In the quest for the reduction of noise pollution, novel hybrid-electric or fully-electric power-trains promise to provide a substantial contribution. Especially closer to airfields, where acceptability issues tend to limit air operations with conventional fuel-burning engines, such novel power-trains allow to fly terminal maneuvers with a dramatically reduced impact on pollution. Considering the General Aviation (GA) field, where such new types of propulsion are more likely to gain a significant market share thanks to their favorable characteristics for this weight category, the reduction of the noise impact on ground may increase the infrastructural value of smaller airfields, often located in densely populated areas. This in turn would help in making novel power-train technologies economically advantageous at a system level. Despite these evident advantages, a methodology to quantify noise emissions of a novel type of power-train has not been identified yet – a fundamental step towards the assessment of the potential contribution of hybrid-electric or fully-electric aircraft to the global scenario of future aviation. This work introduces and discusses a possible procedure to provide such estimation. While mainly focused on the field of propeller-driven GA aircraft, the procedure presented herein can be easily scaled to cope with the specific features of heavier categories.

In order to quantitatively evaluate the advantages, in terms of noise emissions, of the application of modern electric power-trains to airplanes, an acoustic pollution prediction model was developed. The method mixes the benefits of best-practice and physics-based noise prediction procedures and is applicable to pure-electric and serial hybrid-electric General Aviation aircraft. Numerical results corresponding to circuit patterns in the vicinity of the Milan-Bresso airport are shown, proving the significant noise reduction that flying in pure-or partially-electric mode can bring for light aircraft operating around densely populated areas.