Research Projects

Identifying Viable Techniques for Modifying NextGen Flight Track Design to Reduce Community Noise Exposure and Annoyance In Reserve

Assigned to salverson@esassoc.com
Last Edited by Mike Salamone

This research would examine several examples where implementation of Metroplex or other procedures has resulted in widespread increased community complaints and would explore options for redesigning those flight tracks to reduce noise concentrations over noise sensitive areas while satisfying project design goals and constraints. Changes in aircraft noise exposure, fuel consumption, and air emissions would be quantified and would be compared to the pre- and post-Metroplex conditions.

 

The research would produce recommendations for the implementation of viable techniques for reducing community noise exposure while maintaining, to the greatest extent practical, the benefits of NextGen flight procedures for FAA's consideration in flight procedure development moving forward.

Background (Describe the current situation or problem in the industry, and how your idea would address it.)

With the implementation of NextGen procedures through the Federal Aviation Administration's (FAA) Metroplex and related processes, some communities have expressed concern regarding increased aircraft noise exposure resulting from the concentration of aircraft flight tracks caused by the implementation of some Performance-Based Navigation (PBN) flight procedures. Multiple law suits have been filed and in one case, the FAA has been directed by the Courts to return to the pre-Area Navigation (RNAV) flight procedures; negating the expected benefits of reduced fuel consumption and reduced air emissions.

The FAA has publicly stated that the implementation of PBN across the entire National Airspace System (NAS) is a key NextGen goal. PBN is a critical enabler of Trajectory-Based Operations (TBO), which is intended to reduce delays in the NAS through increased operational predictability. Implementation of PBN could continue to concentrate aircraft flight tracks and aircraft noise over noise sensitive areas. The research effort proposed in this idea would leverage existing FAA and The MITRE Corporation (MITRE) research into PBN design techniques that could reduce concentration of aircraft noise while maintaining the benefits gained through the creation of predictable and repeatable flight tracks and procedures in the NAS. These techniques include vectors to initial fixes (IFs), open Standard Instrument Departures (SIDs), and other terminal-area PBN procedure design techniques.

Approach (Describe in general terms the steps you think are needed to achieve the objective.)

With the implementation of NextGen procedures through the Federal Aviation Administration's (FAA) Metroplex
and related processes, some communities have expressed concern regarding increased aircraft noise exposure
resulting from the concentration of aircraft flight tracks caused by the implementation of some Performance-
Based
Navigation (PBN) flight procedures. Multiple lawsuits have been filed and in one case, the FAA has been directed by
the Courts to return to the pre
-Area Navigation (RNAV) flight procedures; negating the expected benefits of reduced
fuel consumption and air emissions.
The FAA has publicly stated that the implementation of PBN across the entire National Airspace System (NAS) is a
key NextGen goal. PBN is a critical enabler of Trajectory
-Based Operations (TBO), which is intended to reduce
delays in the NAS through increas
ed operational predictability. Implementation of PBN could continue to
concentrate aircraft flight tracks and aircraft noise over noise sensitive areas. The research effort proposed in this idea
would leverage existing FAA, and The MITRE Corporation (MITRE
) research into PBN design techniques that
could reduce concentration of aircraft noise while maintaining the benefits gained through the creation of predictable
and repeatable flight tracks and procedures in the NAS. These techniques include vectors to in
itial fixes (IFs), open
Standard Instrument Departures (SIDs), and other terminal
-area PBN procedure design techniques.
This research would draw upon existing situations where implementation of Metroplex or non-
Metroplex PBN
projects has resulted in widespread increased community complaints and would analyze potential alternate flight
track designs that may reduce concentration of noise over noise sensitive areas while satisfying project design goals
and constraints, including existing FAA policy and order
s. A key focus area of the project would be the types of land
use overflown by the flight procedures as well as analysis of typical community expectations related to overflight
frequency and concentration. Changes in aircraft noise exposure, fuel consumpti
on, and air emissions would be
quantified and would be compared to the pre
- and post
-implementation conditions for the original project. For noise,
several metrics will be computed:

Day
-Night Average Sound Level (DNL)

Sound Exposure Level (SEL) for selected single flight events

Time above a given noise level (TA)

Number of events above a given noise level (NA)
The research would produce recommendations for the implementation of viable techniques for reducing community
noise exposure while maintaining, to the greatest extent practical, the benefits of NextGen flight procedures for
FAA's consideration in flight procedure development moving forward. The ultimate goal of the research is to provide
concrete strategies that airport authorities can use for discussing flight procedure design with the FAA during the
design process, to avoid community controversies that may result from the implementation of flight track changes.

Cost Estimate and Backup (Provide a cost estimate and support for how you arrived at the estimate.)

The following describes the key project roles, the justification for that role in conducting the research, and the
estimated cost by role concluding with the estimated total cost for this research effort.
Role: Project Manager
Justification: Provides oversight of the project and applies strategic and FAA policy expertise for quality assurance
review of project deliverables. Leads client
-facing interactions.
Estimated Cost: $20,000
Role: Policy Analyst
Justification: Reviews existing FAA orders and policies relevant to flight procedure design and community outrea
ch.
Also reviews previous work related to flight procedure design and environmental impacts. Synthesizes information to
determine flight procedure design opportunities and constraints.
Estimated Cost: $60,000
Role: Noise Modeler
Justification: Performs noise, emissions, and fuel consumption modeling for air traffic project pre-implementation and post
-implementation scenarios as well as alternate flight track designs.
Estimated Cost: $60,000
Role: Land Use Analyst
Justification: Analyzes land use within ai
r traffic project vicinities, to support the design of alternate flight
procedures. Converts noise modeling results into population and land use exposed to different levels of noise.
Estimated Cost: $60,000
Total Estimated Research Effort Cost:
$200,000
Assumptions:

Publicly
-available FAA orders, policy documents, and research will be leveraged by the policy analyst.

Existing environmental model files for FAA projects will not be made available to the project team, so
simplified pre- and post-implementation study files will have to be developed.

Related Research - List related ACRP and other industry research; describe gaps (see link to Research Roadmaps above), and describe how your idea would address these gaps. This is a critical element of a synthesis topic submission.

There are a number of publicly available research documents and project documents that are related to NextGen
flight procedure design and community outreach. These are listed below, along with the unique contributions of this
proposed project.
ACRP 02
-12: Environmental Optimization of Aircraft Departures: Fuel Burn, Emissions, and Noise
This ACRP project, completed in 2013, looked at the environmental implications of a variety of flight procedure
design techniques that could alter noise exposure to communities, including (but not limited to) alternate ground
tracks, flight track dispersion ("fanning"), RNAV/Required Navigation Performance (RNP) overlays of conventional
departure
s, preferential routing for low
-noise jet aircraft, and the use of different flight procedures at different times.
The project also developed a departure procedure environmental optimization tool. While case studies were included,
the project contained very little analysis of the relationships between flight procedures, land use, and community
preferences. The project proposed in this problem statement would focus on these relationships to inform the design
of alternate flight procedures.
ACRP Report 150: NextGen for Airports, Volume I (Understanding the Airport's Role in Performance Based
Navigation) and II (Engaging Airport Stakeholders)
These ACRP volumes, completed for ACRP projects 03
-34 and 01-
28 (respectively), discuss the relationships
between airports and the FAA's NextGen initiative and also describe stakeholder engagement related to NextGen.
Volume I, in particular, describes FAA PBN development processes and where airports can potentially engage with
the FAA. While the volumes give examples of stakeholder interaction, it does not provide flight procedure design
strategies. The project proposed in this problem statement would focus on flight procedure design strategies.
FAA Initiative to Address Noise Concerns of Santa Cruz/Santa Clara/San Mateo/
San Francisco Counties, Phase Two
This initiative was launched by the FAA to address noise concerns of certain northern California counties that were
raised as a result of Northern California Metroplex implementation. It contains extensive analysis of pro
posed
alternate flight procedures, including FAA initial responses to the proposals. It does not contain details on how the
procedures were determined. The project proposed in this problem statement would utilize analysis of land use and
community preferences to propose a structure for determining flight procedures designs.
Aviation Sustainability Center (ASCENT) Project 23, Analytical Approach for Quantifying Noise from Advanced
Operational Procedures
The FAA's Aviation Environmental Design Tool uses noise modeling assumptions that limit the flexibility for
modeling the noise effects of changes in flap settings, landing gear deployment schedules, and approach/departure
speeds. ASCENT Project 23 is investigating analytical techniques for determining the noise effects of such strategies.
One of the project's outcomes is an analytical method suitable for implementation in AEDT, but the FAA is not
required to adopt any method that comes from the project. The project proposed in this problem statement would
focus on flight procedure design techniques that are appropriate for AEDT's current level of fidelity.

Annotations
Idea No. 41