Air traffic in the tension between growth, technology and sustainability
Air transport has become an important factor for mobility and prosperity since the first flight of the Wright brothers in 1903. It generates about 3.5% of world GDPs (GDP). This corresponds to the GDP of Brazil (the seventh largest economy in the world). Overall, the industry employs directly about 9 million people - indirectly already over 57 million .
Approximately 1400 Airlines transported in 2013 approximately 3.1 billion passengers and 50 million tons of cargo on an infrastructure of 3,900 airports and 180 air traffic control centers. The fleet consists of 2013 about 28,000 commercial aircraft in service. Overall, different sources reports that about 125,000 civil and military aircraft as well as helicopters (> 3,5to) are operated.
The global air traffic has become through rigorous regulations from the authorities and the global network the fastest and safest system of transportation. It connects people and cultures, enables global business activities and ensures the supply of goods and services worldwide.
Global air traffic is responsible for about 2% of total CO2 emissions (705mio. Tons).
Recent studies estimate that the global air traffic will double again in the next 20 years, thereby further 30,000 commercially used aircraft, are required by replacement and additional growth. Add to this demand for further business jets, turboprops, helicopters and military platforms and approximately 80,000 new aircraft in the coming decades are needed in service.
Thus, the CO2 emissions would increase significantly.
In the past 40 years, specific consumption already has been reduced by approximately 70% in engines. This corresponds to an annual improvement of 3% and has made air travel more comfortable, safer and more environmentally friendly overall.
The industry has set itself the goal from 2020 to make growth "carbon-neutral" and to reduce the emission of CO2, relative to 2000, by 75% from 2050.
To achieve this goal, in the past 7 years, a variety of new aircraft and engine platforms have been developed. In the short and medium-haul Airbus A320neo family, the Boeing B737MAX family, the Bombardier C-Series, the Irkut MS21 (Russia), the Comac C919 (China) and the E-Jet family of Embraer as well as the Japanese Mitsubishi MRJ are the final development phases and will be Entry into Service from 2014 to 2019. About 12,000 aircraft are fixed ordered to date. They will enter into service within the next decade and sustainably improve the environmental footprint of air traffic.
Two basic engine architectures will drive this new generation of aircraft and have begun to reduce fuel consumption on average by more than 15%.
Developed by Pratt & Whittney concept of the geared turbofan (GTF geared turbofan = or as a product: PurePower PW1000G family) based on a completely new engine architecture: A planetary gear decouples the fan and low pressure turbine. This allows two components - the fan and low pressure turbine - an optimized operating in a more efficient RPM range and leads to higher propulsive efficiency and a very high bypass ratio of 12: 1. The concept also leads to a significant reduction of noise (24dB vs kum 2000.): The perceived noise level is halved and the so-called 75dB noise contour at airports reduced by over 70%.. That the immediate noise around the airport area is significantly reduced - in some airports even captured to the airport area. A remarkable lower number of components used in the low pressure system also reduces maintenance costs by up to 20%.
CFMI (a 50% / 50% joint venture between Safran and GE) keeps on the consistent further development of conventional technologies. The LeapX engine family achieve desired reductions in consumption due to higher combustion temperatures in combination with optimized material usage at comparable propulsion and bypass ratio values. For example, special 3D composite materials used in the fan to reduce weight and increase efficiency, while lighter high-strength single crystal superalloys are used in the hot high pressure turbine. The use of 3D production process (so called additive manufacturing) continues to provide weight and cost optimization in the LeapX engine family.
In widebody new engine technologies have been developed in recent years by the Airbus A380, the Boeing 787 Dreamliner and 747-8. The engines of the Rolls Royce Trent family, the Engine Alliance GP7000 and the General Electric GEnx family are already in operation worldwide and reduce CO2 emissions compared to the previous models from the 80s significantly. In development are the Airbus A350 (EIS2015), the A330NEO (EIS2017) and the Boeing B777X (EIS from 2019). The developed of these large aero-engines from Rolls Royce (TrentXWB, T7000) and General Electric (GE90X) leads to more efficient and reduced specific fuel consumption by a another 15%.
Through the use of these new technologies in engine the basis for the goals set in 2050 is plugged-in already in this decade.
The next generation of engines is expected to be in service in 15-20 years and will merge the two concepts (GTF and optimized material use) again. Additionally, additive manufacturing (3D printing) options can halve the weight of an engine in the future by optimized bionic designs.
Also, in aircraft and system designs the concepts for fuel cells, laminar flow guidance, lighter cabin configurations and higher electrification (more electrical aircraft) are under development, their use will lead to lighter and more efficient aircraft for the next generation. In addition, there are some other promising technologies in the development pipelines of the industry. Their usage will make it possible to achieve the desired CO2 goals for 2050.
In addition to the technological innovations of the CO2 contribution is improved by optimized and shortened routes and fuel-efficient air traffic approaches. However, this requires global political conditions which has to be installed to provide further sustainability into focus.
Sustainable produced fuels, so-called. Biokerosene, is the third topic to improve the CO2 profile of aviation on a permanent basis. However, the use of bio-kerosene should not be at expense of safety and global food production. Overall, sustainability in all stages of the process must be critically examined and questioned. Meanwhile, many airlines have launched test programs.
The first conventional introduction is expected no earlier than 2015 with a mixture of max. 50% bio-kerosene on individual routes. The necessary capacity to produce the required quantities will be available no earlier than 2030. However, a major advantage of using bio-kerosene is the use of existing ground infrastructure (eg pipelines and supply at the airport) and airborne by using existing aero-engines..
Due to high investments and security requirements in the aerospace development cycles over 15-20 years are common. They are much larger than the product life cycles of ground mobility systems like automobiles and railways.
All in all, the international discussion on the sustainable use of global resources and the related "man-made" CO2 pollution of the atmosphere in aviation led to the accelerated development of new technologies and systems. Also a discussion to fundamentally rethink all concepts of operation in aerospace and air traffic has started.
However, further development steps in the aviation system are necessary and technically possible. Industry and government must continue to provide sustainable concepts and develop sources of funding to continue the develop of air traffic. Air traffic is a key source of mobility and global wealth and all future developments hast o consider a minimal consumption environmental resources.
Sustainability has become a major issue in air traffic. In future it will become second measure after security for the key development objectives of the industry.
Klaus Mueller,
Kmue-Consult, Principal
km@kmue-consult.de