Weather Specific Noise Abatement Procedures: A Case Study of Departure Procedures for Runway 4R at Boston Logan Airport

Abstract

Although weather is a significant factor in the noise impact of aircraft operations, noise abatement procedures have traditionally been designed for “an average day.” In this paper, we present the details of NOISIM (a model that is used to predict the effects of weather on aircraft noise) and show through a validation study that the model accurately predicts measured noise levels (the model predicted peak noise levels were within 3 dBA in 95% of the cases and sound exposure levels were within 1 dBA in 95% of the cases). We then use the model to determine the effect of weather on aircraft noise impact and illustrate how knowledge of these relationships might enable changes in flight procedures. First, a parametric study is used to illustrate the significant effect that weather has on aircraft performance and noise propagation, and to provide motivation for more explicit consideration of weather in both the design and selection (in daily operation) of noise abatement procedures. Second, a case study of the departure procedure for runway 4R at Logan International Airport in Boston is used to illustrate how the number of people impacted by a sound exposure level greater than 70 dBA can be reduced by almost 56% from approximately 285,000 (for the existing procedure) to approximately 120,000 (for a weather-specific departure procedure).