MEMS Package in a Harsh Environment for Aeronautic Applications

In special helicopter flight situations the main rotor blades frequently generate impulsive noise signatures resulting from the interaction of turbulence vortices and rotor blades. This happens e.g. often during descent helicopter flight situations where the blades also descent together with the helicopter and hit the downwashed vortices from preceding blades. This process is commonly called Blade Vortex Interaction (BVI). It is characterized by high noise levels and structural vibrations that can be reduced with active control devices at the blade root or at each blade individually. In closed-loop state, these devices react to a measured BVI characteristic value which is identified and evaluated with an appropriate sensor.