The Establishment And Application Of Three-dimensional NPD Database

With the rapid development of civil aviation, people's awareness of environmental protection has increased, the issue of aircraft noise has become the focus of civil aviation and public focus. For this situation, most governments and environmental organizations have developed the aircraft noise certification standards to limit aircraft noise levels. A NPD database has built to provide important reference for certification and airport planning.This paper studied the NPD construction method and its application. Which also described the procedures and requirements of the reference and equivalent flight test, including experimental site selection, flight path measurement, data collection, etc. The calculation method of effective perceived noise level EPNL and NPD confidence interval was also briefly introduced in this paper. Since the NPD data is obtained from the equivalent flight program,the paper made a detailed study of the cross-section equivalent flight procedures, through specific experimental data to determine the method focuses on the entry point of the take-off stage. Based on the measured noise data of a certain type of aircraft, the detailed description of constructing NPD database was introduced, which include access to NPD curve and fitting equation and interactive system based on Excel VBA, in which NPD data can be easily added and inquired, it can also predict the noise level corresponding to a range of power and distance, which plays important role both for aircraft noise certification and airport planning.