Maintaining U.S. Leadership in Aeronautics Breakthrough Technologies to Meet Future Air and Space Transportation Needs and Goals (1998) / Chapter Skim
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4 Air Transportion System Technology
4 Air Transportion System Technology
Pages 53-76
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From page 53... ...
The six sections that follow describe potential improvements to information-re~ated technologies, such as complex models of the entire air transportation system, robust and upgradab~e computer software and hardware, communications, navigation, and surveillance systems for ATM and aircraft operations, and externally focused aircraft sensors. New processes and procedures for incorporating these technologies into the system are discussed, as well as the integration of humans and computers in highly automated systems.
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From page 54... ...
commercial transport aircraft is a prominent example. However, regulations intended to promote safety can sometimes become barriers to technological and proceclural changes.' Predicting the impact of technical or operational/procedura~ changes on a comprehensive basis will require improved methods and models for evaluating the safety of potential changes to the air transportation system.
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From page 55... ...
Documentation of the Current System The current air transportation system, which has evolved over the past eight decades, is now one of the most complex operating systems in the world. The major components are listed below: aircraft operated by air carriers, specializecl service providers, general aviation enthusiasts, and the military · public and private airports and intermoda~ transportation connections · aviation regulations and procedures · aircraft and avionics certification · air traffic control personnel, procedures, and technical infrastructure Many existing practices have been strongly influenced by human abilities and human interactions with technology-based systems.
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From page 56... ...
For example, the acceptance of a new display screen for air traffic controllers may be influencecl by the perceived impact of this new technology on the overall size of their workforce. Technology upgrades to air transports that wouIcl improve the overall efficiency of the air traffic control system will only be voluntarily adopted if the economic benefits are apparent to the airlines.
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From page 57... ...
In addition, new methods for subcomponent risk assessment, including computer-aided design tools, would support consistent risk allocation decisions. Development of Fundamental and Integrated Models Once better documentation, an evaluation of current procedural assumptions, and a better assessment of tolerable risk are available, fundamental models of the air transportation system should be developed to simulate key system elements and their interdependencies.
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From page 58... ...
U PWARD LY COM PATI B LE AL ROS PAC E I N FO RMATI O N SYSTEMS Upwardly compatible aerospace information systems will be crucial to meeting many NASA goals because information technology is increasingly being used for flight control systems, propulsion control systems, and in the control of many other aircraft systems and subsystems. Better control can lead to reductions in aircraft engine emissions and aircraft noise.
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From page 59... ...
In the face of the increasing importance of software, perhaps the most important goal is the control of complexity. Although modular design and software architectures may seem commonplace in software development, they are essential to evolutionary changes in avionics software.
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From page 60... ...
The approaches under investigation in this program for ground-based information systems and a small number of military air vehicles might also be applicable to the development of software used on board commercial transport aircraft, general aviation aircraft, and the ground-based portions of ATM and communications/navigation/surveilIance (CNS) systems.
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From page 61... ...
Improved software certification will also reduce aircraft costs and the time it takes to deploy new or modified aircraft. Because many of the new general aviation aircraft designed to meet NASA's goal for revitalization of the industry will be software dependent, breakthroughs in software development will be key.
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From page 62... ...
One potential approach is the use of mathematically-based formal methods that enable software designers to predict the behavior of a software system by building mathematical models, just as civil engineers construct mathematical models of bridges. Formal logic provides rules that enable valid conclusions to be drawn from explicit, valid premises or statements about the world.
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From page 63... ...
These methodologies include: formal specification methods, including verifiable high-level languages; formal methods of validating specifications and consequent software; techniques for building and checking models to determine the validity of system components, methods of combining disparate sources of software certification evidence; documentation of safety arguments in the form of safety cases; and models of human operators and their roles and expectations. These approaches to software development address NASA's air transportation goals related to improved safety, increased throughput, and a revitalized general aviation industry.
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From page 64... ...
In accidents involving commercial air carriers, approximately 45 percent of the crew-related accidents are due to controfIed-flight-into-terrain7. As humans become the limiting element in the critical systems of air transportation, automation must be used to support critical human performance.
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From page 65... ...
NASA's efforts in this area of research should be teamed with other government agencies with an interest in studying human factors, information systems, and the cognitive sciences, such as the National Science Foundation (NSF) , the National Institutes of Health (NIH)
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From page 66... ...
, or a misinterpretation of available information. In the future, the information potentially useful to a pilot's situation awareness will probably be provided from the following sources: ground proximity warning systems and digital terrain maps; wind shear and clear air turbulence sensors; collision avoidance systems; onboard weather radar; high precision guidance and navigation systems; an air-to-ground datalink; realtime satellite-based weather forecasts; air traffic control data; maintenance data; mission or company management data; onboard synthetic vision sensors; and onboard aircraft performance and status sensors.
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From page 67... ...
Although unpiloted commercial transport aircraft may never be used because of a lack of public acceptance, research and technology development focused on unpi~oted operations clutch identify critical guiclance, control, and pilot clecision-making elements that shou~cl be considered in the design of flight management control systems for either piloted or unpi~oted air vehicles. Since the development of unpiloted air vehicles does not truly eliminate the possibility of human error, but shifts the potential for error from the operator to the clesigner, the increased rigor necessary during design wou~cl also benefit both pi~otecl or unpi~oted air vehicles.
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From page 68... ...
PRECISION AIR TRAFFIC MANAGEMENT/AIRCRAFT OPERATIONS Increasing capacity will be a key driver for future high performance ATM systems. An order of magnitude improvement in the precision of ATM and aircraft operations, such as a reduction in airway widths from 4 miles to 0.4 miles, could increase capacity, while simultaneously maintaining or improving safety, for oceanic, en route domestic, and terminal airspace flight operations and could lead to reductions in the cost of air travel.
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From page 69... ...
national airspace system from a centralizecl commancl-ancl-contro! system between pilots and air traffic controllers to a distributed system that allows pilots, whenever practical, to choose their own routes and file flight plans that follow the most efficient and economical routes.
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From page 70... ...
Although these systems have not been widely adopted due to inertia in the air transportation system as discussed early in the chapter, long-term NASA research and technology development focused on precise navigation and surveillance is not likely to speed their implementation. Fully Autonomous Air Traffic Operations "Free flight" promises to further NASA's safety and efficiency goals, but the concept does not completely free aircraft from reliance on ground-based air traffic control infrastructures, especially in terminal areas.
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From page 71... ...
By allowing aircraft to operate more freely and with less cle~ay in terminal areas, engine emissions and aircraft noise would be reduced. Costly takeoff and landing delays would also be reduced for commercial air carriers, enabling a potential reduction in air travel costs.
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From page 72... ...
and have lower runway occupancy times than conventional aircraft. If V/STOL aircraft could be sequenced onto existing airport runways very precisely, and apart from the arrival stream of other air traffic, runway occupancy time per operation would be reduced.
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From page 73... ...
cannot use them for simultaneous, independent operations because of the safety implications of wakes drifting across the runways. Recent increases in separation requirements to compensate for wake turbulence from the heaviest commercial transports has limited capacity at some airports even more.
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From page 74... ...
Other important technological improvements applicable to all air vehicles, such as improved propulsion systems and improved structures and materials, are discussed in Chapter 3. Personal Air Travel A potential area of breakthrough technology that could meet NASA's throughput goal in the long term without extensive technology upgrades to existing airports or the construction of new public airports would be the design and deployment of personal air transportation vehicles that could offer "door-to-door" transportation under all weather conditions.
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From page 75... ...
To the extent that these improvements can provide more precise control of aircraft operations or can reduce the potentially harmful effects of wake vortices, they could also improve aviation safety and operating conditions for general aviation aircraft. In the long term, personal air transportation vehicles could be a breakthrough that would achieve NASA's throughput goal by allowing millions of air travelers to bypass existing airports and air travel infrastructures.
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From page 76... ...
~ 997. Memo to the Committee to Identify Potential Breakthrough Technologies and Assess Long-term R&D Goals in Aeronautics and Space Transportation Technology, Unitecl Technologies, Sikorsky Aircraft, November 5, ~ 997.
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