System Engineering Management, 5th Edition

Appendix A

Functional Analysis (Case-Study Examples)

A critical step in implementing the system engineering process is the accomplishment of the functional analysis and definition of the system in “functional” terms. Functions are initially identified as part of defining the need and the basic requirements for the system (refer to Figure 1.13, block 0.1). System operational requirements and the maintenance concept are defined, and the functional analysis is expanded to establish a functional baseline, from which resource requirements for the system are identified (i.e., equipment, software, facilities, people, data, the various elements of maintenance and support, etc.). The functional analysis is initiated during the conceptual design phase, and is described in detail in Chapter 2, Section 2.7.

Referring to the discussion in Section 2.7, accomplishment of the functional analysis can best be facilitated through the development of functional flow block diagrams (FFBDs), as illustrated in Figure 2.10. Such FFBDs are developed primarily for the purposes of structuring and transitioning system requirements into “functional” terms. The process for accomplishing such is covered in Section 2.1, and a few examples of FFBDs are presented in Figures 2.10 through 2.16. With the objective of further illustrating the development of these function flow block diagrams, Figures A.1 through A.6 are included to show a few simple applications:

1. Figure A.1 provides an example of the basic format ...