Autonomous and semi-autonomous aerial systems (AES) are often needed to perform tasks in complex and dynamic environments, especially in search and rescue applications. The safe navigation assurance as well as safety assurance of AES are open research issues. This paper investigates modeling of fall-back layer for AES assurance. To realize given advanced requirement the System Safety Surveillance and Control (SSSC) system concept is introduced. To fulfill safety requirements also for software developments formal requirements are formulated, to be realized with the formal modeling technique Strictly Formalized Situation-Operator-Modeling (sf-SOM). Fall-back system integration into AES can achieve system safety by separated safety consideration and emergency behavior integration and realization. Universally concept design permits the fall-back layer realization also for other applications. This in turn allows the first proof of concept of sf-SOM based SSSC system for fall-back layer realization using an experimental example. Here a Three-tank system is used to show the successful fall-back layer realization and the concept transferability to the introduced AES example.
