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National Aeronautics and Space Administration 

Airspace Systems Program
 

A quarterly update of accomplishments and upcoming activities from NASA’s Airspace Systems Program. 

APRIL—JUNE 2010
 

Technical/Programmatic Highlights
 

Dynamic Airspace Configuration: Article 1 Traffic Flow Management: Articles 9, 10
 

Functional Allocation: Article 2 Trajectory Prediction/Separation Uncertainty: Article 11
 

Integrated Test & Evaluation: Article 3 Partnership Research: Article 12
 

Safe & Efficient Surface Operations: Articles 4, 5, 6 Operational Traffic Management Advisor (TMA): Article 13
 

Super Density Operations: Articles 7, 8
 

www.nasa.gov See inside for details 
Technical/Programmatic Highlights
 

1 Dynamic Airspace Configuration 

Research Transition Team 

Meeting, March 2010, NASA’s 

Ames Research Center 

Details: Representatives from the FAA, 

MITRE, JPDO, and NASA gathered to discuss 

recent Dynamic Airspace Configuration 

(DAC) research and next steps for research 

transition. NASA received positive feedback on 

proposed research directions for flow corridors, 

flexible airspace, and generic airspace. Flow 

corridors enable high density traffic along 

compact corridors of airspace by segregating 

the corridor operations from surrounding 

airspace. NASA flow corridor research focuses 

on identifying volumes and percentages of 

aircraft equipage at which corridors allow a 

significant reduction in resolution maneuvers. 

NASA’s flexible airspace research focuses on 

the benefits of modifying airspace boundaries 

in response to fluctuations in demand due to 

volume changes or reroutes around weather. 

The FAA suggested focusing this research on 

interactions with Traffic Flow Management. 

NASA’s generic airspace research recently 

completed a human-in-the-loop experiment 

showing how NextGen automation tools allow 

controllers to manage unfamiliar airspace 

with only a minor workload increase. The 

FAA suggested studying how well controllers 

could manage unfamiliar airspace with mixed 

equipage operations or dynamic airspace 

operations. NASA DAC research continues 

to be reflected in the FAA’s National Airspace 

and Procedures Plan, which is to be released 

in September 2010. When complete, NASA 

will present results of its planned research at a 

follow-on meeting hosted by MITRE, or the 

FAA Technical Center. 

2 Coordinated experiment of an 


Automated Separation Assurance 


Human-In-The-Loop simulation 


successfully completed at NASA’s Ames 

Research Center and NASA’s Langley 

Research Center, February-March 2010 

Details: Researchers simulated an advanced 

operational concept of the Next Generation 

Air Transportation System (NextGen) using 

an Automatic Dependent Surveillance 

Broadcast (ADS-B) enabled operation, selfseparation and 4D trajectory-based operations 

at approximately two-times current air traffic 

control maximum capacity. This experiment 

achieved unprecedented commonality between 

Ames and Langley experiment designs for 

comparing disparate concepts. It matured 

flight-deck automation technology and was 

sponsored by the NextGen Airspace and 

Concepts & Technology Development Project 

of NASA’s Airspace Systems Program. The 

Langley SA HITL experiment was paired with 

an Ames SA HITL experiment to investigate, 

through a jointly developed experiment 

commonality plan, different allocations of 

the traffic separation function of Air Traffic 

Management (ATM). The Langley experiment 

modeled a distributed airborne allocation of 

separation assurance using airborne selfseparation capability, whereas the Ames 

experiment modeled a centralized ground-based 

allocation using trajectory data link capability, 

with both concepts relying heavily on 

Automatic Dependent Surveillance Broadcast 

(ADS-B) for surveillance and automated 

functions for conflict detection and resolution. 

Both concepts reflect the Next Generation 

Air Transportation System (NextGen) focus 

on 4D trajectory-based operations, and the 

experiments contribute to NASA’s charter to 

research ATM function allocation for the Joint 

Planning and Development Office (JPDO). 

The experiments were coordinated to address 

the challenges in producing comparable results 

of disparate concepts represented at medium 

human-in-the-loop fidelity across disparate 

simulation platforms. 

The Ames study on Ground-Based Automated 

Separation Assurance was conducted in the 

Airspace Operations Laboratory (AOL). 

Two primary air traffic control rooms were 

configured with ten test positions (eight 

controllers plus two supervisors) and produced 

220 hours of data from the ten positions each 

working a total of 22 hours. Current FAA 

controllers and supervisors, as well as recently 

retired controllers, worked advanced NextGen 

workstations in the primary test sectors 

and support positions for the surrounding 

airspace. Ten simulation pilots managed 

the aircraft for this simulation. In complex 

traffic scenarios of 15-minute, 30-minute and 

three-hour durations, controllers interacted 

with advanced technologies for ground-based 

separation assurance, weather avoidance and 

arrival metering to manage much higher 

traffic densities than currently experienced 

in the National Airspace System. During the 

simulation, traffic densities in some sectors 

were increased to more than 50 aircraft. For 

comparison, in today’s system these sectors are 

configured to handle no more than 18 aircraft. 

The current approach to separation assurance 

at these high traffic levels is centered on 

sophisticated ground-based automation, which 

conducts routine operations, performs standard 

separation assurance tasks and provides a 

safety net. When more complex situations 

arise, controllers step in to make decisions and 

manage the automation. 

Researchers in the Crew Systems and Aviation 

Operations (CSAOB) Branch at Langley have 

completed data collection for a simulation 

experiment of airborne self-separation. The 

Separation Assurance Human-in-the-Loop 

(SA HITL) experiment was conducted in the 

Air Traffic Operations Laboratory (ATOL) 

and involved 48 commercial airline pilots 

from the U.S. and Europe flying scenarios 

of high traffic density in simulated en-route 

airspace. The Langley experiment collected 

264 pilot-hours of data across 14 scenarios 

simulating traffic densities up to two times 

today’s traffic capacity. Pilot procedures 

included resolving traffic conflicts and 

adjusting trajectories to meet assigned arrival 

schedules. Independent variables included 

traffic density, the presence of arrival time 

constraints, and the timing of arrival delay 

assignment. Arrival delays requiring path 

changes were issued at either disbursed or 

synchronous times to investigate operational 

agility. In a first for Langley ATM experiments, 

one of the four subject groups included nine 

European pilots to support a global perspective 

on ATM research. The results of this and 

future studies on function allocation are 

expected to influence the direction of far-term 

operations in NextGen and beyond. 

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Research Events 

and Activities 

•	 Jun. 1-30: Separation Assurance with 

FANS-1 /A Automated Resolution 

Implementation, NASA Ames 

•	 Jun. 8: Merging & Spacing/Interval 

Management (IM) Working Group 

•	 Jun. 8-10: Closely Spaced Parallel 

Operations (CSPO) Working Group, 

Washington, DC 

•	 Jun. 8-11: ACES Workshop, NASA Ames 

•	 June 10: NASA/FAA NextGen V&V 

Technical Interchange Meeting, FAA Tech 

Center Atlantic City 

•	 Jun. 13-18: ADS-B Requirements Focus 

Group (RFG) Working Group (RTCA-186 

and EuroCae WG-51), FAA Tech Center, 

Atlantic City 

•	 Jun. 14-Jul. 2: Generic Airspace Phase 4 

HITL Experiment Study, NASA Ames 

•	 Jun. 21-Jul. 9: Terminal Area Procedures 

for Paired Approaches Runways (TAPPR) 

Experiment 2, NASA Ames 

•	 Jul. 27-29: Generic Airspace Phase 4 HITL 

Experiment, NASA Ames 

•	 Aug. 2-5: AIAA Guidance, Navigation and 

Control Conference 

•	 Aug. 2-5: AIAA Modeling and Simulation 

Technologies Conference 

•	 Aug. 10-19: Flexible Airspace II Experiment, 

NASA Ames 

•	 Sep. 8-9: Green Aviation Conference, 

NASA Ames 

•	 Sep. 13-15: AIAA Aviation Technology, 

Integration and Operations Conference 

•	 Sep. 19-24: International Council of 

Aeronautical Sciences (ICAS) 2010 

3 Successfully completed human-inthe-loop simulation of the Efficient 

Descent Advisor (EDA), April 2010, 

NASA’s Ames Research Center 

Details: A simulation of the Efficient Descent 

Advisor (EDA) was successfully conducted in 

the Crew-Vehicle Systems Research Facility 

(CVSRF) using the air traffic control simulation 

laboratory and the Boeing 747-400 cockpit 

simulator. The primary objectives were to 

evaluate secondary advisories to correct for 

predicted arrival-time errors induced by 

trajectory-prediction uncertainty and/or 

flight technical error, and also to study cruisealtitude advisories used for resolving conflicts 

with over-flight traffic. Data was collected to 

assess automation performance and controller 

acceptability under varying EDA configurations 

and traffic loading. Three controllers from 

Denver Center were rotated through three 

adjacent arrival sectors. The Boeing 747 

simulator (flown by pilots from United Airlines 

and Cathay Pacific) was included in each 

simulation scenario to evaluate how EDA 

advisories impact the flight deck, and the time 

required by crews to enter EDA clearances into 

airborne automation systems. Observers over 

the four-day simulation included subject-matter 

experts from Boeing, MITRE, the Federal 

Aviation Administration and the National Air 

Traffic Controllers Association. Data analysis 

is underway. 

4 High-fidelity simulation 

environment built for Surface 

Advisory Tool Experiment, March 

2010, NASA’s Ames Research Center 

Details: A high-fidelity Human-in-the-Loop 

(HITL) simulation environment was successfully 

built, thus forming the foundation for conducting 

research in the airport surface domain. The Spot 

and Runway Departure Advisory (SARDA) 

tool was tested as a possible near-term decision 

support tool for tower controllers to enhance the 

efficiency of surface traffic. Two optimization 

algorithms were developed: 

•	 Spot Release Planner (SRP) – provides

the ground controller with optimum spot 

release sequences and times that reduce 

taxi delay while maintaining maximum 

runway throughput. 

•	 Runway Scheduler (RS) – provides local

controllers with runway departure 

sequence advisories as well as arrival 

runway crossing advisories. 

Human factors researchers investigated 

controller interactions with the tool and 

usability of the algorithms, followed by a data 

collection simulation. 

5 Third surface optimization 

NRA Workshop, January 2010, 

San Jose State University 

Details: Two NRA teams led by San Jose 

State University and the Georgia Institute 

of Technology presented their results on the 

development of surface optimization algorithms 

and the integration of those algorithms into 

simulation software platforms. The NASA 

team discussed the human-in-the-loop surface 

simulation of the Spot and Runway Departure 

Advisory (SARDA) tool that was completed in 

December 2009, as well as results from their 

surface optimization algorithms. The SARDA 

human-in-the-loop experiment is to provide 

an optimal sequence and timing for releasing 

departure aircraft from spots to the ground 

controller. The objective is to increase the 

departure runway throughput while reducing 

the runway queue size and minimizing taxi 

time by controlling spot release times of 

departure aircraft. Third-year goals of these 

NRA activities are to 1) improve robustness of 

the surface algorithms, 2) integrate algorithms, 

and 3) implement their algorithms into NASA’s 

Surface Management System (SMS), which is 

a real-time simulation platform. The NASA 

team presented the new modular and extensible 

architecture of SMS software, from which 

the NRA teams showed a great interest in 

collaborating with NASA to implement their 

optimization algorithms for further evaluation 

on a common platform. 

Continued on page 4 

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6 Third Environmental NRA 

Workshop, February 2010, NASA’s 

Ames Research Center 

Details: The NRA team led by Metron 

Aviation presented results of emissions 

and noise computations based on their 

Environmental Planner tool. Attendees included 

researchers from Metron Aviation, George 

Mason University, NASA, and UARC. The 

Environmental Planner uses emissions, noise, 

and/or fuel in an optimization algorithm to 

reduce environmental impacts while achieving 

efficient surface operations. Third year goals 

of this NRA activity are to 1) refine the 

Environmental Planner algorithms, 2) conduct 

extensive sensitivity analyses with varying 

environmental and operational parameters, 

and 3) develop a high level design of system 

architecture with input/output specifications of 

each component in the system. 

7 Second simulation completed for 

Terminal Area Paired Procedures 

Research (TAPPR), March 2010, 

NASA’s Ames Research Center 

Details: The Terminal Area Paired Procedures 

Research (TAPPR) concept focuses on the 

delivery of aircraft pairs, one plane five to 25 

seconds in trail of the other, to a coupling point 

12 nautical miles from the runway threshold. Air 

traffic controllers have recommended that this 

type of decision support tool would be of value 

today during Simultaneous Offset Instrument 

Approach (SOIA) operations. Preliminary results 

show that most pairs met the timing constraint 

at the coupling point. This concept allows paired 

landings to closely-spaced parallel runways during 

Instrument Flight Rules conditions—furthering 

the NextGen goal of increasing the capacity 

of airports in all weather conditions. In this 

experiment, enhancements to the timeline display, 

pairing logic, and conformance monitoring were 

made using experimental data and participant 

feedback from the first TAPPR experiment. 

The experiment consisted of three levels of 

automation: 1) manual determination and 

management of pairs; 2) automated assistance to 

controllers in creating and managing pairs; and 3) 

more automated assistance in evaluating, selecting 

and managing pairs, as well as an automated 

pairing algorithm to assist in determining the best 

pairs. Controllers made effective use of timeline 

guidance for pairing in the TRACON sectors 

and considered it a useful aid. In the first TAPPR 

experiment the controllers preferred the second 

level of automation. However, in this experiment, 

which included enhancements to the decision 

support tool, the highest level of automation was 

preferred. A conformance window was available 

on the controller display and this enabled the 

controllers to monitor the status of the trailing 

aircraft with respect to the timing constraint 

at the coupling point. The third experiment is 

scheduled for June/July 2010. 

8 Analysis of performance and 

feasibility of the Simplified Aircraftbased Parallel Approach (SAPA) 

Concept, March 2010, NASA’s Langley 

Research Center 

Details: SAPA is one of the advanced concepts 

being considered for dependent, low-visibility 

operations for dual and triple runways spaced 

closer than 2,500 feet. For runways with 

centerline spacing closer than 2,500 feet, wake 

turbulence encounters between aircraft on parallel 

paths becomes problematic and dependent 

operations are required. At the request of the FAA, 

NASA performed an initial system study of the 

SAPA concept to assess operational benefits and 

constraints plus a preliminary technical feasibility 

analysis. While this assessment is preliminary, 

it has shown the basic SAPA concept to be 

technically and operationally feasible. An example 

implementation of the concept was developed in 

some detail, including identification of potential 

pilot/controller roles and responsibilities. Several 

design and implementation issues were explored, 

which should be useful to aid the FAA in the 

development and refinement of the SAPA 

concept. This effort was jointly funded by the 

FAA and the Airspace Systems Program. A white 

paper has been written to summarize this detailed 

study, and is in the process of being thoroughly 

reviewed within NASA with the intention of 

it being turned into a formal NASA Technical 

Memorandum (TM). Follow-on studies are being 

sought with our FAA customer to more fully 

explore the design space suggested by this concept 

of operations for closely spaced parallel runways. 

Research Events and 

Activities Continued 

•	 Sep.: Collision Avoidance for Airport Traffic 

(CAAT) Fast-Time Simulation Study, NASA 

Langley 

•	 Oct. 3-7: 29th Digital Avionics Systems 

Conference (DASC) 

•	 Oct. 6-7: ASP Users Forum 

•	 Oct. 11-22: Trajectory-based Operations 

with Datacom Simulation, NASA Ames 

•	 Oct.: Separation Assurance Dynamic 

Weather Batch Study, NASA Langley 

•	 Nov.: En Route Descent Advisor / 

3D Path Arrival Management Experiment, 

NASA Ames 

2011 

•	 Mar.: ASP Technical Interchange Meeting 

About This Newsletter 

The Airspace Systems Program issues this 

quarterly newsletter to report on completed 

research activities and to provide a record of 

current and upcoming events of interest to the 

community. If you have questions about any of 

the information in this issue, please contact John 

Cavolowsky at NASA-ASP@nasa.gov. 

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9 Simulation of market-based 


system for prioritizing flights shows 


promise among airline dispatchers, 


January 2010, NASA’s Ames Research Center 

Details: An experiment using Credit-based User 

Preference System (e-CUPS) was conducted 

to evaluate a system for prioritizing flights 

traveling through congested airspace. e-CUPS 

allows airline dispatchers to specify their high 

priority flights by assigning them credits, which 

are allocated to dispatchers according to their 

number of flights. The system gives flights with 

the most credits their requested departure times 

and routes. Flights with fewer credits may be 

delayed or re-routed to alleviate congestion. To 

evaluate the system’s feasibility and benefits, 

five airline dispatchers from American Airlines, 

AirTran Airways, Continental Airlines, 

Southwest Airlines, and United Airlines used 

the system to manage a set of flights through 

several simulated air traffic scenarios. A recently 

retired air traffic manager set constraints on 

airspace capacities. Data and post-experiment 

surveys indicated that dispatchers successfully 

distributed delays among their flights based on 

their priorities. Their priorities mainly consisted 

of maintaining schedule integrity, minimizing 

fuel consumption, and preserving flight 

connectivity. To make future experiments more 

realistic, participants suggested constraining 

airport arrival and departure rates and more 

realistically simulating weather, along with other 

enhancements. The next experiment is planned 

for the fall of 2010. 

10 Accelerating FACET simulations 

March 2010, NASA’s Ames 

Research Center 

Details: Optimal Synthesis wrapped up a 

Phase II SBIR and kicked-off a Phase III SBIR 

on the same topic: accelerating Future ATM 

Concepts Evaluation Tool (FACET) simulations. 

Their work on a Computational Appliance for 

the Rapid Prediction of Aircraft Trajectories 

(CARPAT) has produced a hardware-software 

co-design that is capable of predicting trajectories 

nearly 200 times faster than was previously 

possible. For Phase III they will be developing 

code that will ease the use of the tool for 

researchers in Traffic Flow Management. The 

tool’s power also will be demonstrated through 

an experiment involving dozens to hundreds of 

FACET simulations to measure the effects of 

uncertainty in TFM. Phase III was made possible 

through the use of Recovery Act funds. 

11 Trajectory uncertainty modeling 

capability now available for 

fast-time simulations, March 

2010, NASA’s Ames Research Center 

Details: A major enhancement to the Airspace 

Concepts Evaluation System (ACES), the fasttime testbed for large-scale simulations was completed the last week of March. The new capability 

incorporates realistic trajectory uncertainties into 

the ACES trajectory prediction. The software now 

allows for parametric variation of cruise speed, 

aircraft weight, top-of-descent point, and decent 

profile uncertainty. These enhancements open an 

important new avenue of research into the effects 

of trajectory prediction uncertainty on the performance of automated separation assurance tools. 

12 NASA/FAA Data Comm experiment completion, March 2010, 

NASA’s Langley Research Center 

Details: NASA Langley planned and conducted 

a human-in-the-loop simulation experiment 

for the FAA Data Comm Project. The purpose 

of the experiment was to investigate the 

acceptability of data communications (data 

comm) in the Terminal Maneuvering Area, as 

well as investigate issues of crew trust in data 

comm during rare events. Data collection for 

the experiment was completed in mid-March. 

Twenty-two current and qualified Airline 

Transport Pilots operated a Boeing 757-200 

simulator Integration Flight Deck (IFD) in 

a high-fidelity replication of Boston (KBOS) 

airspace, and the associated airport runways, 

taxiways, and terminal gate areas. Operations 

included both arrivals to, and departures from, 

Boston, with the research focusing on data 

link-taxi-in and data link-taxi-out instructions. 

Researchers varied communications modality 

(voice, data link) and graphical display 

methodology (paper airport diagram, moving 

map display, with and without depicted routes). 

The simulation also included scenarios to 

examine the effects of rare events on crew trust. 

The simulation included a ten oculometer eye 

and head tracking system, believed to be the first 

(and most capable) of its kind in the world. This 

allowed quantitative measurements of head and 

gaze vectors as a function of time throughout 

the experiment, but without the requirement 

for head-mounted equipment on the crew. 

Simulation scenarios involved multiple arrival 

and departure scenarios, using established KBOS 

procedures, for 21 scenarios per crew, providing 

231 runs for the experiment. Significant new 

capabilities were added to the simulator for this 

experiment, including the ability to generate 

the approximately 200 traffic aircraft, as well as 

develop scenario scripts to control all research 

aspects of the scenario, outside the IFD. Crew 

response to the scenario realism, capabilities 

indicated by the systems and equipment 

simulated, and operational potential for data 

comm in the simulated environment, was 

positive. Data analysis is ongoing and will result 

in a final report. 

13 Operational Traffic Management 

Advisor (TMA) data supports
 

NASA research, April 2010,
 

NASA’s North Texas Research Station (NTX)
 

Details: For nearly 15 years, NASA air traffic 

management research has benefitted from a 

TMA prototype in operational use at the FAA’s 

Fort Worth Air Route Traffic Control Center 

(ARTCC). NASA researchers have collected 

data from the TMA system and have found that 

the operational TMA data provides unique Air 

Traffic Control (ATC) status, intent and action 

information not available from other sources. The 

NASA TMA prototype at Fort Worth ARTCC 

has recently been replaced by a production TMA 

system deployed under the FAA’s Time Based 

Flow Management (TBFM) program. NASA and 

the FAA have jointly developed the Operational 

TMA/TBFM Repository (OTTR) system, 

which replaces and expands on the data analysis 

capabilities of NASA’s TMA prototype. Hosted 

at NTX, OTTR processes raw data collected by 

the FAA from operational TMA systems at all 

20 ARTCCs in the nation. The OTTR system 

generates daily reports concerning ATC status, 

intent and actions and delivers these both to 

the FAA to support TBFM development and 

to NASA to support NextGen research. NASA 

initially invested in OTTR to support departure 

scheduling analyses for the Precision Departure 

Release Capability (PDRC) research activity; 

however, OTTR data are available for use by all 

NASA NextGen researchers. 

Learn more about the Airspace Systems Program at: www.aeronautics.nasa.gov/programs_asp.htm 

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