2021 REDAC Fall Meeting

Research on Operational Procedures

REDAC NAS Operations Subcommittee 

Chris Dorbian

FAA Office of Environment & Energy

Aircraft Technology & Operations Division (AEE-200)

September 1, 2021

Presented to:

By:

Date:
Environmental & Energy (E&E) Strategy

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E&E Mission: To understand, manage, and reduce the environmental impacts of global aviation through research, 

technological innovation, policy, and outreach to benefit the public

E&E Vision: Remove environmental constraints on aviation growth by achieving quiet, clean, and efficient air transportation

E&E R&D Portfolio Activities & Programs

www.ascent.aero/

www.faa.gov/go/cleen/

www.caafi.org/
Over a ninety percent decrease in community noise exposure while increasing enplanements by nearly 

a factor of five; however, the noise experience is different than it was in decades past

Data source: FAA enplanement data and noise analyses using AEDT 3

Historical Trends in Noise Exposure and Enplanements
• Aircraft noise from 1970s is different 

than aircraft noise today. 

• A single aircraft from the 1970s 

produced the same acoustic energy 

as 10 to 30 aircraft operations today.

• A few, but relatively loud, operations 

in the 1970s would result in DNL 65 

dB. Many, relatively quiet operations 

today would also result in DNL 65 

dB. However, the noise experience 

is very different.

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1,000 Events/Day SEL 84.4 dBA = DNL 65

Aircraft Noise in the Last Decade (1 of 2)
Aircraft Noise in the Last Decade (2 of 2)

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• Recent efforts to modernize the national air 

transportation system have required changes in aircraft 

operational patterns

• While modernization is needed to increase public safety 

and system efficiency, the changes in operational 

patterns have also led to increased concern about 

aircraft noise

• While air space redesigns have been taking place, 

operations by air carriers have also increased

• Airport communities that are outside the DNL 65 dB 

contour are expressing concerns about aircraft noise

0

200000

400000

2010 2012 2014 2016 2018

Annual Air Carrier Operations

65dB

Each marker represents a unique complaint 

address

Arrivals in Green

Departures in Red

Data Sources: 

Brenner, M., Hansman, R. J., “Comparison of Methods for Evaluating Impacts of Aviation Noise on 

Communities,” 2017

FAA Data on Annual Air Carrier Operations for Boston Logan International Airport
Effects of Aircraft Noise on Individuals and Communities

• Speech Interference and Children’s Learning

• Neighborhood Environmental Survey

• Health and Human Impacts Research 

– Cardiovascular Health

– Sleep Disturbance

• Economic Impacts

Noise Modeling, Noise Metrics and Environmental Data Visualization

• Aviation Environmental Design Tool

• Noise Screening

• Environmental Data Visualization

• Supplemental Noise Metrics

Reduction, Abatement and Mitigation of Aviation Noise

• Aircraft Source Noise Reduction

• Noise Abatement

• Noise Mitigation Research

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FAA Noise Research Program – Overview
FAA Efforts Relating to Low Noise Aircraft Operations

1. Investigation of operational opportunities for noise reduction:

– Airlines largely determine what aircraft fly and when

– There might be opportunities to change where aircraft fly (through precision navigation) and how aircraft are flown

– Must consider the entirety of the airspace and ensure the continued safety of operations

– Concepts being evaluated:

 Route changes

 Thrust / speed / configuration management

 Vertical profile modifications

 Systematic dispersion

2. Validation of noise abatement procedures

– Operationally validate (through flight sim/testing, noise measurement, etc.) noise management concepts

3. Advancement of tools, processes, and policies

– Execution of knowledge, guidance, & tools/options to manage noise

– Examination of metrics to facilitate assessment/communication of noise impacts

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FAA

-Massport MOU

• Memorandum of Understanding signed in 

September 2016 established framework for 

cooperation between Massport & FAA to explore 

operational changes to mitigate noise impacts

• MIT developed noise evaluation framework 

(through ASCENT-23) and is applying it (through 

Massport funding) to BOS to build and assess 

procedures

• FAA and industry are providing feedback on the 

operational feasibility of these ideas

• MIT ideas separated into two blocks: – Block 1: Clear noise benefit, no equity issues, 

limited operational/technical barriers

– Block 2: More complex due to potential 

operational/technical barriers or equity issues 

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Example MOU Procedures

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Block 1: 15R Departure Block 2: 33L Departure
Communicating Impacts

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N60 Thresholds:

60dB LA,max Day, 50dB LA,max Night

N60 50x

Baseline 2017 335,823

Divergent 

Headings Rev 2 352,775

Baseline -

Dispersion -16,952

Population Exposure

Analysis updated Oct. 17 2019 to remove Turboprops and refine 

lateral tracks

Modeling/Discretization effects near airport removed

Analysis based on peak day operations; only 

includes 33L departures
A Closer Look...

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EXAMPLE ONLY
Federal Aviation

Administration

Changing Start of Deceleration on Arrival (Delayed 

Deceleration Approach)

• MIT has developed analytical framework for assessing 

changes to aircraft speed/thrust/configuration profile; 

e.g., Delayed Deceleration Approach

– Reduce noise by delaying extension of flaps (known fuel 

benefits)

– Must decelerate early enough to ensure stable approach 

criteria

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Under Flight Track Noise by Component, Representative Narrow 

Body Aircraft Approaches with 4,000 ft Level-Off
Federal Aviation

Administration

DDA Noise Assessment

• Engine thrust on approach is relatively 

low  airframe noise components more 

easily heard

• Validation and implementation 

challenges remain

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Federal Aviation

Administration

DDA Challenges

• Operational validation of noise benefit

– Work ongoing to collect aircraft state and noise 

measurement data to support validation of noise 

modeling methodology and identification of low-noise 

behaviors

• Pilot guidance

– Continued discussion with pilots

– Examine DSTs: e.g., DLR Low Noise Augmentation 

System, A350 Flight Management System

• Different deceleration rates for different 

aircraft creates ATM challenge in 

separating/sequencing aircraft

– Continued discussion with FAA ATO, ANG, and AVS

– Current or future ATM tools that could support 

integration?

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Early, Mean and Delayed Deceleration

(B738 arrivals into BOS)
Federal Aviation

Administration

Operational Opportunities for Reduced 

Climate Impact

• Addressing climate change is a national 

(administration) priority

• Past research: Continuous Descent Arrival, 

Cruise Altitude and Speed Optimization, DDA, 

Surface Congestion Management

• New effort: ASCENT-78 Contrail Avoidance 

Decision Support and Evaluation 

• Ongoing coordination (internal/external) on 

operational opportunities for fuel/emissions 

reduction

• Open to ideas/discussion

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(2019)
Summary

• Despite considerable progress in reducing aircraft source noise and 

community noise exposure, aviation noise remains a concern in many areas

• FAA is exploring operational opportunities to reduce the noise from the 

current fleet

• FAA is developing tools to better assess benefits of advanced operational 

procedures, operationally validating and measuring concepts with potential 

to reduce noise, and seeking mechanisms for implementation

• Reducing climate impact through operational efficiencies is also a high 

priority area

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Chris Dorbian

Federal Aviation Administration 

Office of Environment and Energy

Email: christopher.dorbian@faa.gov