ANSI - American National Standards Institute
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Will Supersonic Passenger Jets Take to the Skies? Voluntary Standards May Help


New York, Jan 24, 2007

Supersonic jets are back. Two U.S. companies are taking a serious look at breathing new life into the niche market left open after the Concorde took its final flight in 2003. If all goes well, the new supersonic jets could begin boarding as early as 2012. Voluntary standards may help these high-speed planes to take off.

Supersonic aircraft travel at velocities greater than the speed of sound and at higher altitudes than subsonic airplanes. Such extreme conditions introduce special environmental factors that need to be considered in the design and operation of environmental control systems (ECS) for supersonic jets. ANSI member SAE (the Society of Automotive Engineers) has published a standard specifically designed to address these special considerations.

SAE AIR 746B, Environmental Control for Civil Supersonic Transport, assists in the design and installation of ECS that maintain a controlled environment within specified operational limits of comfort and safety. The standard addresses such factors as pressure, temperature, conditioned air velocity, vibration, and audible noise, among other important environmental considerations.

What happens at high altitudes can also be felt on the ground. When an aircraft exceeds the speed of sound, the air in front of it is compressed to the degree that it forms a shock wave. When this wave reaches the ground, it is heard as a double bang known as a sonic boom. For its difficulty in meeting U.S. noise regulations, the Concorde was primarily confined to flight over oceans. The new jets would make use of an innovative design that is expected to reduce the sound wave to levels compliant with federal noise regulations.

A recently updated standard from the Acoustical Society of America (ASA) may be able to help. ANSI S12.7-1986 (R2006), Methods for Measurements of Impulse Noise, describes methods of measuring and reporting on sonic booms and other impulse noises. Data which may be reported include characteristics of the time variation of the sound pressure and sound exposure level.

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