ADVANCED SYSTEM CONCEPTS FOR FUTURE CIVIL AIRCRAFT - AN OVERVIEW OF AVIONIC ARCHITECTURES

The avionics systems of state-of-the-art commercial aircraft have beco me increasingly complex and sophisticated, in order to meet the ever i ncreasing performance and reliability requirements. With the capabilit y of the avionics technology improving by an order of magnitude every few years, it is envisaged that the current philosophy of one box-per- function will soon reach its limits in terms of cost, functionality, r eliability, and certification. The proposed solution is the integrated systems configuration, using distributed processing, where the comput ational resources are shared between many functions, therefore improvi ng the reliability, availability, survivability, and extensibility of the overall system. Futhermore, this approach will also provide the po tential for reducing the acquisition, maintenance and operating costs. The paper discusses the limitations of the current avionic system's a rchitecture in dealing with the high levels of functionality required by the state-of-the-art aircraft, and discusses the philosophy of the integrated modular avionics, which represents a change in philosophy o f avionics design to a decentralized, distributed architecture that al lows interchangeable components within a distributed aircraft avionic system. The paper also addresses a number of specific issues considere d necessary for the implementation of a decentralized, distributed arc hitecture such as data bus requirements, electromagnetic and radio fre quency prevention, and fault tolerance. But it also argues that for tr ue systems integration, a new culture is required based on open system s with a set of inherent quality features such as conformance, robustn ess, extendibility, compatibility, and reusability built into the arch itecture.