Design and Development of Aircraft Systems, 3rd Edition

5System Architectures

5.1 Introduction

The system architecture is an important tool in the design and development engineering process. It can form a part of the early visualisation of the concept stage by enabling requirements to be mapped at the top level onto elementary building blocks. Block diagrams are frequently used as ‘scribbling pads’ to play around with ideas of functions and data flows, as well as functional dependencies. A firm architecture can then be developed to add more detail, to incorporate functional to physical mapping, and to agree on functional allocations. This is a suitable stage to make decisions on which functions are to be put out to tender to suppliers.

The architecture is also a useful tool for ‘fixing’ external constraints. For example, a decision to use a particular commercial avionic standard, such as ARINC 429, will automatically determine some architectural principles, and the same is true of other data bus types. Other design drivers may include a decision to use of commercial off‐the‐shelf (COTS) components or customer inventory items that will similarly constrain the design. These restrictions can be recorded on the architecture diagrams and notes.

The system architecture is a representation of the conceptual shape and form of a system which can be visualised quite independently of any physical implementation. It is an invaluable device for making a simple and easy to understand representation of a system using a block diagram format as ...