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 of failures.
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