Aerospace America/June 2006, p38~42: Hushing the roar of air traffic growth

*Unless something is done to reduce aircraft noise significantly, the growth of air traffic in the U.S. will be hindered by a lack of new airports and limited runway capacity. Of all aviation-related environmental issues, noise is the number-one concern of the communities surrounding airports, both existing and proposed. This is making the construction of new facilities and the expanded use of existing runways an increasingly political issue. *Today, along with fuel efficiency and safety, noise reduction is one of the key elements of aircraft and engine design. *"Noise is still number one," says Carl Burleson, director of the office of environment and energy at the Federal Aviation Administration. *...the biggest obstacles to building new airports and expanding runway capacity are environmental concerns—with noise at the forefront. *Runway capacity, according to a number of studies, is a primary issue facing the air traffic system, which the federal government predicts will have to handle a threefold increase in passenger growth by 2025. *high-bypass turbofans,...,"was one of the best things that ever happened for aircraft noise, and it was not ac-tually designed for [noise reduction]," says Char-lotte Whitfield, an aeroacoustics specialist at NASA. “It’s about the only time that perfor-mance benefit and noise benefit have gone hand in hand.” *... aircraft and engine makers as well as people in academia and gov-ernment are constantly working on ways to make airplanes even quieter. Their efforts cover a range of initiatives focusing on engines, air-frames, and procedures. NASA is heavily in-volved. Its Quiet Aircraft Technology program, which provides research and funding, aims to reduce perceived aircraft noise by 50% within 10 years and by 75% within 25 years, relative to 1997 levels. *Acoustic treatment to engine inlet; Chevron nozzles added to engine exhaust; Landing gear ; adjusting arrival procedures;...