PART II:
STATUS AND OUTLOOK BY INDUSTRY SEGMENT



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century PART II: STATUS AND OUTLOOK BY INDUSTRY SEGMENT

OCR for page 39
Aeronautical Technologies for the Twenty-First Century This page in the original is blank.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century 2 SUBSONIC TRANSPORT AIRCRAFT INTRODUCTION Although U.S. advanced subsonic transport aircraft continue to surpass all foreign competition in total sales, U.S. market share has been declining significantly. This chapter describes the current market for large subsonic aircraft and projects how the market is expected to change over the next several decades. The White House Office of Science and Technology Policy's Aeronautical Policy Review Committee issued a report in 1985 that emphasized advanced subsonic aircraft over both supersonic and transatmospheric aircraft partly because subsonic technology can generate the resources needed to exploit ensuing opportunities in supersonic and transatmospheric flight.1 It is the opinion of the Committee that this same order of emphasis should be met and maintained in current programs and into the next century. The technologies that are needed to enable the United States to compete effectively in the advanced subsonic transport market are discussed and recommendations are given regarding the role of the National Aeronautics and Space Administration (NASA) in furthering those technologies. The boxed material summarizes the primary recommendations discussed in this chapter and the benefits to be gained from research and technology aimed at advanced subsonic transport aircraft. In the current (1992) aeronautics budget, NASA devoted $93.5 million to research and technology efforts aimed specifically at advanced subsonic transport aircraft. Also, as described in Chapter 1, some portion of NASA's basic technology effort, called "critical disciplines," will contribute to this vehicle class as well. This level of funding is of the same order as that currently devoted to High-Speed Civil Transport (HSCT) research, which is primarily intended to investigate environmental concerns. As the nation's priorities are reevaluated in light of the recent changes in the world situation and the growing importance of economic competition, the emphasis placed by the Europeans on the importance of technology development to support 1   Executive Office of the President. 1985. National Aeronautical R&D Goals: Technology for America's Future. Report of the Aeronautical Policy Review Committee, Office of Science and Technology Policy. Washington, D.C.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century subsonic aircraft, and the importance of subsonic transport aircraft to the global market, it stands to reason that this level of funding should increase, both as part of an overall increase in the NASA aeronautics budget, and in relation to other categories of aircraft. CURRENT INDUSTRY STATUS As noted earlier, the world air transportation system in which U.S. products compete (excluding Eastern Europe and the former Soviet Union) flew more than 1 trillion revenue passenger-miles in 1990, and traffic is expected to approximately double each decade. Although sales of U.S.-produced transport aircraft totaled $27 billion in 1990 (then-year dollars) and grew to almost $35 billion in 1991 (then-year dollars),2 the share of the global market captured by U.S. producers, based on orders for transport aircraft, declined from 87 percent in 1980 to 64 percent in 1989.3 By 1990 the United Kingdom, Germany, and France had invested approximately $26 billion in the Airbus Industries consortium for research, development, certification, production, and price support of the A-300 family of aircraft. To date, the A-300, A-310, A-320, A-330, and A-340 series has captured approximately a quarter of the world market and moved Airbus Industries to a position in the industry ahead of McDonnell Douglas and second only to Boeing. Airbus Industries forecasts that by 2006 it will have captured 35 percent of the market.4 Furthermore, Pacific rim countries—Japan, Taiwan, and Korea—have begun to devote significant resources as well and can be expected to increase their involvement in the market accordingly. The technology of subsonic transports has progressed enormously since the introduction of the first jet transports in the late 1950s. Major improvements have been effected in safety, navigation, thrust management, aircraft control, flight path control, engine noise, engine emissions, and all-weather operation. Also, fuel burned per aircraft seat has decreased dramatically over the last 30 years. For example, in the long-range cruise mode, fuel consumption has decreased by more than 64 percent for aircraft having design ranges less than 4,000 miles (Figure 2-1)5 and by more than 55 percent for aircraft with design ranges greater than 4,000 miles (Figure 2-2). This is significant because a decrease in fuel costs, either through lower prices or greater efficiency, relates directly to an operator's bottom line. In 1990, U.S. air carriers consumed 14.9 billion gallons of jet fuel at a cost of nearly $11.5 billion. Although this fuel cost represented, on average, only 17.6 percent of operating expenses, even Recommendations General NASA should increase its investments in research and technology development to support future subsonic transports to reflect the importance of this segment of the market. Specific NASA should plan and execute a major technology development and validation activity for advanced subsonic transports that is more extensive than that proposed for the HSCT program. This should include: improvements in operational performance of subsonic transport aircraft; and complementary, cohesive, long-term cooperation with academia and industry. 2   Aerospace Industries Association of America. 1991. Aerospace Industries Association 1991 Year-end Review and Forecast. Washington D.C. 3   Gellman Research Associates. 1990. An Economic and Financial Review of Airbus Industries. Prepared for U.S. Department of Commerce International Trade Administration. Jenkintown, Pa. 4   The Aerospace Research Center for the Aerospace Industries Association of America. 1991. The U.S. Aerospace Industry in the 1990s—A Global Perspective. Washington D.C. 5   Illustrations in this chapter are based on data provided by the Boeing Commercial Airplane Group and the McDonnell Douglas Aircraft Company.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-1 Fuel burn comparison for short- and medium-range airplanes (design range ≤ 4,000 nautical miles). a relatively small reduction (e.g., 1 percent) would result in more than $100 million reduction in operating costs. The significant increases in performance realized in the past have been due, in part, to increasing size (economy of scale) and, in part, to improvements in virtually all disciplines that support the design, manufacture, and operation of aircraft. Dramatic improvements in reliability and ease of operations have led, in many cases, to two-man cockpit crews, with a resultant decrease in operating costs. Although aircraft prices are increasing, based on cost per pound of empty operating weight (shown in Figure 2-3), direct operating costs (as shown in Figure 2-4) have remained approximately constant because of the offsetting effects of reductions in fuel burned. Approximately half of the airlines' direct operating costs are ownership costs (acquisition and interest), even if fuel prices double, as shown in Table 2-1. The data in this figure are averages for three classes of aircraft, the 737–400, the 757–500, and the 747–400, operating over ranges of 500, 1,000, and 2,000 nautical miles, respectively. In interpreting the numbers in Table 2-1, it should be kept in mind that net profit is a percentage based on the difference between two large numbers. Thus, the percent impact on the direct operating cost (DOC) may have considerable leverage with respect to profit. The net profit (defined as the difference between revenues and cost, divided by revenues) is about 5 percent for a well-managed airline. Thus, for example, a 4.7 percent increase in DOC due to a 25 percent increase in fuel costs would virtually erase the 5 percent profit. Conversely, a 25 percent reduction in fuel costs, through either lower prices or greater efficiency, that produces Benefits of Subsonic Transport Research and Technology Development Cost/Convenience Reduced development costs: Low cost components Technology validation Reduced operating costs: Lower fuel consumption Reduced maintenance Longer airframe and component life Greater dispatch reliability Increased comfort levels for crew and passengers System Capacity Reduced aircraft separation (takeoff and landing, on the ground, and in-flight) Enhanced Category III operations Greater dispatch reliability Environment Reduced noise Reduced emissions Safety Lower accident rate: Reduced human error Reliable automated systems Reduced and predictable aircraft fatigue Aircraft Performance Greater fuel economy Greater speed and range

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-2 Fuel burn comparison for long-range aircraft (design range ≥ 4,000 nautical miles). FIGURE 2-3 Airplane price trends. a 4.7 percent decrease in DOC would nearly double the net profit. This fact shows the leverage attributable to improved efficiency resulting from advanced technology.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-4 Direct operating cost trends. TABLE 2-1 Direct Operating Cost (DOC)—Major Drivers   $0.63 Fuel (1990 Level) $1.20 Fuel   DOC BREAKDOWN (%) IMPACT ON DOC OF 25% CHANGE (%) DOC BREAKDOWN (%) IMPACT ON DOC OF 25% CHANGE (%) Crew 13.3 3.3 11.4 2.9 Maintenance 14.4 3.6 12.3 3.1 Insurance 1.5 0.4 1.3 0.3 Fuel 18.6 4.7 30.3 7.6 Ownership 52.2 13.1 44.7 11.2

OCR for page 39
Aeronautical Technologies for the Twenty-First Century MARKET FORECAST The air transportation system is growing. Industry and government forecasts project an increase of about a trillion revenue passengers each decade—to 2 trillion in the year 2000, 3 trillion in 2010, and 4 trillion in 2020. The McDonnell Douglas Aircraft Company forecasts the possibility of still greater growth (Figure 2-5). FIGURE 2-5 Projected world passenger traffic. Even if constrained by limitations of airports and airways or by a lower level of growth than forecast, revenue passenger-miles are very likely to at least double over the next three decades. By far the largest part of the current and projected air traffic is flown by the subsonic jet transport fleet. In Figure 2-6, the estimated portions of the conservative forecasts of Figure 2-5 are flown by commuter turboprops with passenger capacities less than 100, the subsonic fleet with passenger capacities greater than 100, and a potentially successful high-speed civil transport (HSCT) in the year 2020. There are now 9,000 jet transports in the international commercial fleet; by 2005 this figure is forecast to be 14,000; and in 2020, 19,500 subsonic jet transports if there is an HSCT, 21,000 if there is not. The market for new transports consists of replacing old or obsolete aircraft and satisfying requirements for growth. The forecast market for 1991 to 2005 is for 9,000 transport aircraft worth $600 billion in sales in 1990 dollars. The follow-on market to the year 2020 will be comparable—more than a trillion dollars in three decades. The international market for transport aeronautical products vastly exceeds that for any other category of U.S. manufactured goods.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-6 Potential traffic distribution. Currently there are also more than 5,000 turboprop aircraft in service with passenger capacities of less than 100. In the forecast period, this class of service will grow. Though modest in terms of revenue passenger-miles and total sales compared to large subsonic transports, this class of aircraft comprises a large total of the departures and contributes significantly to the congestion problem (Figure 2-7). Aircraft other than turboprops may emerge FIGURE 2-7 Projected worldwide aircraft departures.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century for commuter use and some portion will move into the greater-than-100 passenger class, as represented by the middle portion of Figure 2-7. Transport aircraft used by commercial airlines can be broadly categorized by their seating capacity and their range capability. The solid elliptical-shaped areas in Figure 2-8 depict classes FIGURE 2-8 Number of seats versus range capability. of current short-, medium-, and long-range aircraft identified by symbols that show specific aircraft. The data for current aircraft are extended by the dashed lines to show the probable course of the increase in size and passenger capacity of these categories. The growth in size of transport passenger aircraft, particularly since the advent of wide-bodied designs, has increased the economic potential of large, dedicated all-cargo aircraft. A number of studies have been performed by NASA, Lockheed, General Dynamics, and Boeing of designs for aircraft with gross weights of 1 to 3 million pounds. Though infrastructure barriers exist, no technical barriers were identified in any of the studies. The reasons for the lack of success in this area are economic factors unrelated to the airplane itself. Nonetheless, a comprehensive aeronautics plan for the future should continue to examine the need for large passenger and cargo aircraft to determine whether aircraft technology might become the critical barrier to success.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century BARRIER ISSUES Increased competition within the aircraft manufacturing sector and the pressure exerted on airlines by deregulation and uncertain fuel costs, have caused the development of new generations of aircraft to be increasingly driven by profitability. New aircraft designs incorporate only those features that can convincingly be shown to increase safety, reduce cost, or increase productivity, and any effort to develop advanced technology is viewed from that perspective. Furthermore, future aeronautical development programs not only must provide clear economic improvements, they must do so with minimum environmental effects and with an increase in safety such that the rate of accidents continues to decrease. To meet the challenges of the next several decades, the Committee believes that each of the five areas of need described in Chapter 1 must continue to be addressed. However, for the particular needs of advanced subsonic transports, the Committee has concluded that three of those areas provide the primary new barriers to growth: overall cost, system capacity, and environmental compatibility. This is not to imply that performance and safety should be ignored. For example, it has been pointed out that a long-range, advanced subsonic aircraft with a cruise Mach number of 0.9 may provide a significant competitive edge. Rather, the Committee believes that sufficient safety and performance advancements can be realized by proceeding along the same general paths in structures, propulsion, aerodynamics, safety research, human factors, and cognitive engineering as have traditionally been followed. In contrast, to produce corresponding gains in cost, capacity, and environmental compatibility it will be necessary to rethink a number of the basic assumptions on which the current airspace system is based. Where appropriate, in the following sections the Committee has identified specific goals that it deems to be both necessary and reasonable for overcoming these barriers. Overall Cost It is clear that the acquisition and maintenance costs of transport aircraft must be reduced to compete with increasingly sophisticated foreign competition. A reasonable goal is to reduce these costs by 25 percent over the next two decades, relative to currently produced airplanes. Likewise, operating costs must be reduced. A reasonable goal to bring that about is a reduction in fuel burn per seat of about 40 percent, compared to current airplanes. A 25 percent reduction can be expected from improved engine performance (Figure 2-9) and 15 percent from aerodynamic and weight improvements. Figure 2-10 shows the achieved and anticipated improvements in aerodynamic efficiency from 1960 to 2020. Over the 20 years from 1975 to 1995, aerodynamic efficiency will have increased by less than 10 percent. This trend indicates that through normal evolutionary advances, lift-to-drag (L/D) ratios will reach only 22–25 by 2020. More aggressive application of aerodynamics technology could push this ratio to 28–30 and provide a significant competitive advantage for U.S. aircraft. The historical trends in aircraft weight improvements are not as clear. Improvements have been offset in the past by improved operational performance, which includes greater range,

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-9 Installed turbine engine efficiency (TSFC = thrust-specific fuel consumption). better altitude capability, better low-speed performance, lower noise, wide-body comfort, better cargo handling, improved systems response/redundancy, and longer structural life. For the future, composite structures appear to provide the most attractive improvements (Figure 2-11), but a great deal of research is needed into processes for evaluation, maintenance, and repair of composite structures. Additional features, however, are expected to be added to the aircraft, which will offset some of the gains. At current prices and for an airplane the size of a 747-400, these gains translate into a 26 percent reduction in DOC, as illustrated in Figure 2-12. For a broader range of sizes these goals are shown in Figure 2-13. System Capacity The complexity and congestion of the current airspace system and the corresponding congestion at the world's airports suggest that realizing the expected growth in the advanced subsonic transport market will require a significant change in the approach to accommodating people and aircraft. It is clearly impossible to continue building larger and larger aircraft and to expect current airports to accommodate them. Nor is it reasonable to think that more and more aircraft, with the current level of air traffic control, will be able to fit into the already crowded airspace without seriously affecting safety and convenience. Without advancements in on-board control and warning systems, systems that make better use of global positioning satellites for flight path design, and systems that make it possible to accommodate more passengers and planes both in the air and on the ground, the future of air travel will be one of longer delays and more accidents. Chapters 10 and 11 of this report describe technologies that

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-10 Aerodynamic efficiency. are deemed by the Committee to be of primary importance in providing these required capabilities. Environmental Compatibility The environmental compatibility of large subsonic transports is a major barrier to the growth of the worldwide market and, thus, to the growth of U.S. companies that build this type of aircraft. Although it is impossible to predict the requirements that will be placed on future systems regarding engine emissions, it is clear that they will be significantly more restrictive than current regulations. Similarly, a reduction in noise that is sufficient to satisfy continually more stringent regulations will be essential to remaining competitive over the next several decades. There has also been much discussion regarding the use of exotic fuels such as liquid hydrogen or liquid methane to reduce fuel costs or noxious emissions. The Committee believes that such fuels will probably not be required in the period 2010–2020. Rather, synthetic Jet A-1 fuel can likely be produced from oil shale, natural gas, and coal at significantly lower total costs than these exotic fuels when all factors are considered.6 6   National Research Council. 1990. Fuels to Drive our Future. Washington, D.C.: National Academy Press.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-11 Potential airframe weight savings. NASA'S CONTRIBUTIONS TO ADVANCED SUBSONIC TRANSPORTS The contributions that NASA can make to the development of technology for advanced subsonic aircraft are grouped below into the five categories of need that were defined in Chapter 1: cost/convenience, system capacity, safety, environment, and aircraft performance. As might be expected, much of this discussion overlaps with the corresponding discussion of NASA's contributions to the advancement of HSCT and short-haul aircraft (Chapters 3 and 4, respectively). Although the factors that make an aircraft competitive vary somewhat by category, the technologies that make for better performance, simpler and safer coordination with the air traffic management system (ATM), or reduced impact on the environment tend to be applicable to a variety of aircraft. Thus, the issues discussed in this section may well apply to other categories of aircraft as well. Table 2-2 shows current (1992) funding for advanced subsonic transports by discipline. As discussed in Chapter 1, the Committee was not constituted to recommend specific funding levels for the technologies discussed in this report. Although the percentages shown in Table 2-2 seem appropriate given the wide range of technologies that are likely to contribute to the long-term success of subsonic aircraft, the technologies recommended here and in later chapters will require an increase in funding and possibly a change to the relative funding between disciplines. The precise increase in funding and the corresponding percentages devoted to each discipline should be determined by the NASA Office of Aeronautics and Space Technology as part of a continuing reevaluation of its program. This reevaluation

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-12 Direct operating cost breakdown for the 747–400 (1990 U.S. Dollars). should take into account the needs of industry and the current plans of other government agencies, particularly the FAA. It should be noted that performance improvements required for future advanced subsonic transport aircraft are heavily dependent on the realization of significant advances in avionics and controls. Chapter 10 discusses these issues in detail. Some of the more important ones lie in the following categories: operational all-weather takeoff and landing systems advanced ground control systems integrated ground/air-based collision avoidance systems airborne and ground-based, real-time, weather threat displays and alerting systems cockpit display technology relaxed static stability integrated controls, and active flight controls. Discussion of these points later in the report should not be construed to imply that there are no relevant NASA efforts. In many cases, NASA has productive ongoing programs. No attempt is made here to discuss or evaluate those efforts; rather, the Committee believes that they are not large enough to meet the needs.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century FIGURE 2-13 Direct operating cost goals (range = 1,000 nautical miles, 1990 U.S. dollars). Cost/Convenience The Committee has identified a number of areas in which NASA can contribute to making advanced subsonic transport aircraft more cost-competitive while maintaining the overall convenience of both air and ground systems. In many of the following cases no specific technology will meet the stated goals. Rather, a combination of disciplines, some of which only NASA can provide, must be brought to bear on the problem. Thus, although the search for specific solutions to many of the following issues must remain the province of the private sector, NASA can expect to be a valued partner in the problem-solving process. Aging aircraft require extensive, expensive, and numerous periodic airframe structural inspections to ensure structural integrity. The inspections themselves, the repair of damaged components, and the need to withdraw the aircraft from service for these activities all have unfavorable effects on cost. The economic airframe structural life of jet-powered subsonic transport aircraft as a design requirement has increased from an initial 10 or 12 years for the early designs in the 1950s, through 15 years, and now 25 years for new designs. Pressure for this continuing increase comes from the disproportionate increase in labor costs associated with a given level of inspection and repair. Composite structures promise major improvements in aircraft weight but will not be widely used in commercial aircraft until their cost is reduced and confidence in their structural life has increased greatly. That is, composite structures must not require major modifications to maintain structural integrity during their projected economic life. Clearly, NASA should use its growing expertise with new composite structures to help guide

OCR for page 39
Aeronautical Technologies for the Twenty-First Century TABLE 2-2Advanced Subsonic Transport Funding by Discipline Discipline Current NASA Program (millions of 1992 dollars, percent of total)a,b Systems and operationsc 2.3 2.4% Aerodynamics 12.9 13.8% Propulsion 16.8 18.0% Structures and materials 28.1 30.1% Controls, guidance, and human factorsd 29.4 31.4% Other (aging aircraft) 4.0 4.3% Total 93.5 100.0% Source: NASA Office of Aeronautics and Space Technology. a 1992 funding in real-year dollars, excluding fundamental research not tied to a specific application. b Percentages may not add to 100% due to roundoff error. c Includes both flight systems research and systems analysis studies. d Includes the avionics and controls and cognitive engineering categories discussed in this report. the aircraft manufacturing industry in determining how the greater use of composites can reduce the weight of aircraft without adversely affecting economic lifetime. Also, current European aircraft are deemed superior to U.S.-built designs in their corrosion resistance. NASA should work toward a significant improvement in the understanding of corrosion resistance in an effort to help lengthen the period between mandatory inspections. A major element of airline operating costs is spare parts with the associated maintenance and man-hour costs. NASA should intensify its efforts to improve the reliability and maintainability characteristics of aircraft components, particularly in reducing the complexity of components such as actuators, pumps and valves, and engines. Also, items such as fasteners, connectors, wiring, and reduced-sensitivity avionics should be considered. Basic landing gear components such as wheels, tires, and brakes also contribute significantly to operating costs. In fact, they are the highest maintenance item on a per-flight basis. As aircraft weight increases, landing gear weight and complexity increase disproportionately. If aircraft weights continue to grow as forecast, efforts to simplify the design and reduce the cost of landing gear components will provide increasingly important cost savings. NASA should use its facilities and expertise to contribute to a significant decrease in both the weight and the complexity of landing gear components.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century Modern developments in secondary power systems (i.e., electrical and pneumatic subsystems) may reduce or eliminate the need to use engine bleed air as a power source, thereby reducing fuel consumption. Research in ''power by light'' systems has shown promise, at least for low power levels, but much refinement is needed. In short, secondary power systems should be independent of the operation of the main propulsion engines, although backup systems that are driven by the main propulsion engines should certainly be available. The use of high-performance battery systems being developed for a variety of nonaircraft uses, as well as electrostatics technology, should be explored. NASA should play a key role in developing advanced power technology, for applications in aeronautics, to the point at which industry can begin incorporating it on a large-scale. NASA's current research into advanced power systems for spacecraft may provide applications in this area. Present-day aircraft suffer from cockpit suites designed and manufactured by a number of different companies, which produce mismatches in capability and less-than-optimal performance. Typically, displays and other components are selected by airline operators from various manufacturers, leaving the aircraft manufacturer the very difficult task of integrating the assortment of components. Given this difficulty, manufacturers have begun to explore fully integrated cockpit concepts. Unfortunately, this is an area in which both the Japanese and the Europeans offer significant competition. NASA should help provide the technology needed to stave off this competition. Application of flat panel displays to replace cathode ray tubes, advanced computing and information-sharing technology, integration standards, and applications of advanced human factors can all contribute. Furthermore, a coordinated systems engineering approach to cockpit development will be required to realize the full potential of this technology. A major passenger complaint today is that comfort has deteriorated to very low levels. This can be an increasingly important competitive factor, and some passengers alter their travel routes to avoid certain airlines and take more circuitous routes that offer a higher degree of comfort. In addition to the obvious consequences of inadequate seat width and knee room, it has long been known that prolonged exposure to decreased pressure, low humidity, high noise, and high vibration greatly increases passenger fatigue. It is within current engineering design capabilities to reduce any, or all, of these factors. However, the trade-off between aircraft weight and measures to reduce passenger fatigue presents a difficult decision for the designer. As an example, for every increase in minimum cabin pressure an aircraft requires a corresponding addition of structural weight. The question is whether such an increase in minimum cabin pressure would have any measurable effect on passenger fatigue. Further, no design guidance is available to answer the question of whether the weight penalty is better spent in this way than in using it to reduce noise or vibration, for example. NASA should use its expertise in cognitive engineering to guide the designers of advanced aircraft in achieving real gains in passenger comfort and corresponding gains in the competitiveness of U.S. products. Chapter 1 of this report contains a short discussion of the benefits of reducing the design cycle time for aircraft to get new generations of products to market ahead of the competition. Although the Committee did not consider this issue in detail, it is worth mentioning that a major

OCR for page 39
Aeronautical Technologies for the Twenty-First Century factor in remaining competitive in the advanced subsonic transport market is the ability of aircraft manufacturers and airline operators to adjust rapidly to different passenger desires, changing fuel costs, changing routes, and changing regulations. This parallels the situation in the automobile industry, in which the Japanese can bring a completely new design to market in three years, whereas the U.S. industry takes five. It would be of significant benefit to the U.S. air transport industry if one year could be eliminated from the development time of an aircraft. The difficulty in accomplishing this will be increased by the additional efforts that must be devoted to safety and environmentally-driven items during the design process. The increasingly complicated certification process, although not directly a technology issue, may, nonetheless, produce difficulty in incorporating new technology into aircraft. NASA's role in this effort is unclear, but it is likely to involve no more than being an advisor to industry. System Capacity System capacity was identified in the previous section as one of the primary barriers to growth of the advanced subsonic aircraft market. The Committee has identified a number of areas in which NASA can contribute to increasing the capacity of air and ground systems. To maximize terminal airspace use, aircraft separation currently required to account for wake vortex effects should be reduced. NASA should investigate the potential reductions that can be realized in wake vortex effects through detection and avoidance, through understanding the effects of meteorology, and through reducing of the rotational energy in the vortices by means of aerodynamic design refinements. Better and more reliable electronic and mechanical systems, along with more straightforward maintenance procedures, will materially assist in achieving greater reliability in aircraft. Currently, airlines are capable of 98 percent mechanical reliability in dispatching their planes. With efforts to develop more reliable components and to incorporate a design-for-maintenance approach into the total systems design process, that figure could increase to 99 percent. Similarly, greater reliability can reduce the amount of time aircraft spend on the ground, thereby freeing up airport gates for the next arriving flight and moving more people through the system. Since major increases in the size of current airports are not feasible, a reduction in the physical dimensions of aircraft while on the ground is one approach to packing more aircraft into a limited space. New aircraft in the 700- to 800-seat category are already in the design stage, and a 1,000-passenger aircraft is quite possible by the year 2020. Neither these aircraft nor a reduced sonic boom HSCT will meet current airport dimensional limitations. As noted earlier, the use of suitable satellite and inertial systems, coupled with data links, should be pursued intensively in an effort to eliminate ground-based systems for position fixing. A ground-based system will still be required to provide a check and backup in the event of loss of the satellite system. An additional objective is elimination of the need for a separate collision avoidance system. The ability to provide an even safer level of operation is inherent in the improved satellite/inertial system. Positive four-dimensional control will be needed for the capacity requirements and should ensure no collisions.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century Category IIIb operations are currently possible at only a few runways equipped with the necessary ground aids.7 The use of sophisticated on-board systems, as discussed earlier, will eliminate this dependence and should enable true Category IIIc operations with zero runway visual range. Category IIIc will be required for the higher-capacity system needed for the period 2010–2020 to ensure that air traffic continues flowing smoothly in adverse weather conditions. In addition, advanced ground control systems will be necessary to ensure that aircraft can safely navigate on the ground in bad weather. The attainment of safer and higher-density takeoffs/landings and en route separation requires a reduction in the demands placed on voice radio communications between aircraft and ground. This can be accomplished through air-ground data links for many ATM system messages. A related issue involves the growing use of higher-power ground- or sea-based high-intensity radio field transmitters. The effect of these transmitters on sophisticated aircraft electronics subsystems, particularly those associated with navigation and aircraft control, must be determined. NASA, in conjunction with the Federal Aviation Administration, must continue to work toward incorporating advanced positioning, collision avoidance, and information transfer technologies into integrated on-board control systems for both in-flight and ground operations. Environment The future levels of allowable aircraft noise and emissions are unknown, but whatever they are, future aircraft must satisfy applicable laws, rules, and regulations—and those regulations must be sensible, not arbitrary and uneconomic. For aircraft noise in the 2005–2020 period, a preliminary goal of 10 dB below Stage 3 is a very demanding objective; the final goals must be balanced against economic effects and other risks. A preliminary goal for engine nitrogen oxide (NOx) emissions is a reduction of 20–30 percent. Noise and emissions levels must be controlled without increasing costs or degrading performance. It is the Committee's belief that NASA can and should play a lead role in addressing the problems associated with noise and emissions from advanced subsonic aircraft. Safety Air travel has become remarkably safe because much of industry's and NASA's efforts have focused on safety. The accident rate per departure is the most often cited figure of merit because aircraft risk is largely associated with landing and takeoff operations. The accident rate has stabilized in recent years. However, although the rate is relatively low, an increasing 7   Runway visual range (RVR) is the horizontal distance runway at which the pilot can actually see the landing position. Category IIIb operations imply an RVR of approximately 300 feet. Category IIIc operations imply zero RVR, or essentially zero visibility landing.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century number of operations will increase the absolute number of accidents accordingly, which would be unacceptable. The industry believes that the rate of accidents per departure can be lowered sufficiently to hold the number of accidents per year constant through the next 10 years while still increasing the size of the fleet. Once this goal is achieved, other innovations not currently available will be needed to continue to lower the rate. Because 72 percent of all hull loss accidents are primarily crew related, emphasis on human factors is needed, as discussed in detail in Chapter 11. Since NASA has considerable experience in this area, the agency should provide a great deal of the effort toward pushing the state of the art in aircraft safety. Considerable progress has been made in the area of windshear detection, but false alarms and false indications are still concerns. A fully reliable windshear prediction detection and avoidance system is mandatory for the 2010–2020 time period. As noted in the discussion of system capacity, development of sophisticated on-board inertial and satellite capability, permitting the elimination of ground-based microwave landing systems and instrument landing systems, will also eliminate the need for primary ground-based systems for position fixing (except as a backup in case of loss of the satellite system). NASA should play a major role in the development of a broad range of ATM systems. Development of advanced flight simulators can have a pronounced impact on training and skill maintenance for commercial pilots. Although flight simulators have reached impressive levels of performance and simulation, their development cycle time is usually such that operators do not have access to them when they need them. It is desirable to have flight simulator development proceed along a schedule that matches the aircraft development and delivery schedule. This will also offer future operators the opportunity to uncover operational problems prior to delivery. NASA has considerable expertise in the development and operation of simulators for both aircraft and space systems. It should work with industry to determine areas in which advanced technology can be applied to commercial aircraft simulators. Potential applications include reduced cost, improved reliability, and overall fidelity. Aircraft Performance NASA's role in pushing the state of the art in performance for advanced subsonic transports is clear: aircraft that have greater fuel economy, better lift-to-drag ratios, and lower structural weight are required to keep U.S. manufacturers competitive because they are the primary drivers of cost. NASA is, of course, a major contributor in advancing the technologies that produce those performance improvements through aerodynamics, structures and materials, propulsion, advanced avionics, and information sciences and human factors. Details of how these performance issues should be addressed in the current and future NASA aeronautics program are deferred to later chapters of the report that deal specifically with these disciplines.

OCR for page 39
Aeronautical Technologies for the Twenty-First Century RECOMMENDED READING Boeing Aircraft Company. 1972. Study of the Application of Advanced Technologies to Long-Range Transport Aircraft. Volume I: Advanced Transport Technology Final Results (NASA CR-112092). Prepared for National Aeronautics and Space Administration under Contract No. NAS 1-10703. Consumer Reports. 1991 (July). "The Best and Worst Airlines." General Dynamics, Convair Aerospace Division. 1972. Study of the Application of Advanced Technologies to Long-Range Transport Aircraft. Volume II: Technical Applications (NASA CR-112092). Prepared for National Aeronautics and Space Administration under Contract No. NAS 1-10702. Lange, R.H., R.F. Sturgeon, W.E. Adams, E.S. Bradley, J.F. Cahill, R.R. Eudaily, J.P. Hancock, and J.W. Moore. 1972. Study of the Application of Advanced Technologies to Long-Range Transport Aircraft. Volume I: Analysis and Design (NASA CR-112088). Prepared for National Aeronautics and Space Administration by Lockheed-Georgia Co., Lockheed Aircraft Corp., under Contract No. NAS 1-10701. National Research Council. 1988. Look Ahead—Year 2020. Transportation Research Board. Washington, D.C.: National Academy Press.8 National Research Council. 1990. Fuels to Drive Our Future. Energy Engineering Board. Washington, D.C.: National Academy Press.8 Toll, Thomas. 1980. Parametric Study of Variation in Cargo-Airplane Performance Related to Progression from Current to Spanloader Designs. NASA Technical Paper 1625. Washington, D.C.: National Aeronautics and Space Administration. 8   These reports conclude that the supply of petroleum is adequate through the year 2020 and that if the price rises approximately $70 per barrel, petroleum can be extracted from coal, tar sands, and shale at prices about this level. Boeing studies (and others) show that even at this price level, the equivalent of Jet A-1 will still be the preferred fuel.