Table of Contents

Background

OAK Noise Program History Timeline

For more than 40 years, the Port of Oakland has endeavored to develop programs that minimize noise impacts on surrounding communities at Oakland San Francisco Bay Airport (OAK).

OAK Noise Abatement

OAK Voluntary Noise Abatement Program

  • Designed to minimize aircraft noise in the surrounding communities

  • Developed through meetings with:

    • Local communities
    • FAA representative
    • Aircraft operators, e.g., airlines and pilots
  • Pilot education is the cornerstone
  • Monitoring system separates fact from fiction
  • The Port operates the airport with the full integration of noise abatement

OAK Flight Track/Noise Monitoring

  • The airport operates an Aircraft Noise and Operations Monitoring System (ANOMS™) to

    • Monitor compliance with voluntary noise abatement procedures
    • Address community and stakeholder concerns
    • Used to respond to community and stakeholder request for aircraft noise information

  • The airport maintains 14 permanent noise monitors located throughout local communities and an additional one located within the airport Ground Runup Enclosure (GRE)

Aerial map of Oakland Airport with preferred VFR departure routes over water and residential areas to avoid.

Oakland Airport VFR Departure Guidance and Residential Noise Avoidance Zones. This aerial map of the Oakland International Airport area highlights preferred VFR (Visual Flight Rules) departure routes in solid blue arrows, directing aircraft over the San Leandro Bay and away from residential communities. Areas shaded in red—including Alameda, Bay Farm Island, San Leandro, and the Marina District—are labeled as sensitive residential and hotel zones to avoid. The I-880 Nimitz Freeway is shown as a dashed green line for geographic reference. This guidance helps minimize aircraft noise impact on surrounding communities.

North Field Preferred VFR Departure Noise
Abatement Runway 28L/R & 33

  • Runway 28L/R

    • VFR departures should include a right crosswind or additional downwind segment avoiding Bay Farm Island and the main island of Alameda (propeller/turboprop)
  • Runway 33

    • Make right northerly turn over San Leandro Bay until reaching I-880
    • No straight-out or left crosswind/downwind departures
Map of nighttime VFR departure routes from Oakland Airport designed to reduce noise.

Oakland Airport Preferred Nighttime VFR Departure Routes and Noise-Sensitive Areas. This aerial map displays preferred nighttime VFR (Visual Flight Rules) departure routes from Oakland International Airport, recommended between 10:00 PM and 6:00 AM local time. The dark blue arrows indicate flight paths designed to minimize noise impact on nearby communities by routing aircraft over water. Residential and hotel areas to avoid are shaded in red, including Alameda, Bay Farm Island, San Leandro, and the Marina District. The I-880 Nimitz Freeway is shown in dashed green for reference.

North Field Night Departure Noise Abatement Runway 28L/R &10L/R

  • Runway 10R

    • VFR and IFR departures use 180-degree departure heading for E/SE departures or for N/NE departures
    • No left turn departures
  • Runway 28R

    • SALAD ONE departure (propeller/turboprop); do not use the OAK 313 or 310 heading departure
    • Right crosswind over San Leandro Bay until reaching I-880 (propeller/turboprop)
    • No straight-out departures
Map of Oakland Airport showing the preferred touch-and-go traffic pattern to reduce noise.

Preferred Touch-and-Go Pattern at Oakland Airport and Noise-Sensitive Areas. This aerial map highlights the preferred runway and flight pattern for touch-and-go operations at Oakland International Airport. The beige oval outlines a rectangular loop over Runway 28R, designed to keep aircraft operations away from nearby residential and hotel areas, which are shaded in red. These sensitive zones include Alameda, Bay Farm Island, San Leandro, and the Marina District. The I-880 Nimitz Freeway is shown in dashed green for orientation. This guidance helps minimize noise impacts during repetitive training flights.

North Field Touch & Go Noise Abatement
Runway10R/28L

  • Standard traffic pattern altitude at approximately 600’ above ground level (AGL).

Ground Run-Up Enclosure (GRE)

  • Three-sided structure on the OAK airfield designed to reduce noise from aircraft engine testing

    • Opened in 2002 – First in California
    • Sized to fit up to a widebody commercial jet aircraft, e.g., Boeing 747
    • Provides up to 17 dB noise reduction from engine run-ups
Ground Run-Up Enclosure (GRE)

Noise Regulations

Federal Noise Regulations

Table: Key U.S. Statutes Related to Aircraft Noise and Relevant FAA Regulations
Statute Aircraft Noise Related Purpose Most Relevant FAA Regulation(s)
Aircraft Noise and Sonic Boom Act of 1968 Authorizes FAA to prescribe standards for measurement of aircraft noise and establish regulations to abate noise 14 CFR parts 36 and 91
National Environmental Policy Act of 1969 (NEPA) Directs all federal executive agencies to assess all environmental effects of proposed federal agency actions FAA Orders 1050.1F, 5050.4B
The Noise Control Act of 1972 (Noise Act) Amends 1968 act to add consideration of public health and welfare and to add EPA to the rulemaking process for aircraft noise and sonic boom standards None directly; EPA responsibility
Aviation Safety and Noise Abatement Act of 1979 (ASNA) Directs FAA to establish single system to measure noise and determine exposure of people to noise, and identify land uses normally compatible with various noise levels 14 CFR part 150
Airport and Airway Improvement Act of 1982 Authorizes FAA funding for noise mitigation/compatibility planning and projects and establishes noise compatibility requirements for FAA-funded airport development FAA Airport Improvement Program
Airport Noise and Capacity Act of 1990 (ANCA) Mandates phase out of Stage 2 jet aircraft over 75,000 pounds, and established requirements regarding airport noise and access restrictions for Stage 2 and 3 aircraft 14 CFR part 161
Section 506 of the FAA Modernization and Reform Act of 2012 Prohibition after 12/31/2015 of operation of civil subsonic jet airplanes with maximum weights of 75,000 pounds or less that do not meet stage 3 noise standards 14 CFR part 91
FAA Reauthorization, 2024 Reauthorizes FAA through September 30, 2028 None yet

Aircraft Noise Standards (14 CFR Part 36)

  • Noise standards vary by design criteria and for most aircraft are in terms of “stages”
  • Aircraft must meet Part 36 standards to obtain new or revised “type” or “airworthiness” certificates to operate in the U.S.
  • The standards address noise limitations depending on aircraft type and weight

  • Certification for most – but not all – aircraft is based on three measurements: Landing, Sideline, and Takeoff

Aircraft approach diagram showing glide path, sideline references, and noise measurement points.

Diagram of Aircraft Approach Noise Measurement Reference Points. An aircraft approaches a runway along a 3-degree glide slope toward the Approach Reference Point, which is located 2,000 meters from the runway threshold and 120 meters above the ground. Sideline (lateral) reference points are marked 450 meters to the left and right of the runway centerline. This layout is used for consistent measurement of aircraft noise during approach operations.

Measurement locations can vary with aircraft stage, number of engines, and lift mechanism. Some types are certificated based on level flyover.

Diagram showing takeoff noise measurement reference points: 6,500 meters from start of takeoff roll and 450 meters to each side for lateral references.

Diagram of Aircraft Takeoff Noise Measurement Reference Points. An aircraft is shown during takeoff, with the Takeoff/Flyover Reference Point located 6,500 meters from the start of the takeoff roll. Two Sideline (Lateral) Reference Points are positioned 450 meters to the left and right of the runway centerline. These points are used to measure aircraft noise levels during the takeoff phase in accordance with standard aviation noise monitoring procedures.

Evolution of Aircraft Noise Stages in U.S.

Chart showing reductions in certified aircraft noise levels relative to Chapter 3 limits over time.

EASA Certified Aircraft Noise Levels Relative to Chapter 3 Limits by Compliance Stage (1960–2035). This chart displays the cumulative noise margin (in EPNdB) of various aircraft types certified under EASA, grouped by compliance with Stages 2 through 5. Stage 2 compliant aircraft were phased out by 1977, Stage 3 by 2006, and Stage 4 by 2017. Stage 5 compliance is shown for aircraft certified from 2017 onward. The data includes Regional Jets, Short/Medium Range 2-engine (SMR2), Long Range 2-engine (LR2), and Long Range 4-engine (LR4) aircraft.

Noise contour comparison showing newer aircraft produce smaller, quieter noise footprints than older models.

Comparison of Aircraft Sound Exposure Levels by AEDT Type and Certification Stage. This graphic shows sound exposure level (SEL) contours for nine aircraft types across Stages 2 to 5 certification categories, using AEDT modeling. The contours represent noise levels from 80 to over 95 dBA in decreasing shades of blue, with older Stage 2 and Stage 3 aircraft (e.g., 727Q15, 727EM2, MD83) producing broader and louder noise footprints compared to newer Stage 4 and Stage 5 aircraft (e.g., 737MAX8, A320-271N). The x-axis provides a distance scale in nautical miles (1 NM = 6,076 feet).

Noise Thresholds for Aviation Environmental Analyses

Significant Impact

  • 1.5 dB increase within 65 DNL

Less than significant impact
  • 3 dB increase between 60 and 65 DNL
  • 5 dB increase between 45 and 60 DNL triggers additional analyses for air traffic actions
Historical Background
  • Federal Interagency Committee on Noise (“FICON”), 1992

    • 1.5 dB increase in DNL within 65 dB DNL
    • 3 dB increase in DNL between 60 and 65 dB DNL
  • Expanded East Coast Plan (“EECP”) EIS, 1992-3

  • FAA Order 7400.2M (Policies and Procedures for Air Traffic Environmental Actions)

  • FAA Order 5050.4B NEPA Implementing Instructions for Airport Actions
  • Order 1050.1F “Desk Reference” provides detailed guidance

Change in Noise Level from No Action Alternative to Proposed Action

Table: Proposed DNL and Associated Increases/Decreases with Color Indicators
“Proposed” DNL Increase (with color indicator) Decrease (with color indicator)
< 45 dB No change — no color applied No change — no color applied
45 to < 50 dB Increase ≥ +5 dB (yellow) Decrease ≤ -5 dB (magenta)
50 to < 55 dB Increase ≥ +5 dB (yellow) Decrease ≤ -5 dB (magenta)
55 to < 60 dB Increase ≥ +5 dB (yellow) Decrease ≤ -5 dB (magenta)
60 to < 65 dB Increase ≥ 3 dB (orange) Decrease ≤ -3 dB (blue)
≥ 65 dB Increase ≥ 1.5 dB (red) Decrease ≤ -1.5 dB (green)

Airport Noise Compatibility Planning (14 CFR Part 150)

The Aviation Safety and Noise Abatement Act of 1979 (“ASNA”) required FAA to:
  • Establish a single, uniform, repeatable system for considering aviation noise around airport communities.
  • Establish a single system for determining noise exposure from aircraft, which takes into account noise intensity, duration of exposure, frequency of operations, and time of occurrence.
  • Identify land uses which are normally compatible with various exposures of individuals to noise

14 CFR Part 150 prescribes
standards and systems for:

  • Measuring noise
  • Estimating cumulative noise exposure using computer modeling
  • Describing noise exposure
  • Coordinating with local land use agencies
  • Documenting the analytical process
  • Submitting the documentation to FAA
  • FAA and public review processes
  • FAA approval or disapproval process

Airport Noise and Capacity Act of 1990, ANCA

Table: FAA Actions on Act Requirements
Act Requirement FAA Action
Required FAA to establish phase-out of Stage 2 aircraft over 75,000 pounds FAA promulgated Part 91 amendment (1991)
Required FAA to establish regulations regarding analysis, notice, and approval of airport noise and access restrictions FAA implemented through FAR Part 161 (1991)
Required FAA to develop “national aviation noise policy” by July 1, 1991 FAA published draft “Aviation Noise Abatement Policy 2000” on July 14, 2000 to replace the 1976 Federal Noise Abatement Policy

Notice and Approval of Airport Noise and Access Restrictions 14 CFR Part 161

Establishes the federal program for reviewing noise and access restrictions on the use of Stage 2 and 3 aircraft (and perhaps beyond)
  • Requires extensive benefit cost analyses
  • Requires extensive notice process
  • Requires different level of analysis for Stage 2 and 3
  • Requires separate analysis of effects on aircraft less than 75,000 pounds
  • Encourages voluntary agreements
  • Measure of last resort for land use compatibility

Noise Standards – California

  • The State of California enacted aviation noise standards for the Department of Transportation (Caltrans) Aeronautics Department

    • Title 21 (Register 90, No. 10—3-10-90) Subchapter 6, Noise Standards

  • California Noise Standards Include:

    • Definition of “noise problem” airport for the County in which the airport resides to make such a designation
    • Implementation by counties, airports and Caltrans
    • Variances to operate if incompatible land use exists
    • Noise monitoring system requirements and specifications

Title 21 Reporting Requirements

  • County (not the airport proprietor) submits quarterly to Caltrans for each noise problem airport within 75 days of the end of each quarter

    • A map showing the noise impact boundary for the preceding “four calendar quarters”“as validated by measurement” and the location of the measurement locations
    • The annual noise impact area and number of dwelling units and people residing within
    • Daily noise measurement for the calendar quarter using the Community Noise Equivalent Level (CNEL) metric
    • Number of total aircraft operations for the calendar quarter
    • Number of aircraft operations for the highest noise level aircraft in the calendar quarter
    • Form DOA 671, dated 10/89

Measurement of CNEL

To calculate daily CNEL from measurement of aircraft operations, Title 21 requires:

  • Threshold noise level of 55 dB to capture single noise events

    • Waiver is required for Caltrans to allow the level greater than 55 dB

  • Single Event Noise Exposure Level (SENEL) be used as the total noise energy of aircraft operation as it is the noise exposure, in decibels, of a single event measured over the time interval the noise level exceeds a predetermined threshold noise level

  • Hourly Noise Levels (HNL) be calculated from noise events associated with aircraft operations, retained for at least three years and made available upon request

About Noise

Noise Definition

  • Noise is simply defined as “unwanted sound”

  • Sound results from small and rapid changes in air pressure our ears detect

  • We characterize and judge sounds by:

    • Magnitude (loudness) in decibels (dB)
    • Frequency (pitch) in hertz

  • The EPA has adopted the A-weighted sound level for environmental analyses

    • All sound levels presented in aircraft noise studies are A-weighted unless otherwise specified
Graph comparing A, B, and C frequency-weighting curves used in sound measurement.

A-, B-, and C-Weighting Frequency Response Curves for Sound Level Measurement. This graph compares the frequency response curves of A, B, and C weighting filters used in sound level meters. The x-axis represents frequency in Hertz (Hz) from 20 Hz to 40 kHz, and the y-axis shows level in decibels (dB). Curve A (red) emphasizes mid-frequency sensitivity and significantly attenuates low-frequency sounds. Curve B (green) offers moderate low-frequency attenuation, and Curve C (blue) provides a relatively flat response, preserving more low- and high-frequency content. These filters are used to simulate human hearing sensitivity under different sound pressure levels.

Studies have resulted in loudness curves:

  • A-weighted noise levels correlate to loudness of sounds in our everyday environment (relatively low energy)
  • B-weighted noise levels correlate to medium energy sounds
  • C-weighted noise levels correlate to high energy sounds

Noise Terminology

  • Maximum A-weighted Sound Level (Lmax)
  • Sound Exposure Level (SEL) and Single-Event Noise Exposure Level (SENEL – requires a threshold)
  • Equivalent Sound Level (Leq)
Three graphs comparing aircraft noise measurements using Lmax, SEL, and Leq metrics.

Illustration of Common Aircraft Noise Metrics: Lmax, SEL, and Leq. The three side-by-side graphs depict how different aircraft noise metrics are calculated. The first graph shows Lmax (maximum sound level), which is the peak of the sound curve, measured at 102.5 dB. The second graph adds Sound Exposure Level (SEL), which integrates total sound energy over the event duration (shaded area), shown as 108.0 dB. The third graph illustrates Equivalent Continuous Sound Level (Leq), representing the average energy over a 15-second period, shown as 96.5 dBA.

Community Noise Equivalent Level (CNEL)

  • Describes the noise dose for a 24-hour period
  • Accounts for event “noisiness” (SEL)
  • Accounts for number of noise events

  • Provides an additional weighting for evening and nighttime operations

    • Daytime is defined as 7:00 am to 7:00 pm
    • Evening is defined as 7:00 pm to 10:00pm
    • Nighttime is defined as 10:00pm to 7:00am
Bar graph illustrating how evening and nighttime noise is weighted more heavily in the CNEL metric.

Community Noise Equivalent Level (CNEL) with Time-of-Day Weighting Adjustments. This bar graph illustrates how noise levels throughout a 24-hour period are adjusted using time-of-day weighting to calculate the CNEL, shown here as 67 dB. The graph divides the day into three periods: Day (7 AM – 7 PM): No additional weighting. Evening (7 PM – 10 PM): Weighted by a factor of 3, equivalent to +5 dB. Night (10 PM – 7 AM): Weighted by a factor of 10, equivalent to +10 dB. Dark gray and blue bars highlight the increased weighting during evening and night, which amplify their contribution to the CNEL metric, emphasizing the greater impact of noise during sensitive hours.

Noise Sources & Propagation

Aircraft Noise Sources

Airplane taking off in sky

Departure Noise

Airplane landing

Arrival Noise

taxing airplane

Ground Noise

Sound Propagation

Illustration of an airplane flying toward the viewer, with red concentric circles surrounding it to represent radiating sound waves. The background includes a blue sky with scattered white clouds.

Spherical Spreading:

  • Sound level decreases by 6 dB per doubling of distance
  • Additional losses due to atmospheric absorption
Diagram showing an aircraft on a runway with two red arrows pointing toward a house. One arrow is labeled "Direct" and travels in a straight line to the house. The second arrow is labeled "Reflected" and bounces off the ground before reaching the house, representing how sound reflects off surfaces.

Ground Effect:

  • Sound levels are lower when reflected off soft ground vs. hard ground

Illustration showing how sound bends upward in warm-to-cool air, reducing aircraft noise at the ground.

Illustration of Upward Refraction of Aircraft Noise in Normal Atmospheric Conditions. This diagram shows how aircraft noise propagates upward when cool air overlays warm air, a common condition during the daytime. The temperature gradient causes sound waves to refract upward, reducing the amount of noise that reaches the ground. Curved white arrows represent the redirected noise paths moving away from the surface.

Illustration showing how a nighttime temperature inversion bends aircraft noise toward the ground.

Illustration of Downward Refraction of Aircraft Noise During Temperature Inversion. This diagram shows how aircraft noise propagates during temperature inversion conditions, typically at night, when warm air overlays cooler air near the ground. The inversion causes sound waves to refract downward, concentrating more noise toward the surface and increasing its impact on surrounding communities. White curved arrows represent the downward bending of sound paths.

Refraction due to Temperature:

  • Gradients in temperature cause the bending of sound paths
  • Sound bends upward during a temperature lapse (cool air over warm)
  • Sound bends downward during a temperature inversion (warm air over cool)
Diagram explaining how wind direction affects the spread of aircraft noise.

Illustration of Wind Effects on Aircraft Noise Propagation. This diagram shows how wind direction influences the spread of aircraft noise. With wind blowing from left to right (upwind to downwind), noise is deflected upward and away in the upwind direction, while in the downwind direction, sound waves bend toward the ground. This results in greater noise exposure for downwind areas, as shown by the red arrows representing noise propagation paths.

Refraction due to Wind:

  • Gradients in wind speed cause the bending of sound paths
  • Sound bends upward causing sound shadows in the upwind direction
  • Sound bends downward increasing sound levels in the downwind direction
  • Differences between upwind and downwind directions can be 20 dB

Measurements vs. Modeling

Photos of outdoor aircraft noise monitoring equipment installed in Alameda, California.

Examples of Outdoor Noise Monitoring Equipment Installations in Alameda, CA. These photos show three different noise monitor enclosures mounted on poles and a building wall in Alameda, California. The left and center images display pole-mounted metal boxes, one closed and one open to reveal internal electronic components. The right image shows a wall-mounted unit on the side of a commercial or industrial building. Each image includes GPS coordinates, time, and date stamps, confirming precise monitor placement for community aircraft noise tracking.

Measurements

  • Provide historical noise levels at discrete points
  • Difficult to attribute noise entirely to aircraft operations
  • Reports noise levels from individual aircraft operations
Grid of sound level data points marked with “+” symbols. Each point shows a numerical sound level in decibels (dB), ranging from about 51.8 dB to 92.3 dB. Higher values are concentrated in the bottom right area, near a diagonal gray line that may indicate a runway or flight path.

Modeling

  • Provides past or future noise levels throughout the study area
  • Produces results from only aircraft operations
  • Generates noise levels from average daily aircraft operations
  • Calculates consistent, comparable outputs (if consistent inputs)
Aerial Map of Oakland Airport (OAK) with Noise Monitoring Locations and Contour Lines.