INM reliability on single flight noise prediction

FAA Integrated Noise Model is worldwide used to foresee medium-long term average noise levels around airports. Italian Airport Noise Committees use INM in what-if analysis for single flight in order to determine the best takeoff procedures, either in term of profile analysis or track analysis. The aim of the study about INM reliability is to determine the single flight prediction error comparing INM output levels and NMS, Noise Monitoring System, measured levels. The case of Milan Malpensa International Airport has been studied. NMS time -correlation between radar and noise data, according to minimum distance criterion, has been provided by the Airport Noise Observatory. Malpensa NMS meteorological and radar data had been input in INM to determine flight by flight takeoff procedures and to reproduce 3D paths. Airport Noise Committee has been asked to provide performance data of the most common aircrafts in order to reduce the difference between real and simulated flight. GIS, Geographic Information System, has been used to handle and to represent geo-referenced data; in particular, radar tracks have been reproduced over the NMS terminals (set up as Location Points in INM outputs) and a statistical sample of NMS data has been selected.The final step consists in the determination of error as function of spatial parameters as lateral distance and elevation angle.