Accuracy of Noise-Power-Distance Definition on Results of Single Aircraft Noise Event Calculation

Aircraft performance and noise database together with operational weights (depending on flight distances) and operational procedures (including low noise procedures) significantly influence results of noise exposure contour maps assessment in conditions of real atmosphere. Current recommendations of the Standard SAE-AIR1845A allow the definition of flight profiles via solutions of balanced motion equations. However, differences are still supervised between the measured sound level data and calculated ones, especially in assessing the single flight noise events. Some of them are well explained by differences between balanced flight parameters (thrust and velocity first of all) and monitored ones by the traffic control system. Statistical data were gathered to make more general view on these differences and some proposal to use them in calculations has been proven. Besides, the real meteorological parameters provide inhomogeneous atmosphere conditions always, which are quite different from the main assumptions of the SAE-AIR1845A, stipulating inaccuracies of sound level calculations.

Automated summary

Aircraft performance, noise database, operational weights, and procedures all have significant impacts on the assessment of noise exposure contour maps in real atmosphere conditions. Current recommendations allow defining flight profiles through balanced motion equations, but differences between measured and calculated sound levels still exist, especially in single flight noise events. Statistical data have been collected to understand and potentially use these differences in calculations. Additionally, real meteorological parameters always provide heterogeneous atmospheric conditions which may lead to inaccuracies in sound level calculations based on standard assumptions.