Interactive cockpits have been used since the early 00's in many aircraft cockpits, but the use of interactivity still remains limited to non-critical functions even in the most recent aircrafts. Indeed, engineering such interactive systems is still a challenge and their engineering has not reach the Design Assurance Level required for critical functions. In interactive cockpits, interaction takes place through graphical input devices and keyboards (such as the Keyboard Cursor Control Unit in Airbus family) while the behavior of the User Interface (UI) must be compliant with the specifications defined in ARINC 661 standard. The tool-supported three-fold approach presented in this paper proposes means for increasing the assurance level of interactive systems. The approach includes a formal description technique for describing each component of an interactive system (detection and prevention of development faults), a command and monitoring technique dedicated to interactive systems components (detection of natural faults) and a segregation runtime environment (prevention of faults propagation) We report on the implementation of a Flight Control Unit (FCU) panel using this approach, inspired by the FCU of the A380.