To handle the complexity in avionic systems, the application software are large and becoming hard to meet the real-time capabilities. The proposed architecture for avionics control system meets the requirements of fault tolerance as a major issue. Fault tolerance proposed in this paper is based on redundancy; permanent faults are covered by hardware replication, transient faults, and fault detection which are processed by software techniques. In this paper, we propose the architecture which is flexible on distributed function and assured replication that can react to failures on real time in both hardware and software of UAV (unmanned aerial vehicle). This reliable architecture can enhance analysis capabilities for critical safety properties and reduce certification costs for such systems using hardware in loop simulation.