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Without available direct measurements, the only method of assessing the impact of a completely new aircraft or power-plant design is to utilize a reliable prediction procedure. Such a procedure may be able to make use if a limited amount of directly relevant data, for instance, engine test data, or may have to rely entirely upon empirical component prediction procedures. Traditional aircraft noise prediction procedures based on engine static noise data are generally costly in time, since the engine source separation process is not a straightforward task, demanding several side routines to make it feasible. This paper attempts to present a new and simplified approach to assess community noise levels of a new aircraft design based on static engine noise data. The simplified procedure proposes an alternative to the complete engine source separation process, based on the definition of master parameters like jet noise cut-off frequencies, tonal frequencies and resultant broadband spectra.

The Brazilian Silent Aircraft Program (Programa "Aeronave Silenciosa) is an initiative of six Brazilian Universities and Institutes (USP-Poli "University of Sao Paulo - Polytechnic School, USP/EESC - University of Sao Paulo - Sao Carlos Engineering School, UFSC - Federal University of Santa Catarina, UFU - Federal University of Uberlandia, UnB - University of Brasilia and IAE - Brazilian Institute of Aeronautics and Space) together with Embraer to develop methodologies and solutions for the aircraft external noise problem. The main goal of this initiative is to study and develop methodologies that will allow estimation of aircraft noise generation and propagation through three main approaches: numerical simulation (CAA), analytical and semi-empirical models, and wind tunnel and flight tests.