NEWSLETTERAristotel • April 23rd, 2012
Fixed and rotary wing pilots alike are familiar with potential instabilities or with annoying limit cycle oscillations that arise from the effort of controlling aircraft with high response actuation systems. These inadvertent undesirable aircraft or rotorcraft instabilities are the so- called Aircraft/Rotorcraft Pilot Couplings (A/RPC) because they originate from adverse pilot-vehicle couplings. These undesirable couplings can range in severity from benign to catastrophic; benign A/RPCs affect the vehicle's operational effectiveness; catastrophic A/RPCs result in the loss of the aircraft and lives. Until 1995, A/RPCs were usually known under the name of Pilot Induced/Pilot Assisted oscillations or Pilot in-the loop/Pilot-out-of-the-loop oscillations (PIO/PAO). The
