Noise Measurement Flight Test: Data/Analyses Aerospatiale AS 350D AStar Helicopter

This report documents the results of a Federal Aviation Administration FAA noise measurement flight test program with the AStar helicopter. The report contains documentary sections describing the acoustical characteristics of the subject helicopter and provides analyses and discussions addressing topics ranging from acoustical propagation to environmental impact of helicopter noise. This program was designed to address a series of objectives including 1 acquisition of acoustical data for use in assessing heliport environmental impact, 2 documentation of directivity characteristics for static operation of helicopters, 3 establishment of ground-to-ground and air- to-ground acoustical propagation relationships for helicopters, 4 determination of noise event duration influences on energy dose acoustical metrics, 5 examination of the differences between noise measured by a surface mounted microphone and a microphone mounted at a height of four feet 1.2 meters, and 6 documentation of noise levels acquired using international helicopter noise certification test procedures.