As we see, (because there are not natural crossing points between STO and PO) from the implementation point of view STO systems require different devices able to control compressors’ speed and airflow. Practically, there are 8-12 supplementary devices used to upgrade a standard PO system to a STO one. In addition, from this reasons, STO systems have not yet taken a strong development. Therefore, main effort do develop STO must be focused on crossing maneuver control.