Architecture Considerations for Digital Automatic Flight Control Systems

Functional partitioning, redundancy structure, internal communications, and software modularization define the architecture of a digital automatic flight control system (DAFCS). Selection of a suitable system architecture for commercial transports involves such factors as the functional scope, growth provision and flexibility requirements, sensor interfaces, the aircraft´s actuator and control surface redundancy, and the dispatch reliability requirements. Trade-offs concerning these various factors are discussed, and it is shown that a very versatile and almost universal DAFCS can be configured to meet the general and peculiar needs associated with each aircraft application. Specific results associated with this system´s recent demonstration flights in the DC-10 aircraft, as well as examples from several other transport aircraft applications of the same DAFCS architecture, are used to illustrate the design concepts.