Noise Levels and Data Analyses for Small Prop-Driven Aircraft
FEDERAL AVIATION ADMINISTRATION WASHINGTON DC OFFICE OF ENVIRONMENT AND ENERGY
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During the Summer and Fall of 1982, the FAA Office of Environment and Energy, Noise Abatement Division, conducted a noise measurement program to evaluate proposed revisions of International and U.S. noise certification standards for light-weight propeller-driven aircraft. Tests were conducted using both single- and twin-engine propeller-driven light aircraft. Normally aspirated, turbo-charged, and turboprop engines were included, as were both fixed and variable pitch propellers. Takeoff noise measurements were made for eighteen aircraft. Additional measurements for nine of these aircraft during level flight provided sufficient data to examine the relationship of noise level versus helical tip Mach Number and engine power setting. This report presents noise measurements, aircraft position data, meteorological data, and cockpit instrument readings acquired during the test. Data analyses include corrections to proposed noise certification reference conditions, development of Mach Number and Power Correction functions, empirical examination of sound propagation, regression of noise level versus weight and the logarithm of weight and correlation of acoustical intensity AL and acoustical dose SEL noise metrics. While this report concludes that a takeoff noise certification procedure is feasible and will provide consistent results for a given aircraft, it remains uncertain whether or not equal stringency or even comparable stringency can be achieved between the existing certification procedure and the proposed takeoff procedure.
- Test Facilities, Equipment and Methods