Estimating Active Space Noise Extent from Two Aircraft Weight Classes over the Great Smoky Mountains National Park

The natural and cultural components of the acoustic environment are a resource intrinsic to parks and protected areas and are critical to wildlife and the visitor experience. However, noise degrades the natural acoustic environment, and aircraft introduce spatially extensive noise into such environments. This study examined aircraft noise events at Great Smoky Mountains National Park, U.S., for different jet aircraft types categorized as “Light” (<20,000 pounds) and “Heavy” (>20,000 pounds). Detection distances were determined for these aircraft types by examining the active space of each aircraft’s noise events. The results of this study determined mean detection distances of 15.2 km for “Light” aircraft and 18.3 km for “Heavy” aircraft to the active space boundaries. Increased thrust or jet velocity from the higher mean altitude resulted in a larger active space. From a practical management perspective, to minimize noise impacts on the park’s natural and cultural resources, efforts should focus on “Heavy” aircraft because they produce greater thrust and frequently operate above GRSM. Using detection distances, managers could work with these aircraft operators or airports to reduce thrust and velocity when flying above protected areas and to discuss routing around noise-sensitive areas, especially with low-level overflights.