Propeller aircraft noise legislation—A comprehensive review

Abstract After a brief historical review of the development of propeller aircraft noise certification by the International Civil Aviation Organization (ICAO), this paper describes in detail the pertinent ICAO-document—the ‘ANNEX 16’—which contains ‘Standards and Recommended Practices’ for the noise certification of propeller-driven aeorplanes either above, or not exceeding, a certificated take-off mass of 5700 kg. Direct experience in the ‘day to day’ practice of conducting aircraft flyover noise measurements for purposes of noise certification is revealed, potential pit-falls, ‘loop-holes’, and present uncertainties in the various procedures are described, and the efforts of the ICAO-Committee on Aircraft Noise (CAN), and its successor organization, the ICAO-Committee on Aviation Environmental Protection (CAEP) to resolve ensuing problems, are given extensive space. The continuing development, as well as the frequently necessary consolidations, of noise certification methods and procedures requires substantial research effort, both in terms of actual dedicated flight testing and wind tunnel testing. This work is dealt with in fair detail and where necessary explained with illustrations, often directly out of research reports. This should give the reader an impression of the enormous complexity of noise certificating propeller aircraft, which after all entails not only legislative aspects, but also basic and applied aerocoustic research. However, in addition to discussing the current state of propeller-aeroplane noise certification, there are sections which go back in time to elaborate on the thoughts and the sometimes dead-end streets which were penetrated in the numerous attempts to improve noise certification. Other sections still look into the future to present changes in propeller aircraft noise legislation that are expected to be agreed upon either in the near- or medium-term.