Functional Flow Analysis

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Functional Flow Analysis

• William W. Schoening
• Boeing - Aircraft and Missiles
• St. Louis, MO
• schoening_at_incose.org
• william.w.schoening_at_boeing.com

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Functional Flow Decomposition

• NUMBER ONE tool for systems engineers
• Understanding how products and services might be
  used

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How Products Might Be Used

• Key word is used -- not do
• Do tends to evoke current (and limited)
  functionality
• Successful products often have uses not
  anticipated by initial developers

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Functional Flow Decomposition

• NUMBER ONE tool for systems engineers
• Understanding how products and services might be
  used
• Discovering innovative solutions

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Innovation Via Reallocation
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There Is No Right Way
Balance major components of the system at the top
level functions
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Functional Flow Decomposition

• NUMBER ONE tool for systems engineers
• Understanding how products and services might be
  used
• Discovering innovative solutions
• Focusing attention away from what the product
  looks like (stop designing)

• Overcoming design road blocks

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Overcoming Design Roadblocks
Problem How to design a set of files used by
operations analysts to set up a simulation
The functional view changed the engineers view
of the problem
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Other Significant Benefits

• Explaining why your design makes sense
• Developing functional requirements
• Controlling the level of detail

And a Caution
Functional decomposition is a tool, and tools
have limitations
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• Functional decompositions are like voting in old
  time elections
• Use them early and often