Helicopter Noise Abatement Arrival Trajectories

A computational platform is presented that aims to optimize helicopter trajectories with respect to the noise impact in near-heliport communities under varying atmospheric conditions. The software suite is based on a fast gradient-based optimization algorithm which is linked to a rigid-body helicopter flight mechanics model to model the free motion of the helicopter. To optimize with respect to community noise impact, the suite contains three consecutive models. First, the source noise levels are determined using an extensive hemispherical database determined based on an aeroacoustic-elastic formulation of the main rotor. Next, the propagation losses are determined using a ray-tracing approach which can account for different atmospheric conditions and ground surfaces, to find the noise levels in the observer locations. Finally, the suite contains accurate population density data and various noise impact assessment criteria to determine the aggregated noise impact. As an example of the capabilities of the newly developed tool a VFR approach procedure at Amsterdam Airport Schiphol has been optimized for different noise criteria and for different wind conditions.