Functional flow block diagram

A 1944 graduate of Mogensen's class, Art Spinanger, took the tools back to Procter and Gamble where he developed their Deliberate Methods Change Program.

[5] The modern Functional Flow Block Diagram was developed by TRW Incorporated, a defense-related business, in the 1950s.

[6] In the 1960s it was exploited by NASA to visualize the time sequence of events in space systems and flight missions.

FFBDs show the same tasks identified through functional decomposition and display them in their logical, sequential relationship.

For example, the entire flight mission of a spacecraft can be defined in a top level FFBD, as shown in Figure 2.

The FFBD also incorporates alternate and contingency operations, which improve the probability of mission success.

[9] A line with a single arrowhead shall depict functional flow from left to right, see Figure 4.

Figure 1: Functional flow block diagram format. [ 1 ]
Figure 2: Development of functional flow block diagrams [ 8 ]
Graphical explanation of a "function block" used in these diagrams. Flow is from left to right. [ 4 ]
Figure 3. Function symbol
Figure 4. Directed lines
Figure 5. "AND" symbol
Figure 6. "Exclusive OR" Symbol
Figure 7. "Inclusive OR" logic
Figure 8. FFBD Function 0 illustration
Figure 9. FFBD Function 2 illustration