Causal Control Flow Diagrams

In Reverse Engineering Examples the second example provides very-high-level Causal Control Flow Diagrams (CCFDs) for the fuel system of the Boeing 777 aircraft. The CCFDs show that, although the fuel system is conceptually quite simple for such an aircraft, the causal connections are in fact cognitively quite complex. This illustrates what we have often experienced with such analyses, that the operation of a system appears deceptively more simple than in fact it is. Which of course is why we advocate and use CCFDs.