigation system used primarily under VFR conditions. It provides vertical visual guidance specific criteria for descent, routing, and communications for a specific runway at an to aircraft during approach and landing, by radiating a pattern of high intensity red and airport. white focused light beams, which indicate to the pilot that he/she is above, on, or below the glide path. T VMC – Visual Meteorological Conditions - weather conditions equal to or greater than Taxiway – A paved strip that connects runways and terminals providing the ability to move those specified for aircraft operations under Visual Flight Rules (VFR). aircraft so they will not interfere with takeoffs or landings. Terminal Airspace - The air VOR - Very High Frequency Omni-directional Range – A ground based electronic space that is controlled by a TRACON. navigation aid transmitting navigation signals for 360 degrees oriented from magnetic Terminal Area – A general term used to describe airspace in which approach control north. VOR is the historic basis for navigation in the national airspace system. service or airport traffic control service is provided. Threshold – Specified boundary. W TRACON -Terminal Radar Approach Control – is an FAA air traffic control service to X aircraft arriving and departing or transiting airspace controlled by the facility. TRACONs control IFR and participating VFR flights. TRACONs control the airspace from Center down Y to the ATCT. Z U Questions?
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