A proposal for a Fully Distributed Flight Control System design

Since the delivery of the first A320 airliner with a Fly-by-Wire Flight Control System (FCS) in 1988, aircraft avionics architecture evolved significantly. Federated Architecture applied in the A320 family of aircraft presumed one computer per function. Limits regarding weight and space availability were reached and new generation of aircraft designed in early 2000s were equipped with Distributed Integrated Modular Avionics Architecture consisting of shared hardware resources running separate software modules according to aircraft priorities. Flight Control Computer functions were assumed by the Flight Control Module. While reducing the cost, weight and number of computers on board the aircraft, problems with troubleshooting and system modifications emerged. Proving that critical Systems perform within certain certification safety requirements became infeasible due to unpredictable dependencies between software modules. Abovementioned problems are addressed in this paper with a proposal of a Fully Distributed Flight Control System (FDFCS) design. Main contribution is that aircraft stability and trajectory control logic is distributed to a network of independent Control Units (CU) collocated on actuators collaborating to control the aircraft with respect to common goal. This paper outlines design for FDFCS and its CUs. Problems that distributed FCS implies and solves are identified. Finally, requirements for planned FDFCS Hardware in the Loop Simulator are set.