Order 1434280: Read Instructions

Aircraft Noise Mitigation

Ryan Wallace, Ed.D.

Overview

• FAA Approved Methods for Noise Measurement

• Noise Contour Mapping

• Airport Project Noise Analysis Requirements

• Primary & Alternative Noise Screening Tools

• Government Strategies to Prevent New Non-

Compatible Developments

• Airport Operator Noise Control Options

• Matrix of Noise Control Actions

• Land Use Compatibility Chart

FAA Approved Methods for

Measuring Noise • Yearly Day-Night Average

Sound Level (DNL) – Average aircraft sound

levels at a location over a 24-hour period

– Add 10 dB adjustment to noise occurring between 10 PM-7AM due to increased sensitivity

• Community Noise Equivalent Level (CNEL) – Alternative to DNL scale

approved for FAA projects in California

– Adds additional 4.77 dB to noise events occurring between 7 PM-10 PM

Noise Contour Map (KLAL)

Noise Contour Map (KOAK)

When is a Noise Analysis

Required? • No noise analysis is needed for the

following projects:

• Project involving – Design group I & II aircraft (wingspan

<79 ft)

– Approach categories A-D (landing speed < 166 kts)

– Operating at airports where NEPA forecasts do not exceed

• 90,000 annual propeller operations or

• 700 annual jet operations

– Results in a • DNL 65 db counter <0.5 mi2 extending

no more than 10,000 ft

• DNL 60 dB contour < 1.1 mi2 extending no more than 12,000 ft

• Project involving – Helicopters including Sikorsky S-70 or

max gross weight of 20,224 lbs or less

– Heliports or airports where NEPA forecasts do not exceed an average of 10 daily helicopter operations

– Average operations with hover times do not exceed 2 minutes

– Results in a • DNL 65 dB contour of < 0.1 mi2

extending no more than 1,000 ft

Primary FAA Noise Screening Tools

• Area Equivalent Method (AEM) – Mathematical procedure for

estimating noise contour area

– Suitable for evaluating airport projects involving:

• General overall increase in operations, or larger/noisier aircraft

• No changes in ground tracks or flight profiles

– If AEM indicates • <17% increase (about

DNL 1 dB) in DNL 65 dB contour area, no further noise analysis required

• >17% in DNL 65 dB contour area, then Aviation Environmental Design Tool must be used

Primary FAA Noise Screening Tools

• Aviation Environmental

Design Tool (AEDT)

– Computer modeling tool to

assess aircraft

performance, with

emphasis on

• Fuel consumption

• Emissions

• Noise

• Air Quality

– Identifies noise level

changes at various

intervals

• DNL 65 dB+: ± 1.5 dB

• DNL 60-64 dB: ± 3 dB

• DNL 45-59 dB: ± 5 dB

Alternative Noise Screening Tools

• NOISIEMAP (DOD) – Models noise exposure in

vicinity of military air bases due to aircraft flight & engine run-up activities

– Used when study consists predominantly of military operations

• Military Operating Area & Range Noise Model (MR_NMAP) – Models noise levels from

subsonic aircraft

– Military Training Routes (MTR), Military Operating Areas (MOA), & Special Use Airspace

• PCBOOM – Models location & magnitude

of sonic boom on ground due to supersonic flight & space operations

Noise Control Challenges

• Managing airport noise can be challenging because – Airports are

responsible for noise mitigation, even though aircraft operators are the producers of noise

– State & local governments control zoning restrictions, which in turn dictates land use around airports

Government Strategies to Prevent New

Non-Compatible Developments • Land use and development controls

are exercised by local governments, not airport operator

• Primary methods – Zoning: designating permitted uses

for parcels of land • Land usage constraints

• Usually administrated by a legislative body

• Zoning body not bound by previous zoning restrictions

• Not retroactive

• Not all counties have zoning authority (particularly in rural areas)

– Easement: Right for using property of another without possessing it

• Generally obtained through purchase, condemnation, or dedication

– Transfer of Development Rights (TDR)

• Landowners can sell development rights from non-noise compatible land ni exchange for bonus development rights on compatible land

• Voluntary, incentive-based program

Acquisition of Impacted Land • In some areas, there are few options

for noise control other than direct acquisition by the airport or local government entity

• Noise impacted land can be used for public use

– Equipment maintenance, storage, water/sewer works, floodways, reservoirs, etc

• Airport or government agency acquires land and resells with

– Easement:

• Right for using property of another without possessing it

• Represents a real property interest

– Covenant:

• Promise made by a party to engage or refrain from a conduct

• Covenants function like contracts and are not binding on future owners

Airport Operator Options to Control

Noise • Denial of use to aircraft not

meeting Federal Noise Standards (14 CFR Parts 36 & 91)

• Capacity limits, based on noise

– Can have a detrimental economic effects

– Restrictions based on cumulative impact

• Limits aircraft types or numbers, to not exceed a designated noise threshold

– Restrictions based on certificated noise levels

• Limitations based on aircraft type noise certification level

– Restrictions based on single event noise levels

• Similar strategy to certificated restrictions, except applies to individual aircraft

Airport Operator Options to Control

Noise • Noise Abatement Takeoff

or Approach procedures

– Goal: achieve greatest

noise relief within

parameters of safety,

economics, & in

coordination with airport’s

compatible land use

strategies

– Runway selection

– Takeoff & landing profiles &

power settings

– Approach or departure

paths

Airport Operator Options to Control

Noise • Landing fees based on noise

– Bases all or a portion of the landing fee upon the noisiness of individual aircraft

– Should be based on single-event noise ratings for aircraft (AC-36-3B)

– Alternatively, provide incentives or discounts to landing fees for quiet aircraft

• Noise Barriers – Use of sound barriers or shielding such as

berms, or “hush houses,” or strategic building plans to block noise

– Generally effective against ground-based noise such as aircraft run-up, maintenance, cargo handling, etc

• Curfews – Restrictions on some or all flights during

certain periods of day

– Restrictions generally based on noise threshold or aircraft certificated noise level

– Usually employed to restrict operations during noise sensitive periods (10 PM-7 AM)

– Costly method of noise control, since it curtails economic development; generally used as a last resort

Soundproofing • Increasing the exterior to

interior sound transmission losses of a building

– Identifying structural elements providing transmission pathways

– Applying modifications to improve noise attenuation

• Common Soundproofing Techniques (existing structure)

– Sealing existing leaks (5 dB)

– Retrofit of existing buildings

• Window replacement or adding second layer of glass

• Upgrading doors & seals

• Acoustic baffling of vents

• Adding insulation to walls or attic spaces

• Creating two-panel walls

• Eliminating windows

Soundproofing • Common Soundproofing

Techniques (new structure)

– Brick or concrete masonry walls

– Staggered studs

– Insulation & fiberboard under interior & exterior finish materials

– Attic space insulation

– Baffling vents

– No single-joint roof construction (interior & exterior materials attached to same rafters)

– Avoid exposed rafter ceilings

– Installation of air conditioning

– Mortar free of pinholes

– Joints well-sealed

Matrix of Noise Control Actions

Land Use Compatibility Chart

Summary

• FAA Approved Methods for Noise Measurement

• Noise Contour Mapping

• Airport Project Noise Analysis Requirements

• Primary & Alternative Noise Screening Tools

• Government Strategies to Prevent New Non-

Compatible Developments

• Airport Operator Noise Control Options

• Matrix of Noise Control Actions

• Land Use Compatibility Chart