Securing the Future of U.S. Air Transportation: A System in Peril (2003)

Given below is a complete list of the committee’s findings, recommendations, and the big question, in the order in which they appear in the report. The bulleted items in recommendations containing lists of research areas are either listed alphabetically or grouped topically. The committee did not prioritize research areas in the lists.

Recommendation 1-1. Goals. The future vision for the air transportation system should be supported by research and technology goals leading to improved performance. Measurable long-term targets supported by sound analyses should be established to assess progress toward the goals. Research should support the establishment of quantifiable goals in areas where progress is difficult to measure.

Finding 1-1. Challenge of Increased Demand. The continued success of aviation and the benefits that it provides will require changes to accommodate increased demand. This is the most critical long-term issue facing all aspects of the air transportation system. Issues associated with safety and security, capacity, environmental compatibility, and consumer satisfaction are all exacerbated by greater demand, and the effectiveness of near-term solutions in each of these areas will be diminished by long-term growth in demand for air transportation in the United States.

Finding 1-2. Going Beyond Business as Usual. Business as usual, in the form of continued, evolutionary improvements to existing technologies, aircraft, air traffic control systems, and operational concepts, is unlikely to meet the needs for air transportation that will emerge over the next 25 to 50 years. The likely result would be an air transportation system where growth in demand has been greatly curtailed by undercapacity in the air traffic management system; the environmental effects of aviation; customer dissatisfaction with available levels of comfort, convenience, and cost; and/ or factors related to safety and security.

The Big Question. How can change within the air transportation system be accelerated quickly enough and directed with enough agility to avoid problems and achieve future goals while managing (1) the influence of increased demand and other external pressures and (2) conflicts between different goals and stakeholders? How can the system be prevented from changing too slowly, drifting, or going in the wrong direction?

Finding 1-3. Context for Future Requirements. Valid research requirements for the air transportation system depend on understanding how the U.S. air transportation system of the future will fit into both the national (intermodal) and international air transportation systems.

Recommendation 1-2. National Vision. The process of improving the long-term performance of the air transportation system—and organizing a corresponding long-term research and technology program—should start with a unified, widely endorsed, national vision that specifies goals in each key area of interest to the commercial aviation community. The vision should establish goals related to safety and security, the capacity of the air transportation system, environmental compatibility (noise and emissions), the satisfaction of consumer needs, and industrial competitiveness. It should include a clear set of guiding principles and a strategy for overcoming transitional issues.

Recommendation 1-3. Leadership. No single organization has the responsibility and authority for developing a comprehensive solution to the challenges faced by the U.S. air transportation system. Strong, focused leadership is needed. Federal leadership should be exercised by an agency or office with (1) the responsibility, authority, and financial resources necessary for defining air transportation system architectures through a centralized planning function, (2) an understanding of the interactions among system performance parameters, demand, and economic factors, such as the methods used to fund federal activities in support of the air trans-

portation system, and (3) the credibility and objectivity to garner the active support of other air transportation stakeholders in government, industry, and the general public. This requires, among other things, a leadership group composed of individuals with a broad aviation perspective and a willingness to accept the risks of (1) looking ahead and (2) allowing others to help define the future.

Finding 2-1. The Challenge. Developing meaningful and useful operational concepts stemming from a broadly defined vision of the air transportation system 25 to 50 years hence is a critically important task in the process of improving the performance of the system.

Recommendation 2-1. Operational Concepts 2050. The federal government, working with other stakeholders in the air transportation system, should develop a coherent set of operational concepts to support a vision for the air transportation system in 2050 to guide (1) long-term research and (2) the evolution of and transition to a more advanced air traffic management system. The set of operational concepts should be continually, objectively, and rigorously evaluated (for example, through comprehensive simulation and modeling) and iterated to reflect feedback from stakeholders, conflicts between alternative concepts, and the best understanding of the future costs, benefits, and requirements that are likely to evolve in response to changes in the real world, the current state of technology and systems operations, and future expectations. Strong national leadership should coordinate the efforts of all involved federal agencies and other stakeholders in the air transportation system to build toward concepts that best support the vision.

Recommendation 2-2. Enabling Technologies. Enabling technologies applicable to a wide range of operational concepts should be developed in parallel with development and evaluation of long-term operational concepts so that the necessary technologies will be ready for whichever operational concept proves to be most beneficial. Technology areas of particular interest include the following:¹

• Automation technologies applicable to fully automated systems; automated decision aids; and information systems for communication, visualization, situation assessment, and the prediction of future conditions.

• Technologies that support distributed, collaborative decision making and that foster coordination and interactions among multiple human and automated elements of the system.

• Methods and technologies for moderating and abating the impact of noise and emissions locally, regionally, and globally.

• Methods and technologies for predicting or directly sensing the magnitude, duration, and location of wake vortices and the potential to reduce separation standards without compromising safety.

• Methods for identifying (1) the information required for situation awareness when humans are assigned novel (untried) tasks in future operational concepts and (2) sensor, computing, and display technologies for better supporting situation awareness, judgment, decision making, and planning. Relevant technologies include synthetic vision, cockpit and controller displays for novel air traffic management functions, fast-time simulation and computational functions for predicting future conditions, and alerting. These methods and technologies should be investigated for their potential to (1) reduce separation standards without compromising safety and (2) enable changes in the roles of humans within the system.

• Systems-engineering methods that are (1) capable of conceiving and analyzing systems of the complexity of air transportation and (2) suitable for governing the design, testing, and implementation of these systems.

• Avionics technologies that will provide ubiquitous and transparent communication, navigation, and surveillance capabilities; enable cost-effective, reliable air traffic management; and contribute to the reduction of separation standards without compromising safety.

Recommendation 2-3. Design of Complex Human-Integrated Systems. The design of human-integrated systems—that is, systems that rely on the combined activities of humans and machines—presents significant challenges at every level, from the systems level (e.g. creating effective teamwork within operations involving many human operators and automated system elements) to the detailed design level (e.g., developing operating procedures and system displays). Research in the following areas is required to understand and address these challenges:

• A broad, interdisciplinary approach that includes technology designers, users, and experts in human and organizational performance from the earliest stages of conceptual design through final implementation to develop technology that effectively supports human behavior and recognizes the need for concurrent design of procedures, training, and technology.

• Geographically distributed activities, such as coordinated decision making and planning, that are mediated by computers and automated system elements.

• Human factors, human-automation interactions, and functioning of teams of humans and automated system elements.

• Specific impact of newly automated functions and changes in human roles.

• System engineering methods for addressing organizational and systemwide issues.

Finding 2-2. Nontechnological Impediments to Success. Technological research alone is insufficient to achieve the future vision. Research is also needed to (1) better understand the economic, environmental, political, institutional, and managerial factors involved in achieving key goals, (2) take advantage of synergies among these factors, and (3) overcome related impediments.

Recommendation 2-4. Research Needs Beyond Technology Development. The federal government should also support research to develop improved processes and methods in the following nontechnology areas:

• Assessment of economic factors, such as taxes, fees, and subsidies established by the government, that influence (1) the demand for and the supply of air transportation services and (2) key decisions made by organizations and individuals involved in the provision and use of the air transportation system.

• Modification of regulations, certification requirements, and operating procedures.

• Prediction and resolution of conflicting objectives of different stakeholders in the air transportation system.

• Understanding societal concerns about aircraft noise and emissions.

Recommendation 3-1. Value of Modeling and Simulation. Federal agencies involved in modeling and simulation of the air transportation system should make complementary use of field tests, laboratory tests, modeling, analysis, and simulation to improve their ability to (1) measure systemwide behavior of the air transportation system, (2) assess the performance of proposed operational concepts, technologies, and other changes, and (3) make informed investment decisions that reduce the schedule, cost, and technical risk of system improvements.

Recommendation 3-2. Management of System Models. Federal agencies that support research in aviation system models should improve their coordination, especially with regard to the following:

• Ensuring that the federal investment for research and development in aviation models focuses on key issues, avoids unnecessary duplication, and encourages cooperation among developers.

• Encouraging participation of industry and academia in modeling and simulation research and development relevant to government needs.

• Establishing widely accepted criteria for the maintenance and validation of models.

• Identifying models that are most important to government policy decisions.

• Making those models more widely available to users inside and outside government.

• Ensuring that modeling and simulation results are used appropriately by decision makers involved in developing the future aviation system.

Recommendation 3-3. System Modeling Research. The government and other interested parties should support additional research in the following critical areas:

• Improving the interoperability of high-fidelity, detailed, data-intensive, long-run-time models of the U.S. air transportation system and the higher-level fast-time, abstract models necessary to analyze overall system performance under a variety of different assumptions so that both types of models can be brought to bear on relevant problems. (It may be feasible to develop models with adjustable resolution that can simplify variables for faster run time when those variables are critical to the analysis being performed.)

• Modeling and simulation methods suitable for safety analysis, which inherently require a detailed level of modeling that includes all the factors that contribute to safety, including human performance and sociotechnical aspects of the system. (Additional fundamental research and development is required before these methods can enter widespread use. New approaches should be pursued using systems theory as well as new nontraditional chain-of-event models.)

• Modeling demand and demand allocation for air transportation services, particularly as it relates to airline schedule changes, including city-pairs, routes (including altitudes and way points), time of day, and the establishment (or elimination) of hub airports. (Dynamic interactions between changing or radically new operational concepts and technologies and user behavior, as they relate to all modes of transportation and other factors external to the air transportation system, must be better understood to ensure the right problems are being addressed.)

• Requirements, methods, and standards for validating individual models and suites of models.

• Understanding how to connect models to form a suite of system models that includes nonlinear dynamic interactions and emergent properties.

• Understanding the role of humans in the aviation system of the future and how to communicate this understanding in a convincing and supportable way. (Including computational human performance models in current simulations and using human-in-the-loop simulations is critical.)

Finding 4-1. Advanced Aircraft Technology. Improvements in aircraft performance are critical to achieving neces-

sary improvements in almost every aspect of the overall performance of the air transportation system. Innovative long-range research leading to the implementation of new operational concepts is also required for the air transportation system to take full advantage of gains in the performance of commercial aircraft.

Recommendation 4-1. Aircraft Research and Technology. To improve the performance of aircraft through 2025, federal agencies should continue to support research leading to evolutionary improvements in aircraft performance. Looking out to 2050, however, research should support innovative concepts aimed at major advances in performance. In addition, agencies should continue to monitor research in related emerging technologies, such as nanotechnologies, and support research aimed at aircraft applications as emerging technologies mature. The areas listed below are prime candidates for this kind of long-term research.

• Analytical tools, advanced technologies, and the fundamental science behind both, to reduce the need for costly hardware testing and to more easily achieve overall research goals (especially in emerging technologies).

• Composite materials with improved qualities that would increase their use in airplane structures and reduce aircraft weight.

• Environmental consequences of aircraft noise and emissions locally, regionally, and globally, to better understand those consequences and support the establishment of better informed priorities and goals for noise and emissions reduction that (1) reflect the need for integrated approaches (involving advances in airframes, engines, and operational procedures) to meet environmental goals and (2) accurately account for the tradeoffs among different environmental goals and different approaches to achieving those goals.

• Low emissions combustor technology, to (1) reduce substantially emissions of NOx and particulate matter at airports (to improve local and regional air quality) and at cruise altitudes (to reduce global climate effects) and (2) reduce emissions produced by engines with high pressure ratios.

• Nanotechnology, to explore its long-range potential for dramatically enhancing aircraft performance through the development of advanced avionics (computing, sensors, and active distributed controls) and high-performance materials.

• Nontraditional aircraft configurations, including but not limited to (1) the blended-wing-body and (2) the strut-braced or joined wing, to improve aircraft productivity and efficiency and reduce noise and emissions.

• Passive and active control of laminar and turbulent flow on aircraft wings (laminar flow to increase cruise efficiency and turbulent flow to increase lift during takeoff).

• Nontraditional power and propulsion concepts and technologies, especially concepts and technologies that support the use of alternative fuels, such as fuel cells (which may have application as auxiliary power units in the foreseeable future) and high-density storage of hydrogen to improve the feasibility of using it as a propulsion fuel.

• High-temperature engine materials and advanced turbomachinery, including (1) lower speed, highly loaded, fan drive turbines and fan reduction gears; (2) very large fan systems, which require advances in manufacturing and material systems; (3) boundary layer control on turbomachinery airfoils, to improve component efficiency and packaging; (4) aspirated turbomachinery components, which could greatly reduce noise and improve component efficiency; and (5) other innovative concepts, such as interturbine burning or volume cooling ahead of or in the compressor by means of a mist of water or other coolant.

Recommendation 5-1. Process for Change. Establish air transportation as a national priority with strong, focused leadership. Air transportation system technology planning and development should be done in the context of a process driven by the needs of system users and the nation as a whole:

1. Implement a public/private process for change, as follows:

   • Designate a federal agency or office to provide strong leadership in overcoming the challenges faced by the U.S. air transportation system.

   • Establish an interagency process for developing and achieving a widely endorsed long-term vision of the air transportation system that includes a clear set of guiding principles and a strategy for overcoming transitional issues.

   • Document the process.

   • Coordinate action and resolve disputes among stakeholders in the aviation community with different concerns and priorities (e.g., manufacturers and operators; executives and employees; pilots, controllers, and passengers; local, federal, and state governments; regulators; the military; and general aviation).

   • Gather and analyze feedback on how well the process is working from the perspective of all interested parties, especially when conditions change, to identify problems before serious incidents or disruptions occur and to recognize new opportunities.

   • Formally review the process and process outputs at least every 4 years.

   • Update the process.

2. The output of the process should include the following:

   • A better understanding of future demand for air transportation to make sure that changing trends will be detected as soon as possible.

3. A comprehensive suite of system models should be developed, validated, and maintained to support informed decision making throughout the process. Models should encompass the following:

   • demand

   • economics

   • environmental effects

   • existing and new technologies

   • human performance

   • interactions with other modes of transportation

   • new operational concepts

   • organizational factors

   • security threats and preventive measures

   • system engineering

   • transition (from old to new technologies, systems, and organizational structures)

4. A commitment should be made to support a stable long-term research program to provide the knowledge, tools, and technologies needed throughout the process. At a low level, the research program should investigate innovative research ideas that challenge accepted precepts.

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