TECHNOLOGY ROADMAP FOR THE FUTURE AIR TRANSPORT SYSTEM BEING EFFICIENT AND ENVIRONMENTALLY SUSTAINABLE

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According to global air traffic forecasts the air transport system will double within the next 15 years. Although today’s environmental impact of aviation on climate change is small in comparison to other sectors, the anticipated growth requires substantial enhancements in the emission characteristics of new aircraft and new operational concepts with breakthrough technology improvements. Given the sensitivity of the aviation industry to fuel costs, a highly fuel efficient air transport system is another requirement to achieve economic sustainability. Based on the long-term visions set not only in Europe but also in the US, the presentation will address the key enabling technologies for aircraft design, engines and the operation of aircraft within a future air transportation system achieving these objectives. The conclusion will give an outlook on the global air transport emission balance with respect to level of availability of technology and their possible introduction into service. 1.INTRODUCTION The air transport system is an essential part of the globalized economy of the 21 st century. The development has brought air travel from being a luxury after the World War II to an easy to use and affordable commodity to the turn of the millennium. With the new century new challenges arose for the air transportation system. Aside the tendencies to liberalization and deregulation the focus turned to security aspects following the terrorist attacks of 2001. This topic remains to be addressed, but the security research is on track to develop new strategies to keep aviation a secure transportation system. However, environmental sustainability remains as a big challenge to be solved. In light of the soaring oil price with a doubling in prices for jet fuel within 18 months (between Jan 2007 and June 2008) and the higher awareness for anthropogenic climate change the air transport system has to adapt to these new condition to sustain its expected growth rates and economic profitability. The introduction of fuel saving technologies into the air transport system is very cost intensive and furthermore political measures like the inclusion of air transport into the emission trading scheme add to the burden for the airline industry. The following paper will present a technology roadmap for the future air transportation system pointing out new concepts being both economically feasible and environmentally sustainable. This includes an assessment of the current growth rate of aviation and the environmental impact, current trends in research and development in Europe, an overview over the main technology fields and the accompanying political measures. An assessment of the global impact will conclude this paper. 2.AVIATION GROWTH AND ENVIRONMENTAL IMPACT According to the forecasts of the two largest manufactures for commercial aircraft the air transport system will experience growth rates of 4.9 % [Airbus 2007] to 5.0 % [Boeing2008] in the passenger business and even higher rates in the cargo area (both predict 5.8%) for the next 20 years. Associated with this increase is an expected demand for up to 29,000 new airplanes in the same timeframe. As a result the air traffic will double within the next 15 years Sitraer 7 (2008) LXIVLXXIV LXV (Figure 1). Historical data show that this assumption is realistic. The air transport system proved to be resilient to external crises surviving the oil crises of the 1970s, two gulf wars, economic downfalls, the terrorist attacks of 2001 and large area epidemics like SARS 2002. The air transportation system has more than regained the traffic figures of the pre 9/11 era plus average growth rates. And hopefully this will be true also for the current global crisis of the finance markets. Figure 1: World air traffic growth [Airbus 2007] With this continued growth rate comes one of aviation’s main problems. Although the whole air transport system accounts today only for approximately 2 % of the global man made carbon dioxide emission [IPCC 2000] the growth rate will not be offset by increased fuel efficiency and thus increasing the share of the CO2 impact with added contributions to global warming. This increased impact is furthermore augmented by the fact that aircraft emissions occur in higher altitudes with more severe implications than ground level emission from other transportation sources. To account for this effect the radiative forcing index (RFI) is used. The IPCC assumes the RFI to be between 2.2 and 3.7 for commercial aviation 3 . The RFI and the projected growth rates explain the major effect of the air transport system on global CO2 emission and therefore the need for improvements in fuel efficiency. This need is furthermore intensified by the high fuel prices directly increasing the airline’s operating costs while reducing profitability margins. Because new technologies solving these problems are not readily available further research and development is necessary. Several research programs are currently underway to address these issues. 3 EUROPEAN RESEARCH STRATEGIES FOR THE FUTURE 3.1 ACARE (Advisory Council for Aeronautic Research in Europe) In 2001 the European aviation community recognized the requirement of new technologies for aviation in the 21 st century using a structured approach. Therefore the Advisory Council for Aeronautic Research in Europe (ACARE) was established, a high level group of about 40 representatives from EU member states, the EU Commission, airlines, the manufacturing Sitraer 7 (2008) LXIVLXXIV LXVI industry and academia. In its Strategic Research Agenda 1 (2002) five focus areas where identified: • Quality and Affordability • Environment • Safety • Air Transport System Efficiency • Security Additionally, specific goals were defined to be achieved by the year 2020. In the context of this paper only the goals for the areas Environment and Air Transport System Efficiency are mentioned: ACARE Environmental Goals are • To reduce fuel consumption and CO2 emissions by 50% • To reduce perceived external noise by 50% • To reduce NOx by 80% • To make substantial progress in reducing the environmental impact of the manufacture, maintenance and disposal of aircraft and related products ACARE Air Transport System Efficiency Goals are • Accommodation of three times more aircraft movements compared with 2000 • Enabling 99% of flights to arrive and depart within 15 minutes of their advertised scheduled departure time, in all weather conditions These ACARE goals were furthermore reviewed in the Strategic Research Agenda 2 in 2004, where the main focus areas where confirmed to be still of high importance. The strategic approach was slightly changed to a more holistic approach ensuring the involvement of all stakeholders e.g. airports which were not adequately covered earlier. The second agenda introduced a long term view going beyond 2020 adding promising technology concepts not to be available for the market by 2020. These strategic considerations led to the launch of the Clean Sky Joint Technology Initiative research program by the European Commission which will be explained in the following chapter. 3.2 Clean Sky Joint Technology Initiative Following the ACARE recommendations the Clean Sky Joint Technology Initiative was launched in 2007 by the European Commission in cooperation with the industry, research institutes and other partners within the EU. With a budget of 1.6 billion Euros it is one the largest research programs in the EU, lasting from 2007 to 2013. The main goal is to reach the ACARE goal faster in a concentrated effort compared to the usual industry development cycles of 10 years. Clean Sky’s main goal is to develop six so called Integrated Technology Demonstrators (ITD) in a multidisciplinary approach for each of those demonstrators. The six ITD covering a broad range of the air transportation systems are Smart Fixed Wing Aircraft, Green Regional Aircraft, Green Rotorcraft, Sustainable And Green Engines, Systems For Green Operations and Eco Design. All of them are linked by a common simulation platform called Technology Sitraer 7 (2008) LXIVLXXIV LXVII Evaluator to asses the environmental improvement of the technology developed in the different ITDs using a process based model of the air transport system (Figure 2). Figure 2: Structure of Clean Sky Project [Clean Sky JTI 2008] A large number of goals within the six demonstrators are addressed within the detailed research program. The most interesting ones related to this paper will be mentioned below. In the fixed wing aircraft project the goal is to reduce aircraft noise by 5 to 10 dB and emission from fuel combustion by 10 % to 20 % for medium and long-haul aircraft. This is to be achieved by reducing the wing’s aerodynamic drag using active and passive flow and load control. The other main area of research will be new aircraft configurations due to new engine concepts. For regional aircraft the main objective is the adaption of market ready technologies like the use of carbon fibre materials to fit the requirements of regional aircraft. The aircraft engines account for most of the noise and fuel consumption characteristics of airplanes and for the air transportation system. Therefore the development of greener engines is crucial for reaching the ACARE goals and an important part of the Clean Sky initiative. Within the program up to five full sized engines will be produced evaluating new technologies and concepts. Some of those concepts will be explained here. The Systems For Green Operations demonstrator project is part of the holistic approach within the Clean Sky program.