Design of a Variable Stability System for the Cessna Citation II Fly-by-Wire Aircraft

A Variable Stability (VS) aircraft allows variations of response characteristics and Handling Quality (HQ) of an aircraft. By allowing for changing aircraft characteristics, the VS system has a diverse range of applications which include aircraft development, research of HQs, system tests and pilot training. This research investigates whether the Cessna Citations II, for its longitudinal dynamics, can be converted into a VS platform using a response feedback system.The research is focused towards obtaining a range of HQs of the aircraft using VS. The CAP criterion was used to evaluate these HQs. To assess the practicality of the VS system experiments were performed on a fixed-base aircraft simulator to investigate whether pilots experience a difference in HQs caused by the VS system and if the HQs, found analytically from computer-based simulations, match those found practically from the pilot tests.Results of the experiment show that pilots are able to identify the changes in aircraft dynamics and HQs caused by the VS system. For variations in HQs close to inherent Citation dynamics pilots ratings agreed with analytical results. However, for larger variations in HQs the pilots did not always agree with the HQs found analytically using the CAP criterionAerospace Engineerin