WASHINGTON, 15 July 2009. Officials with the Federal Aviation Administration (FAA) Noise Division say that airport noise will increase again soon and continue climbing.
Administration officials say this is due to increased growth in traffic in the years ahead, which means more noise. Unless flight operations can be made even more quiet than they are now, noise exposure will increase, they say in a public release this week.
Noise Division experts say future noise reductions will depend largely on advances being developed through the Next Generation Air Transportation System (NextGen).
NextGen initiatives such as New Optimum Profile Descents (OPDs) enable pilots to reduce power, nearly to a glide, as they land their aircraft, FAA officials say. This eliminates the noise from throttling the engines during step-down approaches near the airport. Additionally, Required Navigation Performance allows pilots flying OPDs to maneuver in areas around the airports to avoid congested housing areas on the ground.
Aside from NextGen, the Noise Division's main noise reduction program – CLEEN (Continuous Lower Energy Emissions and Noise) – provides incentives for manufacturers to develop lower-noise aircraft.
In the late 1970s, noise from aircraft affected about 7 million people. According to the FAA release that number has dropped to fewer than 500,000.
The assessment is based on computing the areas surrounding U.S. airports that are exposed, over 24 hours, to an average noise level of 65 decibels or more – at or above the level of normal conversation. The computation takes into account the number of takeoffs and landings, the noise level of each, and whether the activity took place during the daytime or at night, according to the release.
Since the late 1960s and the advent of aircraft engines with higher bypass ratios – which increase the percentage of air that goes through an engine but not through its combustor – aircraft noise levels have dropped 20 decibels. That translates into making only one-fourth as much noise as they did 50 years ago.
