Does Steep Descent Cut Aircraft Noise?

Noise reduction by trajectory management is one of the options currently considered at several airports around the world. The idea behind a “steep” descent is that the airplane would be further from the receivers on the ground, and thus by “propagation” alone, the noise level at the receiver would be lower. For example, by doubling the source-receiver distance, the noise level would decrease by 3dB. Unfortunately, the solution is not straightforward, as demonstrated later.

Information fed to the media, as in the case of the newspaper cutting shown below, may generate confusion and unrealistic expectations. The journalist incorrectly refers to “jet noise”; we need to consider the overall sound level created by the airplane system.

Figure 1: Newspaper discovery of steeper descent [December 2012]

Figure 1: Newspaper discovery of steeper descent [December 2012]

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