Anticipatory Failure Determination (AFD) is a failure analysis method.
Like FMEA, it has the objective of identifying and mitigating failures. Rather than asking
developers to look for a cause of a failure mode, it reverses the problem by asking
developers to view the failure of interest as the intended consequence and try to devise
ways to assure that the failure always happens reliably.
AFD offers an advantage over FMEA for more complex failure analysis in the following way.
FMEA relies on failures and their root causes being identified by the application of personal
experience or known (documented or applied) knowledge of others. However, the "denial
phenomenon" comes into play with this analysis. When we ask "what can go wrong" with respect
to a functioning system, we resist thinking about unpleasant possibilities that might occur
unless we have actually experienced them and they become real. Even when problems have been
experienced, people are reluctant to identify or document those problems. By reversing the
problem, AFD overcomes the "denial phenomenon" and opens up creative insights into analysis
AFD involves the following steps in its process:
- Formulate or invert the problem. Rather than guessing at possible causes of the
failure (how did it happen?), invert the problem to state how to make it
happen. Formulate a problem statement by stating the problem in
the following way: It is necessary to always produce the failure mode of
interest under the conditions that cause the failure. Begin with
identifying the conditions leading to the failure. Identify the
scenario or events involved in the failure and localize the failure.
- Search for solutions or methods to produce the
failure. Now that the problem has been changed from
possible things that can happen to things that need to be produced or
happen consistently, the thought process shifts to a inventive
method of finding the mechanisms or means of production. Function
analysis can be useful to identify a series of functions or actions
involved in the failure scenario. This helps to understand the
problem as well as help formulate the failure mechanism. By inverting
the problem, it is shifted to an issue of invention - how can something
be done or how can something be made to occur. TRIZ is a useful
technique to identify inventive approaches to making the failure
happen. This step should lead to identifying all of the standard
ways of creating the failure.
- Verify that resources are available to cause the
failures. There are seven potential categories of
resources: substances, field effects, space available, time, object
structure, system functions, and other data on the system. For
each of the potential solutions, identify if the required resources are
available to support the solution (failure).
Case studies to illustrate AFD can be found at:
- Inventive Troubleshooting -
Premature Artillery Shell Explosion (do an article search
within the site by title: Inventive Troubleshooting)
AFD Applied to an Engine Concern - Slow Oscillation