A Simple Method for Calculating L_AE of Helicopter Noise

Abstract

We considered a method for calculating the sound exposure level (L_AE) of helicopter noise. It was assumed that helicopters have no directivity and that the propagation of sound can be expressed in a simple function of distance from an observation point to a sound source. We derived a formula for L_AE by integrating the sound energy along a finite or an infinite flight segment. And we classified the value of power level into three groups by the maximum takeoff weight. The values calculated from the formula agree with the results of test flights in which three types of helicopters each took three moving operations of approach, takeoff and level flyover.