The document discusses environmental modeling needs for the Next Generation Air Transportation System (NextGen). It describes how different modeling tools are needed for strategic planning versus tactical planning and research. Integrated models like the Aviation Environmental Design Tool (AEDT) are useful for policy support and inventories, while simulation tools are better suited for evaluating NextGen concepts and advanced vehicle integration. The document outlines several projects integrating AEDT and the Advanced Concept Evaluation System (ACES) to assess environmental impacts of new operational concepts and technologies. Future work could improve the integration of simulation and integrated models to help identify environmental constraints for specific aircraft operations.

1. Environmental Modeling of
NextGen Concepts & Technologies
Jawad Rachami
12 August 2010

2. The Optimization Challenge for NextGen
 New Aircraft Technology
(e.g., FAA CLEEN, NASA ERA)
 Alternative Fuels (CAAFI)
 CNS/ATM Technologies
 NextGen Procedural
Enhancements & Redesign
 Airport Capacity
improvements and strategic
planning
 Multimodal connectivity
 Comprehensive Energy &
Climate policy
 Local zoning and noise
control
 Research Investments
 Incentives for accelerated
adoption of new technology
 Airline Business Model
Realignment (incl. M&A)
 Global Fuel Price Volatility
 Market responses to
economic/security
conditions
 Demand for point-to-point
travel
 Incentives for accelerated
adoption of new technology

3. The Environmental Challenge for NextGen
Science & Tools:
 Defining climate forcing effects from aircraft operations
 Enhancing prediction accuracy of cruise emissions
 Defining airport contributions to local Air Quality
 Developing environmental Interdependency metrics and tools for both
tactical and strategic planning
Policy / Regulatory:
 Agreement on climate controls and environmental standards for aviation
 Tradeoffs between local land-use issues and system-level emissions /
energy efficiency policy goals
 Environmental Justice and NEPA process
User/Stakeholder Issues:
 Environmental effects of increased NAS capacity
Airport residential encroachment
Business case for fleet renewal and technology adoption
 Market response to carbon pricing
 Viability of biofuels and implications for land-use
FAA Goals & Approach
Source: FAA/AEE 2010

4. Future Capacity vs. Environment
 Demand for air travel will increase; hence, the need for higher capacity and
operational frequency
 Without game-changers, the environmental footprint of the NAS will increase
Source: FAA/AEE 2010

5. NextGen Environmental Modeling:
Different Needs Require Different Tools
Applications –e.g.:
 Policy Support
 NAS Inventories
 NEPA Compliance
 Airport Planning programs
General Approaches / Tools:
 Integrated Models (e.g., AEDT)
 GHG Inventories
 Average long-term exposure metrics
 Defined Mitigation guidelines for areas of “significant
impact”
Strategic Planning Tactical Planning & Research
Applications-e.g.:
• NextGen Concept Integration
• Airspace Management
• Advanced vehicle research
Needed Approaches / Tools:
 Integrated Simulation Tools
 Interdependency/tradeoff metrics
 Optimization techniques based on spatial and
temporal factors

6. NASA NRA: Introduction of Advanced
Vehicles & Concepts in NextGen

7. Model Integration
We set up AEDT (FAA) and ACES (NASA) on a BLIND date!
AEDT + ACES

8. Environmental Modeling Approach
ACES 6.0 /
ACES-KTG AEDT
Taskmaster
AAM/AMM
(Noise)
Impact & Tradeoffs Metrics
Operational Attributes
– i.e.:
• 4DT equipage
• Airside reqs.
• Spacing req.
• Etc.
AEDT/AEM
(Emissions)
Air Quality
Assessment
Key Vehicle Attributes:
• Environmental
Source Data
•Performance Data
• Operational Data
PCBoom
AEDT/APM
Data Pre-
Processor
Sonic
Boom
GCAM /EBME
(System-wide Noise)
• A comprehensive approach to system-wide
environmental modeling using current-state models
and Tools
• Successful data integration between ACES and two
key models: AEDT and PCBoom.

9. Forecast NextGen 2025 Emissions
BJ
3%
RJ
4%
GA
4%
Integrated CO2
Emissions Incl.
International =
1,387,928 MT
CTP
0.4%
HJ
49%
LJ
35%
 Estimated US GHG (CO2) in NextGen 2025 ~ 337 million metric tons annually (4.8% higher than current
total US GHG) without alternative fuels or accelerated adoption of new aircraft technology.
 The US emissions dominated by two market segments / vehicle classes:
• Medium-haul single aisle (B737-like vehicle class)
• Long-haul twin-aisle (B777-like vehicle class)
Integrated NOx
Emissions Incl.
International =
5,884 MT
LJ
33%
HJ
57%
BJ
2%
RJ
3%

10. Spatial & Altitude Distribution of NAS-Wide Emissions
•Center boundaries reflect existing airspace architecture and do not reflect NextGen plans for 2025 airspace
redesign.
•Spatial distribution at 10km resolution and takes into account both cruise and LTO emissions

11. System-Wide Noise Analysis
 Increases in noise exposure at regional airports due to the introduction of point-to-point on-demand
operations
 Small decreases (<5%) noted at various primary airports due to intro of advanced vehicles

12. System-Wide Noise Analysis
Integration of advanced vehicles into NextGen
baseline created minimal increase in noise
exposure within NORCAL TRACON
DNL
NORCAL
Baseline
Area (sq.mi)
NORCAL
Integrated
Area (sq.mi)
Change
> 55dB 307 315 2.7%
> 65dB 61 63 3.2%

13. NAS-wide Sonic Boom Analysis:

14. Takeaways from NextGen NRA
 The dominant sources of NAS-wide emissions are the single-aisle/medium-haul and
twin-aisle/long-haul vehicle classes
 System-wide Emission reductions are possible through intro of advanced vehicles and
subsequent fleet optimization in single-aisle and twin-aisle classes.
 Rate of market adoption is key to benefit realization
 Biofuels have the potential of acting as a game-changer, but several issues/challenges
remain
 Noise is a local constraint that can hamper implementation of otherwise system-level
efficient concepts
 A combination of both advanced procedures and advanced aircraft technologies are
necessary to tap into system efficiencies without causing adverse noise impacts on
the ground
 Need higher fidelity terminal modeling to better understand local noise constraints
resulting from new trajectories, consolidated corridors, and super density operations

15. NASA SBIR: Integrated Testbed of
Environmental Analysis of NextGen
Concepts Using ACES

16. Model Integration
We set up AEDT and ACES on a SECOND date!
AEDT + ACES

17. Project Overview
• Investigative Team: IAI-Wyle
• Objective: Assess modeling technology allowing combined
performance and environmental assessments for new NAS concepts
using ACES
• Project tasks:
– Task 1. Conduct a trade study to evaluate NAS existing environmental tools.
– Task 2. Define the modeling framework and associated environmental and performance tools,
specifically targeting the integration of ACES and AEDT.
– Task 3. Develop modeling strategies for improving the performance/environmental assessment state of
the practice in several key areas:
• Deterministic trajectory generation—change to stochastic trajectory computation so that variances in
intended/actual trajectories can be accounted.
• Runway-to-runway trajectory generation—ensure that performance models can compute high precision trajectories
from runway-to-runway.
• Mixed equipage analysis—develop a strategy so that evaluation of a transition period where mixed-equipage issues
dominate can be performed.
– Task 4. Configure ACES for modeling two advanced concepts as directed by the NASA COTR.
– Task 5. Conduct the integrated performance/environmental study of airborne M&S at ATL.
– Task 6. Document the results.

18. ACES-KTG Terminal trajectories
 Assess the trajectories generated by the ACES
Kinematic Trajectory Generator (KTG)
– KTG ground track data from wheels-up to wheels-on
was found to be sufficient and exceeds the
precision necessary for AEDT
– KTG does not provide any data for on-ground
segments, which can be important to
environmental assessments.
 KTG and AEDT/INM use two different sources for
profile data, BADA and SAE-1845, respectively.
 Altitude: KTG altitudes show a more gradual climb
rate than AEDT. KTG altitudes on arrival are
consistent with AEDT
 Speed: Accelerations along the profiles occur at
approximately the same track distances
 Fuel burn: Fuel Burn rate showed a high level of
agreement

19. Project Takeways to Date (still ongoing)
• A number of issues were uncovered with both
ACES and AEDT, all solved during the project
• ACES capable of assessing impacts of changes to
airport capacities, STAR-SID procedures etc
• Future scenarios with advanced airspace
technologies such as merging and spacing on
noise and emissions can be tested in a
straightforward manner
• AEDT capable of computing noise and emission
studies for large data sets quickly

20. Potential Future Enhancements
environmental modeling of NextGen
Concepts & Technologies

21. Model Integration
Should there be a 3rd Date?
Is this a casual relationship or a potential marriage?
AEDT + ACES
Well, It depends!

22. It depends what we need to achieve:
– Overall inventories/impacts based on a predefined operational end-state
OR
– Research of optimum alternatives for NextGen concepts both
strategically and tactically

23. Different Needs Require Different Tools
Applications –e.g.:
 Policy Support
 NAS Inventories
 NEPA Compliance
 Airport Planning programs
General Approaches / Tools:
 Integrated Models (e.g., AEDT)
 GHG Inventories
 Average long-term exposure metrics
 Defined Mitigation guidelines for areas of “significant
impact”
Strategic Planning Tactical Planning & Research
Applications-e.g.:
• NextGen Concept Integration
• Airspace Management
• Advanced vehicle research
Needed Approaches / Tools:
 Integrated Simulation Tools
 Interdependency/tradeoff metrics
 Optimization techniques based on spatial and
temporal factors

24. Model Integration
There are inherent limitations to the integration of Simulation
models and Integrated Models
Integrated
Models
+ Simulation
ACES
TAAM
SIMM
OD
AEDT
Noisem
ap
EDMS
NIRS
INM

25. Model Integration
There are inherent limitations to the integration of Simulation
models and Integrated Models
+ Simulation
ACES
TAAM
SIMM
OD
Simulation
DOD/
AAM
NPS/
NMSi
m
Sim-to-Sim is important to identify environmental constraints within a
4D environment for aircraft- and trajectory-specific operations

26. Example: Noise Simulation

27. Detailed modeling of advanced vehicle features
• Of advanced aircraft concepts such
as engine shielding and other
complex design features
• Nonlinear propagation effects and
noise levels in the time domain and
with a variety of integrated metrics
• Advanced modeling of helicopter
and tiltrotor operations
• Sources defined as three-dimensional
one-third octave band
spectra

28. QUESTIONS