The development of a European helicopter noise model

Abstract

No international consensus yet exists on a method for helicopter noise contour calculation for land-use planning. An intermediate approach is recommended in the Environmental Noise Directive (END) to model helicopters in a similar manner as fixed-wing aircraft. This method however, lacks the capability to capture the complex nature of helicopter noise adequately. The European Commission commissioned the development a helicopter noise model to be part of a public European environmental model suite for aviation. A helicopter noise calculation method was defined based on the current state-of-the-art, which was subsequently implemented in a software prototype (NORAH). Through dedicated flight test campaigns noise hemispheres were established for eight helicopter types, covering the noise relevant regions of the flight envelope. Based on these noise databases the noise emission of 70% of the helicopters flying in Europe can be represented in the NORAH model.