Validation Testing for Flutter Certification of the New High-Performance Trainer Aircraft PC-21

Abstract

The new trainer aircraft PC-21 is presently under development by the Swiss company Pilatus Aircraft Ltd.. To fulfil the flutter certification requirements, comprehensive analytical and experimental investigations had to be performed. For the flutter analysis a reliable mathematical finite element model of the aircraft was required to describe the structural dynamics behaviour including the complete control system. In order to validate the finite element model, ground vibration tests including dedicated non-linearity tests were performed on the PC-21 prototype. The ground vibration test provided a reliable data base for updating and refinement of the mathematical model. Flutter calculations were performed using both the measured modes and the analytical modes. The results of the flutter analysis are compared with the flight test results of the aircraft. The present paper gives a survey on the complete flutter certification process within the development of a new modern aircraft. This includes the necessary activity steps from mathematical modelling, experimental verification, flutter analysis up to flight testing. The importance of dedicated validation testing within this process is emphasised.