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 showing Oakland Airport with runways and nearby cities. Blue arrows indicate preferred VFR departure paths over water. Red-shaded areas mark residential and hotel zones (Alameda, Bay Farm Island, San Leandro, and Marina District) to avoid. Green dashed lines show the I-880 Nimitz Freeway. Runways are labeled (e.g., 10L, 10R, 28L), and the San Leandro Bay is shown between flight paths.

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
Aerial view of Oakland Airport and surrounding area. Large blue arrows show nighttime VFR departure routes that loop over water to avoid red-shaded residential areas: Alameda, Bay Farm Island, San Leandro, and the Marina District. The I-880 Nimitz Freeway is marked with a dashed green line. The preferred routes help reduce aircraft noise impact between 10 PM and 6 AM.

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
Aerial map of Oakland Airport showing a beige rectangular loop over Runway 28R, representing the preferred pattern for touch-and-go operations. Red-shaded areas mark residential and hotel zones to avoid, including Alameda, Bay Farm Island, San Leandro, and the Marina District. The green dashed line shows the I-880 Nimitz Freeway. The pattern avoids flying over populated areas to reduce noise disturbance.

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.

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.

Evolution of Aircraft Noise Stages in U.S.

Chart showing EASA-certified aircraft noise levels relative to Chapter 3 limits from 1960 to 2035, categorized into Stages 2 through 5. The y-axis represents cumulative noise margin in EPNdB, and the x-axis shows certification years. Symbols represent different aircraft types: triangles for Regional Jets, squares for Short/Medium Range 2-engine, diamonds for Long Range 2-engine, and circles for Long Range 4-engine aircraft.
Sound exposure level contours for nine aircraft types, ranging from Stage 2 to Stage 5. The contours show noise levels from 80 dBA to over 95 dBA, with darker shades indicating higher noise. Older aircraft like the 727Q15 (Stage 2) and 727EM2 (Stage 3) have larger and louder noise footprints, while newer aircraft like the 737MAX8 and A320-271N (Stage 5) have smaller, quieter contours. A distance scale in nautical miles is shown along the bottom axis.

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 showing A, B, and C frequency weighting curves. The red A-weighting curve heavily reduces low frequencies, the green B-weighting curve moderately reduces them, and the blue C-weighting curve remains nearly flat across the frequency range. The graph shows frequency on the x-axis (20 Hz to 40,000 Hz) and level on the y-axis from -50 dB to +10 dB.

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 show aircraft noise levels over time using different metrics. First graph: A sound level curve peaks at 102.5 dB, labeled as Lmax. Second graph: The same curve with a shaded area under it showing total sound energy (SEL = 108.0 dB) and event duration. Third graph: The same event with a box representing average energy over 15 seconds (Leq = 96.5 dBA). All graphs plot sound level (dB) on the y-axis and time (seconds) on the x-axis.

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
A bar graph showing hourly noise levels from 7 AM to 7 AM the next day. The graph is divided into day, evening, and night periods. Daytime noise has no adjustment, evening noise (7–10 PM) is increased by 5 dB (3x weighting), and nighttime noise (10 PM–7 AM) is increased by 10 dB (10x weighting). The CNEL is marked at 67 dB with arrows showing the added weighting for evening and night periods.

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

An aircraft is shown on a runway with white arrows labeled “Noise” curving upward into the sky. The left side of the image is labeled "Warm" near the ground and "Cool" in the upper sky, indicating a temperature gradient. The arrows illustrate how sound bends upward in these conditions, reducing ground-level noise impact.
An aircraft is shown on a runway at night, with stars in the sky. The image is labeled “Warm” at the top and “Cool” near the ground. White arrows labeled “Noise” curve downward toward the ground, illustrating how sound bends toward the surface during a temperature inversion, increasing ground-level noise exposure.

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)
A front-facing aircraft is shown on the ground with blue arrows indicating wind blowing from left to right. Red arrows labeled “Noise” curve upward and away on the upwind side (left) and downward toward the ground on the downwind side (right), illustrating how wind carries aircraft noise farther downwind.

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

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.