European researchers investigated safety issues concerning aeroplane and helicopter engines and the problems associated with High cycle fatigue (HCF), particularly in the turbine blades. The ADTURBII project applied a multidisciplinary approach which included the study of aerodynamics, structural mechanics and the behaviour of materials. The project's aim was to cut the number of incidents of HCF in half by achieving a better understanding of aero-elastic phenomena through a series of experiments. A team of scientists from Imperial College, London, investigated mistuning in rotors and the measures required to prevent it occurring. Mistuning results from a lack of symmetry in an object that needs to be completely symmetrical in order to function efficiently. In reality, however, disparities in manufacturing, ageing and the properties of materials mean that perfect symmetry is not achieved. The result is that individual blades move and vibrate differently, causing the mistune phenomenon, which amplifies the response of the turbine blades to mechanical and aerodynamic excitation. The goal of the Imperial College group was to minimise the rotor’s sensitivity to mistuning. In order to achieve this target the researchers carefully characterised the test conditions and used the results from their study to validate new methods of design. The benefits of the work undertaken include greater reliability of engines, reduced production costs and improved safety for passengers and crew.