What steps are being taken to reduce aviation emissions in the longer-term?

The pace of technological change across the industry is increasing. New engine designs are improving fuel efficiency further, while simultaneously reducing NOx emissions. New aircraft designs improve aerodynamics and reduce weight thereby improving fuel efficiency, reducing all pollutants at the same time. New air traffic control technologies, like new aircraft designs, reduce emissions by reducing fuel consumption (the effect on individual pollutants depends on the phase of flight most effected).

And new management strategies like load management planning and code sharing are being used to optimize the entire system’s operation. With regard to engines, there are complex emission interrelationships that make it difficult to modify their design as a mitigation strategy since it forces a tradeoff among individual pollutants as well as between emissions and noise. For example, high-bypass turbofan engines were introduced to reduce noise and improve fuel efficiency. They require higher engine pressure ratios, which increase engine temperatures, and hence generate more NOx. It has only been in the past 25 years that the resulting NOx increase became a concern.

FAA and other stakeholders have recently initiated an effort to better understand and quantify these interrelationships in an environmental design space.” Eventually this will lead to guidelines for setting long term goals and standards that optimize overall environmental performance and avoid unintended consequences.

Aircraft design improvements mostly fall into one of three areas: aerodynamics, weight reduction, and control systems. Continued improvement in all areas is expected in the future45. Some of the technologies in development for aerodynamic improvements include the design of winglets for wing tips, which reduce turbulence and vortex generation by the wings, laminar flow controls or systems for wing surfaces to reduce drag, and improved manufacturing techniques that will produce smoother surfaces.

New and improved metal alloys and composite materials are being developed to reduce aircraft weight while simultaneously improving structural performance. Significant improvement of control systems has come about by replacing mechanical and hydraulic systems with electrical systems, which often reduce system weight while providing more precise control. Improvements of these systems and development of new systems for enhanced flight stability will contribute to improved overall fuel efficiency. Aircraft technology development and capital turnover follow relatively long cycles, which limits the pace of fundamental changes in design.

It takes approximately 10 to 15 years for fleet average fuel efficiency to equal the efficiency of the newest aircraft46. However, the ongoing evolutionary change in technology has realized substantial benefits over time. According to the Intergovernmental Panel on Climate Change, in their report Aviation and the Global Atmosphere47, aircraft fuel efficiency has improved by 75 percent in the past 40 years through improvements in airframe design, engine technology, and rising load factors.

While progress in the near- and mid-terms is expected, the most significant opportunities for emission reduction lie in the future when we can derive benefits from aggressive research goals. FAA, EPA, ICAO, and many other groups have been working to elucidate and characterize the environmental issues for some time while NASA is directing a research program aimed at significantly cutting emissions from aircraft engines.


What steps are being taken to reduce aviation emissions in the longer-term?

The pace of technological change across the industry is increasing. New engine designs are improving fuel efficiency further, while simultaneously reducing NOx emissions. New aircraft designs improve aerodynamics and reduce weight thereby improving fuel efficiency, reducing all pollutants at the same time. New air traffic control technologies, like new aircraft designs, reduce emissions by reducing fuel consumption (the effect on individual pollutants depends on the phase of flight most effected). And new management strategies like load management planning and code sharing are being used to optimize the entire system’s operation. With regard to engines, there are complex emission interrelationships that make it difficult to modify their design as a mitigation strategy since it forces a tradeoff among individual pollutants as well as between emissions and noise. For example, high-bypass turbofan engines were introduced to reduce noise and improve fuel efficiency. They require higher engine pressure ratios, which increase engine temperatures, and hence generate more NOx. It has only been in the past 25 years that the resulting NOx increase became a concern. FAA and other stakeholders have recently initiated an effort to better understand and quantify these interrelationships in an environmental design space.” Eventually this will lead to guidelines for setting long term goals and standards that optimize overall environmental performance and avoid unintended consequences. Aircraft design improvements mostly fall into one of three areas: aerodynamics, weight reduction, and control systems. Continued improvement in all areas is expected in the future45. Some of the technologies in development for aerodynamic improvements include the design of winglets for wing tips, which reduce turbulence and vortex generation by the wings, laminar flow controls or systems for wing surfaces to reduce drag, and improved manufacturing techniques that will produce smoother surfaces. New and improved metal alloys and composite materials are being developed to reduce aircraft weight while simultaneously improving structural performance. Significant improvement of control systems has come about by replacing mechanical and hydraulic systems with electrical systems, which often reduce system weight while providing more precise control. Improvements of these systems and development of new systems for enhanced flight stability will contribute to improved overall fuel efficiency. Aircraft technology development and capital turnover follow relatively long cycles, which limits the pace of fundamental changes in design. It takes approximately 10 to 15 years for fleet average fuel efficiency to equal the efficiency of the newest aircraft46. However, the ongoing evolutionary change in technology has realized substantial benefits over time. According to the Intergovernmental Panel on Climate Change, in their report Aviation and the Global Atmosphere47, aircraft fuel efficiency has improved by 75 percent in the past 40 years through improvements in airframe design, engine technology, and rising load factors. While progress in the near- and mid-terms is expected, the most significant opportunities for emission reduction lie in the future when we can derive benefits from aggressive research goals. FAA, EPA, ICAO, and many other groups have been working to elucidate and characterize the environmental issues for some time while NASA is directing a research program aimed at significantly cutting emissions from aircraft engines.