Runtime Assurance (RTA) is becoming a trend in the aerospace and Unmanned Aerial Vehicle (UAV) industries due to its benefits, such as ensuring the safety of a safety-critical system, e.g., Urban Air Mobility, without a formal verification of the primary system controller. The principle of RTA revolves around the notion of maintaining a backup controller and executing it whenever the primary controller appears to harm the system. Additionally, a modern avionics architecture (distributed), consisting of nodes (sensors, actuators, computing units, etc.) capable of exchanging information via a reliable, standard communication network, can also benefit from RTA. Hence, integration of the RTA framework into an avionics architecture can allow for a reduced degree of verification for these algorithm and, in turn, promote autonomy levels of the avionics systems.This paper presents a formal RTA definition and framework for the distributed avionics architecture to obtain the benefits of resource sharing and improved system autonomy. We also demonstrate a real-time execution of RTA implementation on a multirotor vehicle equipped with distributed avionics architecture in the event of failure.