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NASA Advisory Council Aeronautics Committee Meeting

November 15, 2018

Langley Research Center

Hampton, VA

Welcome

Mr. John Borghese, committee chairman, called the meeting to order and welcomed 

everyone. He asked everyone present in the room to introduce themselves with name 

and affiliation. Dr. Jaiwon Shin, NASA associate administrator for aeronautics, added 

his welcome and then briefed the committee on the appointment and confirmation of 

NASA’s news Administrator, Jim Bridenstine, as well as other political appointees 

including Jim Mohard as deputy administrator and Jeff DeWit as chief financial officer.

Mr. Borghese reminded the committee about the difference between recommendations 

and deliberations. Recommendations are a course of action being proposed by the NAC 

for NASA’s consideration. It must be actionable and requires a written response from 

NASA. A finding is something about which the NAC wishes to state an opinion. It 

doesn’t require a response from NASA.

Mr. George Finelli, Langley Research Center’s aeronautics research director, provided 

the committee with an update on the many ways in which Langley supports the 

research portfolio of NASA’s Aeronautics Research Mission Directorate (ARMD). He 

noted Langley’s recent centennial anniversary and provided some examples of the 

center’s heritage contributions to both aviation and space.

Dr. Greg Hyslop asked Mr. Finelli how data gathered from the Low Boom Flight 

Demonstration mission, which is managed in part at Langley, would be shared and help 

open a new industry of commercial supersonic air travel. Mr. Finelli responded that the 

priority is to meet NASA’s critical commitment of delivering a database that will help 

regulators change rules regarding noise from sonic booms. Dr. Shin offered that the 

actual X-59 aircraft design may not directly lead to a commercially-viable design and

noted there are other challenges that must be overcome and cited; as an example 

landing and takeoff noise of supersonic airplanes. Jay Dryer (NASA ARMD’s deputy 

associate administrator for programs) noted that experience in developing and using 

design tools for the X-59 was shared with industry and will inform the continuing 

evolution of those tools for designing future aircraft.

Dr. Karen Thole asked for help in understanding NASA’s strategy for sharing 

information with the international community while at the same time ensuring the U.S. 

industry remains competitive, particularly as it relates to the community response data 

from the X-59 flights. Mr. Dryer explained that the rule changes to come from the 

database will be set by the International Civil Aviation Organization; but the technology 

in designing, building, and flying the X-59 is very much a U.S. asset intended to benefit 

U.S. industry.
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eVTOL Noise Modeling and Technology Solutions

Ms. Susan Gorton, NASA’s manager for the Revolutionary Vertical Lift Technology 

(RVLT) project, presented to the committee an overview of the project, its primary 

strategy being to enable a broad expansion of vertical lift applications. More specifically,

the project is working to improve current configuration cost, speed, payload, safety, and 

noise; open new markets with new configurations and capability; and capitalize on the 

convergence of technology in electronic propulsion, autonomy, and flight controls.

Ms. Gorton noted that NASA’s technology emphasis has deliberately shifted toward the 

lighter end of the spectrum in terms of mass, market, mission, range, overall 

configuration and propulsion concepts. The configurations range from one passenger to 

15-passenger vehicles, each with different types of wings and propulsion systems.

Research areas being considered for each configuration include propulsion efficiency, 

performance, rotor-rotor interactions, rotor-wing interactions, structure and 

aeroelasticity, aircraft design, operational effectiveness, safety and airworthiness, and 

noise and annoyance. The last two areas are receiving primary focus within the RVTL 

project.

Discussion

Mr. Borghese asked how safety and certification issues would influence coming up with 

various configurations. Ms. Gorton gave some examples of how this happens and noted 

some of the tradeoffs that must be considered, such as reliability versus mass or giving 

up payload for extending range.

Mr. Anil Nanduri, following up on the previous question, asked if there was any 

reference data from NASA’s own tradeoff deliberations that could be used as a 

benchmark for industry to consider as they work to develop their own standard models. 

Ms. Gorton replied she wished she could say yes, adding it was NASA’s goal to be able 

to support such a sharing of data.

Several committee members contributed to a more detailed discussion concerning 

safety and reliability as it relates to the various types of power architectures being 

considered not only for the four NASA concept study vehicles, but by industry in 

general, and what that power architecture includes. Ms. Gorton noted that, for now, 

NASA’s idea of what propulsion architecture includes is from the drive train to the 

propulsion system.

Dr. Mike Francis asked if any work is being done to look into acoustic aerodynamic 

interaction, where the acoustical energy could be potentially damaging to the aircraft’s 

structure. Ms. Gorton replied yes, NASA is starting to look at that as their research tools 

allow. NASA also is looking at how vibration is transmitted through structure, with high 

cabin noise and reverberation being key concerns.
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Committee members also offered comments about safety and reliability as it relates to 

vehicle size, focusing on tradeoffs between redundancy and reliability, and to what 

extent NASA is looking into these issues as the vehicles become smaller and the 

emphasis may be more on operations. Dr. Shin noted these questions are being 

considered within the various aeronautics projects and answers shared and integrated 

so everyone can benefit from them.

Committee members discussed the issue of when does noise become an annoyance, 

noting that public perception of noise can widely vary, not only from a measurable 

decibel level standpoint, but from intangible considerations as well. Measuring public 

perception of noise remains a challenge.

Dr. Hyslop suggested that NASA’s artwork in depicting rotor and Urban Air Mobility 

(UAM) activity should not overly emphasize the presence of pilots or human 

passengers, as unmanned cargo vehicles will be just as active. 

Dr. Thole advised that engaging K through 12 students and making sure they 

understand what noise is, and how it is produced, could aid in public acceptance of 

UAM activity. Dr. Allison added that connecting work on public perception of noise – the 

annoyance factor – to psychological research or human factors research would also be 

helpful.

Mr. Borghese noted there was a focus on noise and safety and expressed his concern 

that the focus was more on noise than safety. Dr. Allison agreed. Committee members 

suggested opportunities where safety could play a larger role as systems are refined or 

new systems developed. The example of the rotors, from the actuator assembly down 

into the power train, was given.

Findings/Recommendations

The Committee applauds the Rotary Vertical Lift Technology (RLVT) project

initiative with a focus on the two most critical areas needed for acceptance of Urban

Air Mobility (UAM): noise and safety. The Committee offers the following

suggestions. The ability to accurately model noise generation and its mitigation is

particularly important in the design development of rotors for wide range of

operations. There is a significant amount of work being performed around the world

including OEMs on noise modeling and design for low noise. NASA could leverage

this effort. A particular area in which NASA could add differential value is in

understanding and assessing public acceptance and perception of noise generated

by air vehicles that will be used in UAM. For example, what is the most annoying

part of the noise when there are many rotorcraft flying simultaneously in the vicinity.

This topic could present an opportunity to engage K-12 students possibly as part of

a NASA grand challenge.

Safety of vehicles in UAM is of critical importance and NASA could play a significant
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role in this area. The Committee suggests performing a Failure Mode Effects and

Criticality Analysis (FMECA) including probabilities by component on several

reference vehicle architectures. One project could be the analysis of the propulsion

system starting with a tiltrotor and including the complete powertrain with and

without cross winds. Determining the safety level that not only ensures safety but

also meets the public’s perception on what is required on safety would benefit the

industry. The development of a model that allows analysis of various parameters

like safety and noise would allow designers to test innovative designs of air vehicles

for UAM.

Subsonic Technology Development Strategy

Richard Wahls, NASA’s strategic technical advisor in the Advanced Air Vehicles 

Program (AAVP), presented an update on the agency’s subsonic technology 

development strategy, with at least some emphasis on how AAVP ties to Urban Air 

Mobility (UAM) research.

He began with a global overview of aviation and how fixed wing aircraft will fit into the 

mix of different types of aircraft flying at different altitudes and speeds, and with different 

missions. That “fit” will remain the most significant part of aviation as the global 

backbone of air transportation into the foreseeable future. A number of current statistics 

regarding air travel were presented to underscore that importance.

Dr. Wahls continued his overview of the global market and its challenges to U.S. 

leadership in aviation by noting that intense and expanding international competition for 

manufacturing aircraft is growing. While Boeing and Airbus continue to form alliances 

with other companies, such as Bombardier or Emery Air, new alliances between Russia 

and China could mount a serious challenge to eroding the U.S. market share of building 

aircraft.

Another key challenge from the global marketplace that is guiding NASA’s research 

investment decisions is societal demands for more environmentally friendly aircraft. 

New regulations requiring airlines to report carbon output are about to go into effect, 

adding to the list of environmental concerns the aviation community must continue 

working to address. The best way to do this is to find ways of getting new and more 

advanced aircraft into the market faster and at lower cost.

Dr. Wahls said that all four of NASA’s aeronautics programs are addressing these goals 

in some manner. A specific technology he offered as an example of research toward 

these goals was advanced composites. He also called out the work being done to take 

emerging technologies outside the aviation community, and to find ways to take 

advantage of them in solving these challenges.

Dr. Wahls reviewed some of the goals NASA has set in the past for near-, mid-, and 

long-term goals for subsonic aircraft dealing with several variables, including fuel burn, 

emissions, and noise. He then described some of the technologies and aircraft 
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configurations that were proposed as a result of the research driven by those goals. The 

research led to possible solutions that covered a wide range of ideas, from new aircraft 

shapes enabled by the use of composites to the use of additive manufacturing (3D 

printing) and electric propulsion.

Dr. Wahls shared a video that displayed some of the technologies NASA is working on, 

particularly in the area of electric propulsion. A discussion followed about hybrid-electric 

and all-electric propulsion, when each might be feasible for widespread use, and what 

are some of the technical and safety-related problems with the use of batteries, heat 

transfer, and heat rejection.

Discussion

Dr. Allison asked about applying research in advanced composites to the UAM market. 

Mr. Wahls noted the imminent conclusion of the current advanced composites project 

and described some ways in which results of that effort can be applied not only to the 

aviation market, but also to other areas. Dr. Allison noted the increasing use of 

composites in the automotive market and that some of that work, especially with tooling, 

might be helpful in the aerospace community. Several panel members discussed some 

of the manufacturing challenges aircraft manufacturers face in the introduction of 

widespread use of advanced composites.

A similar discussion followed a little later, also led by Dr. Allison, regarding the potential 

lessons-learned NASA might gain from studying or collaborating with the automotive 

industry in the use of batteries and managing an electric propulsion system, while also 

recognizing there are significant differences between the way the two industries would 

use such systems. Mr. Jon Montgomery from NASA noted the agency made a 

conscious decision not to pursue battery development, mostly leaving it to the battery 

and automotive industries to continue to invest their research dollars. Dr. Allison noted 

there is a gap in developing a tool for examining the integration of different battery 

concepts into an innovative automotive or aircraft system. He suggested NASA might 

have the expertise and incentive to address that gap and develop such a tool.

Dr. Francis cited some recent papers describing the potential negative effects on 

aviation due to the impact of climate change on atmospheric conditions. At their worst, 

those effects could lead to significant clear air turbulence that would make passenger 

comfort during flight difficult to achieve, if not completely unviable. He urged NASA to 

consider this potentiality in making decisions about future research goals. Mr. Wahls 

noted that NASA has not considered ride quality as a metric to study in the design of 

future aircraft, the emphasis being more on passenger safety.

Dr. Thole asked about the use of universities in solving some of these challenges 

related to batteries and electric propulsion. Dr. John Cavolowsky of NASA provided a 

brief update on the agency’s University Leadership Initiative project and noted there is 

indeed a role for the academic community to conduct research in this area.
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Findings/Recommendations

The Committee recognizes that there are thermal management opportunities where 

NASA can contribute as one of the biggest new challenges in designing all-electric or 

hybrid-electric aircraft is heating and cooling of the electric powertrain components. The 

Committee suggests NASA consider the innovation that currently exists in the 

automotive industry in terms of tools. There is a gap in tools and this an opportunity for 

innovation that NASA could fill. The Committee believes that this might be a good area 

for collaboration with universities and industry. Another important area is battery 

cell/pack architecture and how it connects to vehicle-level high voltage architecture to 

meet aviation standards. Additionally, all-electric aircraft will require innovative design 

work to make battery packs that are lightweight with adequate thermal management. 

Other methods for electric energy storage, including fuel cell technology, for example, 

should also be considered. Universities could be of help in the development of needed 

tools and models and the rapid testing of their fidelity through measurements on 

additive manufactured parts. Issues that could shape the future of subsonic flight, such 

as predicted climate change-induced atmospheric behavior should also be examined.

Autonomy Update

Jay Dryer, NASA aeronautics’ deputy associate administrator for programs, presented 

an update on the topic of autonomy. He prefaced his talk by underscoring that while 

other areas of NASA’s aviation research can trace its heritage going years and years 

back, the research area of autonomy is still very new.

Mr. Dryer reviewed that assured autonomy is one of NASA aeronautics’ six strategic 

research thrusts. One reason is because autonomy is seen as enabling capability for 

moving forward with safe technology that will transform aviation and open a new era of 

air transportation at every level of operations. He noted that many of the finer details of 

NASA’s role in this area are still being identified. Much will depend on finding the best 

balance between what NASA can do and what the rest of the autonomy community is 

doing and where they need help.

Mr. Dryer explained that work on autonomy is not being done for autonomy’s sake, but 

because it will help in concert with other technologies to enable future innovations 

related to Urban Air Mobility (UAM), for example. In fact, NASA’s work on UAM is 

helping to focus its research activities with autonomy. Achieving public acceptance and 

trust is important as well.

Mr. Dryer said another emphasis of research in autonomous systems is related to air 

traffic management (ATM). An important part of that is to identify the requirements for 

developing an ATM system that is resistant to disruption, capable of dynamically scaling 

to safely meet demand and complexity, and be inclusive of new entrants and

use cases flying in the National Airspace System.
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Discussion

Dr. Allison suggested NASA consider a different approach to autonomy by identifying

specific, incremental goals related to UAM operations and then build the rest of an 

architecture around that. Mr. Dryer noted that NASA’s approach to UAM is more from a 

big picture standpoint in which autonomy is just one part. Dr. Allison said he wasn’t sure 

he completely agreed with that approach and offered some examples of how NASA 

might do things differently. Mr. Dryer said this is the kind of input NASA needs right now 

as it continues to identify what would be most beneficial to the community.

Mr. Nanduri suggested an approach to identifying the definition of different levels of 

autonomy, which could help standardize terminology and expectations about what is 

achievable at each level. For example, in a six-level scheme, level 6 might be a 

completely humanless operating vehicle and system. By introducing fully-understood 

levels of autonomy, specific research goals could then be identified and worked toward.

Dr. Allison proposed an approach in which different road maps to autonomy could be 

developed that are based on an incremental approach, perhaps beginning with the 

automotive industry and expanding in complexity and more autonomous operations 

from there. 

Several panel members addressed a potential future in which more and more aircraft 

rely on fewer and fewer pilots, to the point of reaching Mr. Nanduri’s level six of a 

humanless vehicle. Such a future remains distant, but short-term problems such as a 

shortage of pilots could force an increasing reliance on increasingly more sophisticated 

autonomous systems and quicken such an outcome. Public acceptance of a humanless system could be helped by a step-by-step increase in reliance on safe and secure 

autonomous systems. Dr. Hyslop suggested an autonomous aid could be introduced 

into the cockpit – he used R2-D2, the droid from Star Wars, as an example – to build 

public acceptance and confidence.

Mr. Borghese commented that NASA could help through its research and experience by 

generating data the FAA will need for coming up with requirements for safely certifying 

autonomous systems for use. Mr. Dryer commented that is a major emphasis of NASA’s 

work on autonomy.

Dr. Thole reiterated her concerns that not enough students are following career paths 

that would be helpful in developing fully autonomous systems for aviation. They are 

being lured away by the giants of Silicon Valley, who are considered to be more 

innovative and quicker to react to industry needs. She offered some potential solutions 

that could help turn the tide, and others offered ideas related to workforce development, 

STEM engagement, and university partnerships as well.
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Findings/Recommendations

Autonomous aircraft and related airspace operations and management enable 

emerging aviation capabilities in areas where the United States needs to maintain 

global leadership. The Committee offers the following suggestions:

 NASA can assume a fundamental role as the conduit between industry and the 

FAA for certification requirements and the verification and validation approach.

 Engage FAA early because autonomy is a disruptive concept to the standard 

DO-178C software certification process.

 Develop cyber security requirements which are not being addressed sufficiently 

by industry and are needed for safe operation.

The Committee expressed concern about the flow of talent from aerospace and 

universities to the broader tech industry. Engineers with autonomy and artificial 

intelligence backgrounds need to be enticed to enter and remain in the aerospace 

arena. The excitement generated by emerging Urban Air Mobility where NASA is 

working is an area that generates interest to attract and retain these engineers in 

aerospace.

Air Traffic Management Exploration (ATM-X)

Akbar Sultan, NASA’s director of the Airspace Operations and Safety Program, 

presented an update on ATM-X, short for Air Traffic Management – eXploration. After 

describing ATM-X’s place within NASA aeronautics’ program structure, he emphasized 

a key point that NASA’s investment in this area of air traffic management, which serves 

the Unmanned Aircraft Systems (UAS) community, does not mean the agency is 

abandoning traditional users of the National Airspace System (NAS). One of ATM-X’s 

primary objectives is to examine the concept of a service-oriented architecture, which 

could be used by traditional and emerging users alike.

Mr. Sultan reviewed the project history and noted how early goals evolved as a greater 

understanding was gained about the scope of UAM operations. ATM-X’s overall project 

goal is to enable safe, efficient airspace access for all users, vehicles, and missions by 

creating new airspace management concepts and technologies which leverage UAS 

Traffic Management (UTM) principles. This architecture must be scalable, flexible, and 

resilient to uncertainties, degradation and disruptions. Through collaboration, it must 

provide seamless access to the airspace for all users and those providing third-party air 

transportation management services.

Mr. Sultan described a wide range of research activities and results related to ATM-X 

work during the recent past. The presentation inspired a number of questions from the 

committee, which led to further discussion and observations covering a variety of 

operational scenarios.
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Discussion

Mr. Sultan was asked to define more clearly exactly what is a user service-oriented 

architecture. He said that it’s a collaborative increased use of third-party traffic 

management services that enables efficient use of the airspace by users for their own 

purposes. This is a more flexible approach to traffic management than the traditional 

approach in which a single, government-managed system directs users through the 

airspace in very specific ways based on traffic density, weather, and other variables.

Mr. Drennan asked if the Grand Challenge will be used as a “sandbox” to demonstrate 

and better understand some of the operational challenges associated with this. 

Mr. Borghese noted that roughly 70 percent of delays in the NAS are due to weather 

issues and that there is no project related to improving weather predictability. Improved 

forecasting and 4D modeling of weather could greatly increase the amount of traffic the 

NAS could handle. He asked if other projects are addressing the weather problem, or if

the assumption is that current capabilities will be relied upon. Mr. Sultan said the project 

doesn’t have that kind of expertise and noted that other organizations – such as NOAA 

– are working on improving available weather products which could improve traffic 

management capabilities, whether the users are traditional airlines or users from the 

UAM community.

Dr. Allison asked Mr. Sultan to elaborate further on the definition of a service-oriented 

architecture, asking if the elements of this architecture and its operation are of the same 

general idea as those being developed for UTM. Mr. Sultan said it was, adding they 

envision a very federated system operated by many interconnected providers, instead 

of the current monolithic system. There was a discussion on the operational details and 

potential challenges of such a system. It was noted that managing/resolving overlaps or 

conflicts among service providers and/or users will benefit from the work being done by 

the Integrated Demand Management (IDM) project. Mr. Sultan then elaborated on the 

current status of the IDM concept.

Findings/Recommendations

The Committee applauds NASA in exploring the future of air traffic management 

needed to be viable for the significant increase in air travel in both conventional routes, 

new air mobility solutions, and unmanned air vehicles. The Committee recommends 

exploring the potential of federated systems operated by third party service 

organizations. The NASA Grand Challenge is an opportunity to test some of these ATMX approaches. Transition from the existing, very safe air traffic management system to 

potential future ATM-X concepts needs to be examined as well. The Committee 

suggests that the design of the system take into account seamless integration into the 

current system. The Integrated Demand Management (IDM) project has shown 

promising results to the FAA and industry allowing a path to transition. IDM is the type 

of NASA research that is not well known outside of the aerospace sector but offers 

benefits to the current air traffic management system and the flying public.
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List of Attendees

Committee Members

Dr. Eric Allison

Mr. John Borghese

Mr. Scott Drennan

Dr. Mike Francis

Dr. Greg Hyslop

Mr. Anil Nanduri

Dr. Tom Shih

Dr. Karen Thole

NASA

Dr. John Cavolowsky

Mr. George Finelli

Ms. Susan Gorton

Mr. Jim Heideman

Mr. Jon Montgomery

Mr. Steve Reznick

Ms. Irma Rodriguez

Dr. Jaiwon Shin

Mr. Akbar Sultan

Dr. Ed Waggoner

Mr. Rich Wahls

FedWriters (Meeting support)

Ms. Abigail Casas

Mr. Steve Spearman

Mr. Eric Stone