Prediction of aircraft noise around airports by a simulation procedure

An aircraft noise simulation procedure is described in which the flight path of an aircraft is represented by a series of discrete points passed at constant time intervals. The airspeed, engine power, and spatial orientation of the aircraft together with the spectrum and directivity of the emitted sound are calculated for each point using an operational and acoustic data base. Ultimately, sound propagation laws are used to calculate the noise time history at a fixed location on the ground as well as the related single event noise level. It is found that the noise durations calculated by the simulation procedure are in agreement with measured data and with a theoretical relation obtained by a model study. It is also shown that the sound exposure in the vicinity of a 180-deg turn differs from that of a straight fly-by at the same distance by up to 1.5 dB.