Achieving a Higher Capacity National Airspace System:
An Analysis of the Virtual Airspace Modeling and
Simulation Project
Megan Smirti and Mark Hansen
WORKING PAPER
UCB- ITS- WP- 2009- 1
February 2009
ISSN 0192 4141
Publications in the working paper series are issued for discusion and
are not considered final reports. Comments are invited.
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Achieving a Higher Capacity National Airspace System: An Analysis of the
Virtual Airspace Modeling and Simulation Project
Megan Smirti1*, Mark Hansen2
1PhD Candidate in Civil and Environmental Engineering
University of California, Berkeley, National Center of Excellence for Aviation Operations Research,
109 McLaughlin Hall, Berkeley, CA 94720- 1720, USA
E- mail address: msmirti@ berkeley. edu
* Corresponding Author
Telephone: 415- 816- 0925
Fax: 510- 642- 5687
2Professor of Civil and Environmental Engineering
University of California, Berkeley, National Center of Excellence for Aviation Operations Research,
114 McLaughlin Hall, Berkeley, CA 94720- 1720, USA
E- mail address: mhansen@ ce. berkeley. edu
Abstract
The Virtual Airspace Modeling and Simulation ( VAMS) project developed by the National Aeronautics and Space
Administration ( NASA) presents a detailed plan for increasing National Airspace System capacity. Interviews with
aviation experts regarding the VAMS project led to lessons learned which can inform current modernization plans
and processes, as the current system prepares for modernization. According to experts consulted, development
should include a small number of project developers who provide periodic opportunities for wide stakeholder
feedback; roadmaps should incorporate uncertainly and provide project guidance on a high level; and simulation
tools are valuable to modernization efforts, yet assumptions should be documented and their sensitivity understood.
Keywords: Aviation System Modernization, Stakeholder Involvement
1. Introduction The Virtual Airspace Modeling and Simulation ( VAMS) project was a recently concluded effort to pinpoint and
merge technologies and strategies to increase the capacity of the National Airspace System ( NAS). It is believed by
both domestic and European airspace authorities that current airport and airspace capacities are not enough to
accommodate the demands of the future, and that capacity increases must be on a grand scale to handle this demand
increase ( Joint Planning and Development Office, 2006; Ky and Miaillier, 2006). Beginning in fiscal year 2002, the
VAMS Project sought to provide the foundations required to define and assess a next generation air transportation
system. The project supports National Aeronautics and Space Administration ( NASA) strategic efforts to “ enable a
safer, more secure, efficient, and environmentally friendly air transportation system” ( National Aeronautics and
Space Administration, 2006).
The VAMS project was an innovative systems level effort to increase NAS capacity. It was one of few projects
which did not solely develop individual component technology, but rather developed independent capacity
enhancing concepts and then integrated them into a single concept. The project furthermore developed a plan for the
research, development, and deployment of the concepts and created an assessment tool that can be used for a wide
range of future concepts. NASA had many roles on the VAMS project, as they were a facilitator, a funding agency,
and a concept developer. Five domestic aviation companies and NASA centers developed concepts to increase
capacity independently, and then came together to further refine and blend the concepts, which led to an overall
System Wide Concept ( SWC). Next, a roadmap was developed based on the current federally- funded aviation
projects through 2015. The SWC was then assessed with a non- real time assessment tool. Throughout the process,
input was gathered through discussions and technical exchange involving NASA and the chosen developers.
NASA’s effort, although not explicitly intended to be, was a precursor to the current federal initiative to
modernize the NAS termed the Next Generation Air Transportation System ( NextGen). This Joint Planning and
Development Office ( JPDO) effort has a larger scope than VAMS, in the number of stakeholders involved, in the
domains covered, and in the magnitude of the targeted capacity increase. Therefore, the lessons learned from
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VAMS will provide valuable insight into the development of NextGen, as well as other modernization efforts. To
capture opinions and lessons learned, the authors spoke with multiple national and international authorities to gather
their feedback regarding the VAMS development process and final product. This paper synthesizes the feedback
from key aviation experts and comments on current aviation modernization efforts with regard to the insights
collected.
To fully understand how VAMS can inform current modernization efforts, a review of the two modernizations
underway is presented here. Currently, there are two efforts being undertaken to modernize the airspace system.
These two efforts include the United States’ initiative, NextGen, and the European initiative termed Single European
Sky Air Traffic Management Research Program ( SESAR). Both are large scale modernization initiatives with
similar goals: both seek to transform the current air transportation system for their respective regions to meet the
growing demand for air transportation ( Joint Planning and Development Office, 2006; European Organization for
the Safety of Air Navigation, 2006). SESAR is also looking to eliminate the fragmented approach to Air Traffic
Management ( ATM) in Europe ( European Organization for the Safety of Air Navigation, 2006).
After determining that existing capacity must be increased to keep pace with the growing demand for air travel,
the United States government, through VISION 100 legislation, mandated the multi- government agency JPDO and
created the modernization initiative NextGen. The overarching vision was for a system that addresses critical safety
and economic needs in civil aviation, such as increased capacity, while fully integrating environmental impact,
national defense, and homeland security improvements in a cost effective manner ( Joint Planning and Development
Office, 2006). The JPDO is responsible for creating and implementing an integrated plan for NextGen and for
leading the research required to support this plan ( Dillingham, 2006). The JPDO itself is comprised of personnel
from different government agencies with aviation- related missions, and incorporates working groups which include
both private and public aviation experts. The JPDO also collaborates with private and public agencies that are
working on NextGen capabilities ( Dillingham, 2006).
SESAR, led by European Organization for the Safety of Air Navigation ( EUROCONTROL) began in 2005 with
a similar realization that air traffic in Europe is growing at a rapid rate, and the system will not keep pace with
demand given the current capacity levels. SESAR is an in- depth reform of ATM, both technologically and
institutionally. SESAR is being developed in two main phases, the definition phase and the implementation phase.
The definition phase incorporates the development of the ATM master plan, which includes definition of
performance targets and development of operational concepts and a roadmap for their implementation. The
implementation phase will complete the development and deployment pieces which make up implementation. One
stated key of SESAR is governance; there are over 600 participants involved in SESAR development, according to
one respondent involved with the effort ( Ky and Miaillier, 2006).
The following section will begin with a discussion of the research questions and methodology. A literature
review on project development, planning and assessment follows. Next, a description of the VAMS project
including the expert reactions and feedback to the project are presented. The paper concludes with statements and
suggestions for current modernization development.
2. Research Questions
The motivation behind this research is to answer three key questions related to system wide modernization.
1. How should one develop system wide modernization concepts?
2. How should the modernization of a legacy system proceed?
3. How can one effectively evaluate and assess a particular system wide concept?
Through these questions, this research can inform current and future modernization efforts.
This research takes a unique approach by presenting a fully formed solution in the form of the VAMS
project. The VAMS project will act as the completed project from which these research questions can be answered
through expert feedback. This study therefore will use a ‘ learning by doing’ approach. To focus this research on the
VAMS project, certain targeted research questions related to the VAMS project will be addressed.
The following are the high level categories of the VAMS questions.
1. VAMS Development of System Wide Modernization Concepts
• Is blending the way to combine multiple disparate capacity enhancing concepts?
• Is the VAMS SWC acceptable?
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2. Preparing Roadmaps for Modernization of the Legacy System
• What role do top- down and bottom- up project plans play in planning for VAMS?
• What types of roadmaps are needed to effectively plan for VAMS?
3. VAMS Evaluation of the System Wide Concepts Through the Use of Large Scale Models
These more targeted research questions related to VAMS will assist in answering the overarching research
questions.
3. Methodology
To gain insight into the VAMS development process methodology and outcomes, the details of the project were
presented to 12 individual recognized authorities. Some respondents spoke to the authors alone, while others
included additional members of their organization due to different expertise. Each respondent or respondent group
received a briefing on the details of VAMS. At different points during this presentation, the respondents were asked
for feedback through specific and open- ended questions. Being exploratory questions, participant responses varied
from direct answers to the questions to direct answers along with digressions to related topics they wanted to share.
Participants were selected because of their expertise and experience with aviation modernization efforts and
aviation policy. They were also selected because they represent experts who would respond based on an evaluation
of project and not necessarily the official position of their organization. The authors conducted interviews for this
study from February through July 2007. Experts represented a wide variety of aviation organizations, including:
• Aeronautics Development
• Aviation Service Provider
• Consultant/ Researcher
• Airport Authority
• Air Carrier
Their opinion and insight on VAMS and modernization processes are now discussed with the goal of informing
modernization processes. The following section presents a literature review, followed by the details of the VAMS
project and expert reaction and feedback.
4. Literature Review
VAMS was motivated by the ambitious goal of making major improvements to a large- scale, complex, safety-critical,
and mature socio- technical system. Bringing change to such systems is difficult. Engineers, planners,
policy analysts, and social scientists have investigated the challenges and means of overcoming them. Below we
summarize key themes from this work that are most relevant to the VAMS endeavor, and which provide a
framework for evaluating the development and planning of a system wide modernization efforts.
As the solutions proposed by a transformation project require acceptance from many stakeholders, a review of
consensus building literature will prove helpful. Regarding consensus building, Innes ( 2004) notes eight conditions
which need to hold for consensus building, or collaborative problem solving, to be successful. Of the eight, two are
particularly relevant to this study: 1. the inclusion of a full range of stakeholders; and 2. a practice that begins with a
mutual understanding of interest and avoids bargaining based on stakeholder position. Each aviation stakeholder
group must be represented, and these groups must believe fully in the rationale for modernization. Each stakeholder
group must also hold an important reason to participate in a collaborative effort, and therefore a common
understanding of need must be present. Participating in such a collaboration effort is often seen as a drain by
organizations, as each must expend valuable resources on the effort. Therefore, each organization must expect to
benefit from participation, mainly because each groups’ interests are not being served well by performing the tasks
individually ( Dillingham, 2006).
Related to aviation modernization efforts, a transition model was developed for large scale NAS modernization
( Mozdzanowska et al., 2007). This transition model defines key points that lead to a transformation of the air
transportation system. After a period of demand growth and behavior shifts, stakeholders enter into a period of
awareness building, where each stakeholder forms its own mental model of the situation. What follows is a change
process in which stakeholders evaluate the projections for the future, and influence one another through change
discussions. This change process involves a negotiation loop because many stakeholders hold their own set of
preferences and issues of importance, and because stakeholders are affected differently by potential changes to the
system. The transition model involves two feedback loops, or iterative processes, which allow for negotiation
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regarding the details of the solution in question and also a loop that allows for refinement of project details taking
external factors into account. This type of planning model represents iterative planning, allowing for constant
refinement of a solution until full stakeholder buy- in has been achieved. The idea that modernization efforts should
be planned in this manner is also discussed by The Boeing Company, who noted that an operational concept should
first be developed iteratively, with objectives, requirements, and the operational concept continually cycling until a
final concept is reached ( Sipe, 2005).
With regard to the transition model, it is noted that a successful transition hinges on a clear definition of the costs
and benefits for each stakeholder ( Mozdzanowska et al., 2007). This is an effective way of clearly understanding
the agenda and position of each stakeholder, and also guides deliberations about project financing. Understanding
and measuring costs and benefits is also an effective way for providing stakeholder incentives should a negotiation
stall; this is important due to the potential for project time to increase rapidly if there is an inability to overcome
strong stakeholder opposition. Developing true costs and benefits figures, however, is a challenge. There is much
literature on the difficulty of understanding the true forecasts of costs and benefits. Basing plans on forecasts has a
high level of uncertainty built in, as they tend to be highly flawed ( Flyvbjerg et al., 2002).
The VAMS modernization effort is based around achievement of an end goal, and then the development of
policies and concepts as the means to achieve this goal. This method of project and policy development is
particularly challenging for complex projects, as discussed by Lindblom ( 1959), who states that in practice policies
are formed through experiences rather than by defining a goal and the means to achieve that goal. Lindblom ( 1959)
notes two policy making paths: 1. defining the end states and the means to achieve it ( termed the root, or top- down
method), and 2. determining policies through comparing a limited set without fully determining ends or means
( branch, or bottom- up method). For transportation policy making, Garrison and Levinson ( 2005) note that a factor
of the branch method, learning from direct experience, is a key factor of policy making; they develop an experiential
policy model which incorporates experience and feedback from existing transportation policies, as these existing
policies continually inform new policy development.
5. VAMS Project and Findings
The VAMS project had three objectives: ( 1) Define and evaluate system level air transportation operational
concepts that extend to the year 2025; ( 2) generate enabling technology roadmaps for selected concepts; and ( 3)
establish a set of capabilities such as performance measures, and tools for assessing these concepts ( National
Aeronautics and Space Administration, 2004). This section will describe these three objectives, which became the
three main steps of the project. Expert feedback, including an incorporation of the categories of feedback, on key
components of these objectives will also be discussed.
5.1 Overview of Stakeholder Feedback
A comprehensive analysis of the respondent input leads to four clear categories of responses. These
characterizations and their explanations will assist in understanding the perspective of the respondents and also
provide context of their feedback. These categories are the Pluralists, Economists, Incrementalists, and
Traditionalists.
5.1.1 Pluralists
The pluralists are those respondents who were concerned primarily with the incorporation of stakeholder
feedback in a system wide modernization effort. Regarding VAMS, their responses were focused around the need
and importance of a diversity of developers and stakeholders. Pluralists also agreed roadmaps are a key part of
development, and were glad to see the VAMS project included a project plan. However, pluralists warned against
developing detailed roadmaps, and believed that planning should allow for multiple iterations of stakeholder
feedback.
The following are some sentiments from respondents in this category.
“ It was easier for NASA to defer stakeholder involvement until the end because you can’t really get
consensus if there are too many stakeholders from the beginning. Having the stakeholder involvement
( in the beginning) would be good too, but it would also add cost.”
“ I think more people ( developers) might have picked up more concerns, but it also depends on what’s
the expected output of this process. What they ( NASA) expect is something they can take out to the
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broader community…( therefore) I would urge NASA to have a process to include everyone with every
perspective.”
5.1.2 Economists
The economists1 pressed for VAMS development decisions to be grounded in economic theory, as well as the
incorporation of economic instruments to manage capacity. They advocated for a cost and benefit analysis of the
concepts before research, development, and implementation were planned. The economists also wanted economic
constraints on capacity, such as auctions and pricing, evaluated along with the other capacity enhancing technologies
proposed. The economists were encouraged by NASA’s effort to incorporate policy into VAMS.
The following are some sentiments from respondents in this category.
Regarding simulation tools, “ any tool trying to bring us toward the future has got to look at some of
these other very large factors, like economic forces, like public policy forces.”
“ It would be nice to see some data to start this off on – what are the problem sets and what’s the value
of solving these problem sets, what are the problems today and what are they tomorrow.”
“ I think this is a very nice and worthwhile thing ( NASA) did, the independent concepts and blending…
( But) in the end, we have to remain more conscious about what’s going on economically. I believe the
most economically efficient ( capacity allocation method) is through auction, to determine who’s going
to use the resources. Economically, it’s far more efficient than what’s going on today.”
5.1.3 Incrementalists
The incrementalists were concerned that planning for the VAMS project was top down, and did not incorporate
the local needs and perspectives of individual airports and communities. These respondents felt that capacity
enhancement is achieved through local efforts and small changes within these localities. Respondents in this
category wanted to see more feedback loops involved in the VAMS development and planning process to allow for
input and incremental changes. They also wanted to see more realism injected into the project, as these respondents
do not consider large changes in policy and infrastructure to be realizable.
The following are some statements from those who are characterized as incrementalists.
“ Why model five additional runways when it will only be one in reality?”
“ You have a goal, and ( the roadmap is) trying to get the end state. But the roadmap is missing a little,
because it put goals out there, but there has got to be more thought and detail to the middle process…
There has to be a reason why ( the roadmap schedules implementation) 12 yrs ( away). It is like a
business planning process, where do you want to be five years from now, what is it going to be, what
does it take to get there, so at the end, they make sense.”
“ One of the ideas is that for every ( item) that is necessary to realize that improvement, analyze where
we are in the lifecycle so far, what the expected duration of the lifecycle phase is, up to deployment and
identify what the earliest possible date of deployment could be for that particular item. If you know that
for the various ( items), then you can at least say something about the earliest date you might be able to
realize the operational improvement.
This is typically a bottom up approach, because the performance driven perspective is the other way
around. One says ‘ we need from the target setting this level of capacity by that year, then we say this
and that solution will deliver it by that year, which means that this and that ( item) needs to be
operational by this year,’ and then you start calculating backwards. But both need to come together at
some point.”
5.1.4 Traditionalists
The traditionalists were focused on achieving capacity enhancement through infrastructure expansion and policy
changes. These respondents wanted to see a change in policies which are constraining capacity and also wanted to
1 Economists that fall into this category are not necessarily economists by trade, but rather their feedback is focused
on economic theory.
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see new capacity built in the form of runways and supporting infrastructure. Traditionalists further believe that there
should be less focus on technology for capacity enhancement.
Respondents in this category responded to technology advancements with the following policy comments.
“ We need to understand the fundamental need for capacity increases through building more runways.”
“ The FAA ( Federal Aviation Administration) has to ( change) the mandatory spacing. You can’t get close to the
person ( aircraft) in front of you - jet blast and wake turbulence. Also, you have two sets of eyes watching the
same airplane, crashes won’t happen. Make the spacing 2 miles. It’s safe. We can do closer spacing between
airplanes. It’s the rules, and someone needs to have the guts to say we need to change the rules, and for the last
20 years, no one is able to do that… We just work as close as we can with the rules, but there’s a need to
change some rules.”
All respondents shared both aspects of VAMS they felt should be emulated and also provided constructive
criticism of aspects of the project. Figure 1 provides a summary of all expert responses to the three objectives of the
VAMS project. Full Support indicates that one respondent fully supported the VAMS methodology used to achieve
that objective; Limited Support means the respondent agreed with the methodology at a high level and provided
constructive criticism of certain aspects of the methodology; No Support indicates the respondent did not agree with
the methodology on a high level.
5.2 Step One: Development of the System Wide Concept
The first step of the VAMS project was the identification and development of specific capacity- enhancing
concepts, and the blending of the best attributes of these concepts into an integrated SWC. This process occurred in
two phases: the first phase involved NASA’s solicitation of independent concepts from industry and academia; the
second phase was the blending of these concepts together into a unified plan, or SWC, for the NAS. The SWC is
envisioned as an integrated set of revolutionary technology concepts which will increase the capacity of the NAS.
While many specific capacity- enhancing concepts have been developed by NASA and other organizations, they had
not yet been brought together and blended into a coherent vision for large scale NAS modernization. The following
discusses some details of the two phases.
5.2.1 Phase One: Individual Concept Development
5.2.1.1 Overview
The first phase of the SWC development focused on the identification and development of specific capacity-enhancing
concepts. Independent concepts were solicited from NASA, industry, and academia through the use of a
NASA Research Announcement process. Once concept proposals were selected, organizations developed their
concepts independently, with periodic discussions amongst developers and NASA. As stated in the internal NASA
VAMS Concept Blending Plan dated March 31, 2005, the organizations worked autonomously, and were provided
with a functional model which fully encompassed government views of the “ desired functionality of a future
system- wide NAS concept” to act as a framework for development. The result of this solicitation process was eight
concepts from five independent developers which collectively covered gate- to- gate operations of the NAS domains
– Surface, Terminal, En Route, and National ( Table 1). Other organizations were chosen as developers, however
their concepts were either integrated into one of those developed by another organization or eliminated.
5.2.1.2 Participant Feedback
The experts had a great deal of feedback on the independent concept development. The number of stakeholders
to involve in concept development is, as also suggested from the literature, a difficult decision. Respondents noted
benefits of a small group of stakeholders, and that “ a small group is able to accomplish a great deal in a short
amount of time.” It was also noted that a small group has the ability to produce very detailed concepts. In a small
group, developers must still agree on a conclusion, but a small group can reach an agreement more quickly, and in
more detail, than a large group. However, as noted in the literature discussed in Section 4, there are benefits from
including a full range of stakeholders. One pluralist, while noting the ability of a small group to achieve a detailed
concept, also noted “ the ability of a small group to achieve buy in is almost zero… it is very difficult to get
stakeholders to buy in to a concept they did not develop.” While more developers and stakeholders lead to a less
detailed concept, there exists a higher likelihood of concept acceptance. The pluralists also noted the issue of cost
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involved with more stakeholders: NASA paid organizations to participate in VAMS, and it would have been cost
prohibitive to do so for a larger set of stakeholders
Regarding this stakeholder inclusion issue, many respondents were concerned that the developers included were
too similar: multiple NASA centers and multiple aviation system integrators. Incrementalists and Pluralists noted
that a larger diversity of concepts could have been generated with more developers. More developers and increased
developer diversity was considered desirable because one could develop a larger technology set. “ The idea of
blending is good, but you can’t blend with such a limited set of technology. You have to blend a very broad set of
technology” noted one pluralist. Concept diversity was viewed as a valuable contribution to the effort – an
incrementalist respondent group noted they would like to see a diversity of concepts, and then a rank ordering of
those diverse concepts, followed by a concept selection process.
Following up on concept diversity, respondents expressed frustration that VAMS did not employ airlines,
airports, controllers, and pilots. One incrementalist noted “ Controllers and pilots became one of my biggest assets in
developing solutions for my airport ( because) they get very creative in finding solutions.” Furthermore, it would be
exceptionally difficult to gain ex post buy in from these particular stakeholders. However, a traditionalist expert
group disagreed, citing potential conflicts of viewpoint in clashes in stakeholder interest that would have slowed
down, or even undermined, the process of attaining a consensus SWC. As VAMS was looking to document
concepts, and did not wish to have these concepts go undocumented due to stakeholder disagreement, a full range of
inclusion was not possible according to a respondent involved in the VAMS project; however, if VAMS was
looking further to implement these concepts, the experts noted that opposition would be ahead.
All four respondent categories noted that inclusion of a full range of stakeholders could also include international
stakeholders. One respondent noted, “ I would even not limit ( developers) to US companies, I would go world wide
to get new concepts.” While governmental restrictions can exclude international developers, international
stakeholders have the ability to both provide information on initiatives abroad, and also ensure compatibility
between domestic and international aeronautics systems. Respondents from airlines and aeronautics development
were especially concerned that concepts developed without international input would not be developed with
worldwide interoperability of their aircraft in mind. One respondent noted the difficulty in equipage if each ATM
system needs separate equipment: “ If an air traffic controller in US needs one kinds of box, and Europe has other
kinds of requirements, and another one in Asia, there’s not that much room in the aircraft to put different boxes. The
boxes add weight, and take up space. What airlines do is to minimize the different kind of things they need to put on
the aircraft because each one is costly.”
Finally, regarding the actual concepts themselves, it was noted that while concept development is a key step
towards system wide modernization, it should not be the exclusive focus. A pluralist respondent group noted that
few of the concepts that are being entertained today by modernization processes are “ new” concepts, but rather
similar to ideas from past projects that have yet to reach fruition. Pluralist and incrementalists argued that concept
refinement and project planning to establish a roadmap that has both political support and stakeholder buy in is the
most important modernization challenge. One respondent noted that “ the US should not invent JPDO III; they need
to settle down and let people actually work.” This respondent further noted that concept development should have a
definitive end – at a point, it is crucial to end concept development and allow the concepts to become the vision.
This will provide stakeholders with time to become familiar with the idea, a key stage of the transition model
( Mozdzanowska et al., 2007). As defining the vision was included in the VAMS process, respondents applauded
this step ( Table 2).
5.2.2 Phase Two: Blending Process
5.2.2.1 Overview
Phase Two involved concept “ blending,” where teams of developers formulated the synthesized concept by
combining and choosing the best attributes of the independent concepts. The concepts were mapped to the
functional model noted in Section 5.2.1.1, to functionally decompose each concept. Any gaps that the concepts
presented, or overlaps between the concepts, were addressed by drawing on existing projects or modifying an aspect
of one or more concepts.
The result of this blending process was the SWC, a synthesized version of the individual concepts that addresses
all NAS domains and promises a major gain in system capacity. From the SWC, features, which are capabilities that
fully comprise the goals and plans of the SWC, and enablers, which provide the infrastructure and interconnections
between functions for a complete gate- to- gate concept, were developed. As the features and enablers technically
define the VAMS SWC, one can envision the VAMS SWC as the set of established features and enablers.
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5.2.2.2 Participant Feedback
Many respondents applauded the methodology of gathering independent concepts and blending the best
attributes of these concepts ( Table 3). Respondents across all categories were impressed by the thoughtfulness of
the blending methodology; a process which did not simply group concepts but rather take many strong concepts and
combine them into a synthesized idea. One pluralist noted “ blending concepts is the most cost effective and
efficient way to finalize a concept… it leverages ideas and concepts that have been tested and deemed important by
industry or government.”
Some of those consulted, however, noted many alternative methods of concept development and blending.
Respondents were concerned over the difficulty of “ start( ing) from a collage and put( ting) these concepts together”
and that therefore there “ needs to be an organization that develops concepts and generates a set of requirements for
the implementation of the concepts” which would supersede the need for blending. Economists also felt that costs
and benefits to meet these requirements should have been produced before the concepts. One economist noted “ it
would be nice to see some data to start this off on. What are the problem sets and what’s the value of solving these
problem sets, what are the problems today and what are they tomorrow… ( We need to measure) the magnitude of
problems.” A full understanding of the costs and benefits would help prioritize the needs of a modernization effort,
which would assist in understanding interdependencies in concepts and insure the most beneficial concept sets were
implemented first.
Respondents felt that developing concepts, leading the blending and bringing together developers was a highly
appropriate role for NASA. They agreed “ NASA should bring people to the table” to be innovators of technology
through research. Respondents felt this was a major step forward for NASA, noting “ VAMS and ACES are
wonderful work, ( they have) economic, policy, ( and) system complexity.” However, many respondents across all
categories were concerned that the VAMS product was very technology- focused, and that by having a technically
focused research group perform this research other solutions were not given priority. It was recommended that
another organization more focused on policy should be involved in the development so the policy issues could be
fully addressed, and also that more time be spent on changing current aviation policies.
5.3 Step Two: Roadmap Development
5.3.1 Overview
A research, development and implementation schedule for the VAMS features and enablers from 2006 to 2025
was developed in this step. To build the transition strategy to the VAMS SWC, an assessment of the relationship
between the goals of the FAA’s Operational Evolution Plan ( OEP) v5.0, which defines all funded aviation projects
until 2015 at the 35 major airports, and the SWC concept was performed ( NASA, 2006). This allowed the
scheduling of VAMS research, development, and implementation of the features and enablers to best leverage OEP
planned projects. Given this mapping and the schedules for the OEP and the VAMS SWC, it was then possible to
determine the impacts of OEP and the VAMS SWC on one another. An actual roadmap for VAMS could then be
developed with milestone dates to plan for the research and development and the implementation of the features and
enablers.
5.3.2 Participant Feedback
This planning process used the goal of VAMS, which is to increase capacity levels by 2025, as the end state, and
then looked backwards from that date to plan development. Incrementalists noted that the most effective planning
method given funding and political constraints is to develop both a top- down and bottom- up road map. The bottom-up
road map involves determining the current concepts which are already in development, and noting in which stage
of the development lifecycle they are. The top- down roadmap involves starting with development targets, and
planning backwards from these development targets. Than it can be determined how these plans work together and
the realism in the top down roadmap.
Regarding the VAMS method of roadmap development, members of all respondent categories were pleased to
see an effort to define a goal and mission to reach the end state, but noted that the roadmap did not fully address the
means of accomplishment. The incorporation of OEP plans was considered by most interviewees to be an important
step in the direction of a bottom- up roadmap; as OEP ends in 2015, however, most respondents felt that this fell
short of what was needed to fully articulate a bottom- up roadmap. One noted that basing the roadmap on “ OEP is
giving too much credit to the OEP. The OEP is … a way to raise awareness to the program and way to organize the
initiatives. OEP is a focusing mechanism.” A roadmap focused on requirements and the current state of research
was suggested by the incrementalists, for a more bottom- up perspective.
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Another benefit of performing both top- down and bottom- up roadmaps is to decrease the uncertainty involved in
planning for unknown technology developments. A top- down roadmap can help establish goals, while the bottom-up
roadmap can determine the current state and then realistically plan the timeline to the end goal. If these timelines
do not match up, priorities can be reordered, or the scope of the project changed. For this reason, many
incrementalists and pluralists noted that exact dates in a roadmap, like those used in the VAMS roadmap, should not
be included, but rather defined vaguely. Because dates are uncertain, they act like placeholders to rank order
technology development and also set approximate targets for political and funding reasons. Respondents noted that
this is also an effective way to capture the uncertainty due visualizing and understanding technology advances,
because there is a great deal of uncertainty in what technology will be available in the future.
To effectively plan for uncertainty, incrementalists and pluralists suggested having development horizons ( short
term, medium, and long term) and activities which depend on one another in a plan, rather than mapping functions
by specific date. Planning horizons would handle the issue of planning for the diversity of the system VAMS is
working to modernize. This is important, as the economists pointed out, because implementation of many SWC
elements depend on initiatives by local actors, such as airports. Each airport has its own unique needs, and therefore
airports will need different concepts at different timelines. Furthermore, other plans must be determined to take the
network nodes into consideration. Many economists expressed concern over the lack of an infrastructure roadmap,
as airports would need expanded ground facilities to handle an increase in operations.
Beyond planning for technology, there is a great deal of uncertainty that comes into play when planning for
institutional changes. Many respondents were concerned that NASA’s focus on technology kept them from
incorporating important factors into their roadmaps as “ historically NASA is … heavily weighted towards
technology and not enough on operations, economics, public policy, and the environment.” Although VAMS had a
stated ATM focus, there were some features, such as increased use of regional airports, and also enablers, such as
performance- based services, that involve institutional changes and concerned economists and incrementalists.
Incrementalists noted that these features and enablers require changes in deeply embedded policies that cannot be
placed on a roadmap with a date, but instead must incorporate the uncertainty that comes with policymaking. To
best plan for the uncertainty, a feedback loop that incorporates a chance for stakeholder reaction to the policy, and
then policy refinement in response to stakeholder reaction, was suggested by many respondents. This iterative
planning cycle was advocated by many incrementalists and pluralists, who noted that the more stakeholders are
involved in this feedback loop, the stronger the prospects for success.
Because of the amount of institutional changes and policy making needed by VAMS, respondents from all
stakeholder groups felt the roadmap development for concepts was out of touch with how policy and system changes
are made. While goals and plans are important at a high level, they felt a more realistic roadmap should be
developed, to show the incremental approach most effective in policy planning. This would be a more detailed map,
noting the steps and feedback loops which would take place during research, development, and implementation. In
general, traditionalists and incrementalists felt this would help focus on how the VAMS project can transition from
the current state of the NAS to the VAMS goal. These respondents surmised that NASA may not feel like this is
their work, and suggested NASA along with FAA should perform this kind of study. Respondents lastly expressed
that planning for this type of wide scale modernization is difficult, and were concerned that planning processes
focused on top down project plans are the norm. A feedback summary can be seen in Table 4.
5.4 Step Three: Preliminary Assessment of VAMS SWC
5.4.1 Overview
The third objective of VAMS was to develop a set of analytical and computational models and methods to
conduct detailed and system- level assessments of the SWC. The core of this step was the development of the
Airspace Concept Evaluation System ( ACES) modeling and simulation tool. ACES is a non- real- time modeling and
simulation environment that enables a comprehensive assessment of the impact of the SWC. To use ACES to assess
the SWC, each concept was independently assessed ( either by ACES or another tool). Thorough this assessment,
the capacity enhancing ability of the concept was determined. This capacity enhancing ability could be an increased
sector capacity, decreased queuing delays on the surface, or an increased airport throughput capacity. Then these
capacity increases were applied toward the year that the roadmap states that the concept in question will be
implemented ( NASA, 2006).
To determine the impact of the SWC, ACES was used to model gate arrival delay in 2025 based on varying
levels of traffic growth. Using demand forecasting tools, unconstrained and constrained traffic demand sets were
developed to reflect the goal of doubling of system throughput. Next, airport demand to capacity ratios were
calculated to determine if an airport was operating at or below 70%. If the ratio was above this threshold, a
10
feedback loop in the assessment process would utilize two VAMS features and allocate new closely spaced runways
and increase the use of regional airports. The new runways are enabled by the Very Closely Spaced Parallel
Runways ( VCSPR) feature, which increases capacity through the use of paired operations for arrivals and departures
in both instrument meteorological conditions ( IMC) and visual meteorological conditions ( VMC). The diversion of
flights to regional airports is from the Increased Utilization of Regional Airports ( IURA) feature of VAMS, which
leverages enhanced ATM at regional airports to handle traffic from nearby congested hubs ( NASA, 2006).
The resulting average gate arrival delays were then calculated by ACES to be less than 10 minutes. The VAMS
SWC achieved its target increase in effective capacity of an additional 100% throughput at equal or reduced delay
levels compared to the base year. The SWC assessments confirmed that no single feature of the SWC could in and
of itself satisfy the throughput goal.
5.4.2 Participant Feedback
Respondents in all categories agreed that an integrated modeling tool can be effective and powerful in assessing
the capacity enhancing benefit of concepts, and noted that ACES is “ a perfect tool to use.” However, many
respondents felt that just using the ACES assessment was limiting and that other assessments would be equally
important. Economists were concerned that the assessment process did not include a cost benefit analysis. This is a
noted “ Next Step” in the VAMS documentation, however, economists noted that this is a crucial component of the
entire development process. A cost benefit analysis should be done in the concept development phase, the planning
phase, and the assessment phase, so the project insures each step makes sense to implement.
Traditionalists applauded VAMS for identifying the basic critical need for capacity, in the form of new runways
built at certain airports. One traditionalist applauded a study that does “ not just look at capacity expansion through
technology” and that capacity must be increased on the ground. However, many respondents in other categories
addressed the concern over issues new runways bring that were not addressed in the study. The first is that new
runways bring enhanced traffic, and therefore the need for infrastructure. Next, inclement weather days continue to
choke capacity, and respondents questioned the ability of all features to fully enable use of runways during IMC.
Respondents were skeptical of ability of the concepts to close the capacity gap between IMC and VMC, and
expressed concern that an increase in just VMC capacity could encourage airlines to increase their flight schedules
leading to further delays and cancellations in IMC.
Many respondents were also concerned with the reliance on regional airports for capacity increases. Many
regional airports do not have the ground crew or the transportation connection to desirable locations to act as
reliever airports. Furthermore, many respondents noted these areas would be served more if there was more of a
market, and economists in particular were concerned that this concept was encroaching on the business model of
airlines. One traditionalist noted that “ there are commercial reasons why we have hubs. The whole point of air travel
is to get somewhere quickly, and if I land, and I have to drive two hours to get to where I need to be, I’m not going
to do it unless there is no other option. The reason why ( the New York metropolitan area airports) are so busy is
because ( there are) flights that go directly to a lot of cities, non- stop, and that saves people time and energy.” The
inter- modal aspect of the problem should be studied; furthermore, incrementalists noted some regional airports
would work well, whereas some of them may not work at all. Respondents in all categories noted they would like to
see a preliminary plan regarding the use of regional airports.
New runways and use of regional airports had many respondents calling for a focus on policy instead. Despite
the promise of closely spaced runways, the environmental process and issues surrounding noise would not allow for
the development of all those runways. All respondent categories pointed to current initiatives to close airports due
to environmental and noise constraints, and incrementalists noted the extremely long lead times necessary to build
runways. One traditionalist noted that capacity gains can come in the form of new policy, especially regarding
minimum spacing rules and requirements. “ We can do closer spacing between airplanes. It’s the rules, and someone
needs to have the guts to say we need to change the rules, and for the last 20 years, no one is able to do that… We
just work as close as we can with the rules, but there need to be some change in the rules.” This traditionalist feels it
is political will that is barring some capacity increases.
Because of the additional runways needed, many experts felt that NASA had not met their burden of proof that
VAMS is capable of handing a 100% increase in throughput. Experts noted that the number of additional runways
and regional airports should have been limited in the modeling and simulation, because that would bring the process
closer to realism due to political difficulty. A feedback summary is provided in Table 5.
11
6. Conclusions & Looking Ahead
Respondents were very interested in the future of VAMS and what could be learned from the VAMS effort.
Respondents also were interested in seeing research on how to improve system wide modernization efforts. In the
light of these comments, this section draws lessons for current modernization efforts based on the feedback of the
respondents. Based on discussions and literature regarding these modernization efforts, it seems that both NextGen
and SESAR are recognizing some of these lessons and while not adequately considering others.
6.1 Concept Development and Stakeholder Involvement
Both NextGen and SESAR involve a collection of concepts that have or will have been fully vetted by numerous
stakeholders. The NextGen documentation was developed by numerous working groups from a large number of
organizations. Other stakeholders, as well as the general public, participated by providing comments on the Concept
of Operations ( Federal Aviation Administration, 2007). According to NASA researchers, the JPDO has not
excluded anyone or any group that is interested in participating in the development of NextGen. According to
SESAR researchers, SESAR was developed by drawing on concepts from the member states, to insure that both
these state’s interests were met and also that strong concepts were leveraged. SESAR and NextGen share
information through a Memorandum of Cooperation, which allows for the international interaction which was noted
as a factor which could help the project by expert groups ( Ky and Miaillier, 2006).
SESAR and NextGen incorporate independent concepts from multiple developers, a point that was discussed as
being overall beneficial to a project. A blending process for these concepts however has not been explicitly
performed. Both modernization efforts involve high level of stakeholder involvement, which, while slowing the
projects down, will most likely contribute to more stakeholder buy- in.
The question of the level of stakeholders to involve in a project does not have a definite answer. However, there
are conclusions that can be drawn from an analysis of the VAMS project. Allowing stakeholders a voice during
each step of the development process is seen as important by the pluralists and the incrementalists. Either after or
during each step of the a project, the ability for public comment or comment by key stakeholder groups who would
be effected by the proposed changes would allow for stakeholders to voice their concerns, and also to feel that they
had a hand in development, which was noted by the pluralists as a key to stakeholder acceptance. However, because
having a large number of stakeholders slows a project, developing detailed concepts in a timely fashion may require
keeping the number of developers fairly small but having an iterative, and intensive, stakeholder comment process.
6.2 Planning
VAMS was primarily a top- down planning endeavor, developing an end- state system that would attain certain
specified capacity and performance goals in a future year. Planning theorists such as Lindblom ( 1959) distinguish
this approach from a bottom- up, or incrementalist, approach. VAMS also incorporated bottom- up elements such as
creating a roadmap based upon the OEP. Most respondents agreed that NAS modernization requires a combination
of top- down and bottom- up planning. There was also strong, though not unanimous support, for an approach that,
like VAMS, first develops an end- state solution and then performs bottom- up planning to assess “ how to get there”.
A concern with this approach was that it does not assure sufficient progress in the nearer term to prevent major
imbalances between demand and capacity.
SESAR has a project plan that is focused on the relationship between development steps rather than dates ( Ky
and Miaillier, 2006). In their plans, both NextGen and SESAR separate the near-, mid-, and long- term objectives
and targets, which is important for setting priorities while a project is in development. NextGen is still focused on
an end- state system as the goal is to satisfy an increase in throughput of 200% current traffic levels ( Joint Planning
and Development Office, 2006). Project planning success will partially depend on how the bottom- up and top- down
roadmaps are mapped as discussed by the pluralists. Regarding iterative planning, the NextGen and SESAR
development cycles allow for a great deal of stakeholder feedback and refinement of ideas ( SESAR Consortium,
2007; Government Accountability Office, 2007). While this can allow for all stakeholders to agree on a concept and
move forward, it also interferes with the ability to fully refine an idea and allow stakeholders to become familiar
( Mozdzanowska et al., 2007). NextGen is also participating in iterative planning processes for their technical
processes, which involves modeling concepts and their impact, and incorporating this into plans ( Government
Accountability Office, 2007).
A conclusion regarding detailed project planning is that it might best be carried out by an organization outside of
the concept developers. Because planning is dependent on policy and funding issues, it may best be performed by
an agency that has the political power to carry out, or fund, the steps in the planning process. What could be
performed effectively by the concept development group is a high level project plan which is that is not focused on
12
dates but rather a sequence for development. This can assist the funding agency in prioritizing investments and
development decisions as they create the detailed project plan.
6.3 Assessment
NextGen and SESAR both present their own modeling strengths and weaknesses. A tool to model and simulate
the whole of SESAR does not yet exist according to discussions with project researchers. A modeling and
simulation tool is considered important going forward, supported by the general respondent agreement. NextGen is
able to leverage the ACES resource, and therefore assess concepts both independently and as a system wide concept
( NASA, 2007). On the cost analysis side, SESAR has quantified the costs and benefits of the concepts early on in
the development process to be able to understand the contributions of the concepts. NextGen has reported difficulty
in developing detailed cost estimates for individual NextGen concepts ( Government Accountability Office, 2007).
Some key lessons from this study is that both a system wide modeling tool and comprehensive cost estimates are
needed to understand the impacts of individual concepts and a project as a whole. These research findings also
recommended a sensitivity analysis on the assumptions made during an assessment process, something for both
projects to take into consideration in their future use of assessment tools.
This study illustrates the challenges in identifying capacity enhancing concepts, planning for the research,
development, and implementation of these concepts, and assessing the impact of these concepts. This study also
recognizes the importance of incorporating sound planning methodologies into system wide modernization efforts.
By discussing the VAMS project with a number senior members of the aviation community, this study has identified
points of consensus on how modernization should proceed, as well as areas of disagreement requiring further
reflection, discussion, and debate.
7. Acknowledgments
The authors would like to thank NASA, and Harry Swenson in particular, for their support of this research. A
great deal of information was provided by those experts who were interviewed for this study, and the authors thank
them for their time and support. The authors would also like to thank University of California, Berkeley Civil and
Environmental Engineering Student Jue Wang for the support she provided collecting and synthesizing interview
responses.
8. References
Dillingham, G. L., 2006. Air Traffic Control: Status of the Current Modernization Program and Planning for the
Next Generation System. Testimony Before the Subcommittee on Transportation, Treasury, the Judiciary, Housing
and Urban Development, and Related Agencies, Committee on Appropriations, U. S. Senate, Thursday, May 4,
2006. Available at: http:// www. gao. gov/ new. items/ d06738t. pdf. Accessed June 27, 2007.
Eurocontrol, 2006. SESAR: Objectives and Scope.
Available at: http:// www. eurocontrol. int/ sesar/ public/ standard_ page/ overview. html. Accessed August 12, 2007.
Federal Aviation Administration, 2007. Capacity Needs of the National Airspace System: 2007- 2025 ( FACT 2).
Available at: www. faa. gov/ airports_ airtraffic/ airports/ resources/ publications/ reports/ media/ fact_ 2. pdf. Accessed
July 29, 2007.
Flyvbjerg, B., et al., 2002. Underestimating costs in public works projects: Error or lie? Journal of the American
Planning Association. 68( 3), Summer, 279- 295.
Garrison, W., and Levinson, D., 2005. The Transportation Experience: Policy, Planning, and Deployment. New
York: Oxford University Press, Chaps. 2- 3.
Government Accountability Office, 2007. Next Generation Air Transportation System: Progress and Challenges in
Planning and Implementing the Transformation of National Airspace System. GAO- 07- 649T, March 22, 2007.
Available at: http:// www. gao. gov/ htext/ d07649t. html. Accessed on July 29, 2007.
Innes, J. E., 2004. Consensus building: Clarification for the critics. Planning Theory 3; 5.
13
Joint Planning and Development Office, 2006. Concept of Operations for the Next Generation Air Transportation
System. Version 0.2, July 24.
Ky, P., and Miaillier, B., 2006. SESAR: Towards the new generation of air traffic management systems in Europe.
ATCA Journal of Air Traffic Control, January- March.
Lindblom, C. E., 1959. The Science of ‘ Muddling Through’. Public Administration Review, 19( 2), Spring, 79- 88.
Mozdzanowska, A., et al., 2007. The Dynamics of Air Transportation System Transition. In Proceedings of the
2007 Air Traffic Management Conference. Barcelona, Spain.
NASA, 2006. Virtual Airspace Modeling and Simulation System- Wide Concept Report Volume 2 Technical.
VAMS Project Office, NASA Ames Research Center.
NASA, 2007. NASA & The Next Generation Air Transportation System ( NEXTGEN): The Current National
Airspace System. Available at: http:// www. aeronautics. nasa. gov/ docs/ nextgen_ whitepaper_ 06_ 26_ 07. pdf.
Accessed July 29, 2007.
SESAR Consortium, 2007. SESAR D2 Feedback Report. Available at:
http:// www. sesar- consortium. aero/ mediasandfiles/ File/ 05_ docs/ SESAR_ D2% 20Feedback% 20Report_ final. pdf.
Accessed September 15, 2007.
Sipe, A. L., et al., 2005. Capacity enhancing air traffic management concept. Journal of Aircraft, 42( 1).
14
Independent
Concept
Concept
Developer
Independent Concept Highlights
Advanced Airspace
Concept ( AAC)
NASA Ames
Research Center
 Automation of separation monitoring and control
 Assurance for ground and cockpit through technology
 Automated Trajectory Server
System Wide
Optimizations
( SWO)
NASA Ames
Research Center
 Optimal Routes For Aircrafts From Origin To Destination
 Neighboring optimal Wind Routing ( NOWR)
 Enhancing Flight Plan ( FP) and deconflicting conflicts
Point- To- Point Air
Transportation
System ( PTP)
Sensis Corp.  Enhances major airports Air Traffic Management
 High degrees of automation
 Expands ground operations
 Advance en route ATM automation
Surface Operation
Automation Research
( SOAR)
Optimal
Synthesis, Inc.
 Surface Traffic Management ( GoSAFE)
 Flight- Deck Automation ( FARGO)
 Integrated operation of automation
Metron Weather,
Technologies
Enabling All- weather
Maximum Capacity
by 2020 ( MW)
Metron Aviation,
Inc.
 Coupled weather and traffic prediction
 Flexible traffic management around weather constraints
 Shared situational awareness, coordination, and information
distribution
Metron Surface,
Automated Airport
Surface Traffic
Control ( MS)
Metron Aviation,
Inc.
 Automated surface traffic control
 Terminal area- wide planning
 Improved NAS integration
Terminal Area
Capacity Enhancing
Concept ( TACEC)
Raytheon Co.  Address the primary terminal capacity constraints
 Flight path boundaries free of any wake vortex hazard
Wake Vortex
Avoidance Concept
( WVAS)
NASA Langley
Research Center
 Sensor data fusion, terminal weather, and wake prediction
 Dynamic wake- safe reduced spacing for single runway arrivals
Table 1. Independent Concepts.
15
Table 2. Summary of Concept Development Feedback.
Table 3. Summary of Concept Blending Feedback.
Category Feedback Summary Representative Quote
Pluralists • A small group of developers can
achieve a great detail of detail quickly
• A small group is unable to achieve
their goals because stakeholders who
were excluded from the development
process will not buy- in to the idea
“ The ability of a small group to achieve buy in is
almost zero… it is very difficult to get
stakeholders to buy in to a concept they did not
develop.”
Economists • Hidden, unmentioned constraints
such as funding concerns did not allow
development to occur on a broad scale
“ I think having more developers is better than
having fewer. But from what you described, the
developers, I don’t think they looked as broad as
they could have.”
Incrementalists • Inclusion of a full range of
developers will allow for concept
definition and refinement based on
varied individual perspectives
“ Controllers and pilots became one of my biggest
assets in developing solutions for my airport
because they get very creative in finding
solutions.”
Traditionalists • Inclusion of international developers
could have leveraged already existing
research going on abroad
“ There are concepts Europe is developing now
that are far ahead of US development.”
Category Feedback Summary Representative Quote
Pluralists • Blending is an effective way to
ensure all stakeholder ideas are
incorporated into an integrated
solution
“ Blending concepts is the most cost effective
and efficient way to finalize a concept… it
leverages ideas and concepts that have been
tested and deemed important by industry or
government.”
Economists • Blending is one of many methods to
come to a conclusion regarding
capacity enhancing concepts
“ I think it’s ( blending is) reasonable. Some
methodology builds up as I read the document. I
think there’s inability to capture capacity. I think
very nice and worthwhile thing they ( NASA)
did, the independent concepts and blending. In
the end … we have to remain more conscious
about what’s going on economically.”
Incrementalists • Blending is effective; however more
steps in blending were needed. The
concepts should be ordered based on
a certain criteria, and blending based
on this criteria.
“ If someone is going to do a follow up with the
program, I would… pull together all resources
and go through all that’s available. And then
rank order and blend them at the end.”
Traditionalists
• Blending, or however concepts are
agreed upon, is secondary next to
securing approval for the concepts
themselves
“ We all know it takes… years to approve
anything. That’s the biggest hurdle that you have
to overcome is how do you take the ideas or
concepts, develop the infrastructures required
and rapidly deploy the stuff... There have been
lots of great ideas that never made it because by
the time they approve the technology, it was so
old that it’s not worth putting it in place. “
16
Table 4. Summary of Road Map Development Feedback.
Category Feedback Summary Representative Quote
Pluralists • Number of stakeholders involved in
land use changes is very large
Runway expansion “ is not going to
happen… with the environmental constraints.”
Economists • Concepts involve business decisions
of airlines and airports
“ The airlines have to have the people and the
equipment at the regional airports and today,
they don’t find it financially successful to do
it.”
Incrementalists • It is impossible to put date goals on
concepts without pinpointing a
funding source for these concepts
“ NASA came up with great ideas, but they
partially missed the physical details and
constraints… these are local decisions”
Traditionalists • Runway expansion is a necessary
reality which VAMS incorporates
into the model well
“ We need to understand the fundamental need
for capacity increases through building more
runways.”
Table 5. Summary of Assessment Process Feedback.
Category Feedback Summary Representative Quote
Pluralists • The concepts involve implicit policy
decisions which cannot be planned
out on a roadmap with specific dates
“ How do you schedule the time it takes to get
Congress to agree on a new policy?”
Economists • Date goals cannot be planned with
certainty for business decisions
In regard to planning “ the whole economic
aspects have got to be considered in the user
equipage. There’s not business case for it. The
faster people equip, the faster we will be able to
implement.”
Incrementalists • Certain airports will need changes
and enhancements out of order with
the roadmap; the roadmap should be
less focused on dates and more on the
order of need for improvements
“ Airport master plans should be considered.
OEP is only 35 airports, which is kind of
limiting things. The problem with OEP is you
are assuming technology, assume something and
may not be there, so should need a backup
plan… The roadmap is missing a little, because
it put goals out there, but there has got to be
more thought and detail to the middle process.”
Traditionalists
• It is impossible to put date goals on
concepts without pinpointing a
funding source for these concepts
“ There has to be a cost and funding source.
Because in these days, you can’t just have an
idea and concept hanging out there on their own,
they have to be tied to different projects and
programs or they will never get funded.”
17
0
1
2
3
4
5
6
7
8
9
10
Define Operational
Concepts
Generate Technology
Roadmaps
Modeling and Simulation
Number of Respondents
Figure 1. VAMS Feedback Histogram.
Figure 1 Legend
Full Support
Limited Support
No Support