Page 23 - Root Cause Failure Analysis

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ROOT CAUSE FAILURE

ANALYSIS METHODOLOGY

RCFA is a logical sequence of steps that leads the investigator through the process of
isolating the facts surrounding an event or failure. Once the problem has been fully
defined, the analysis systematically determines the best course of action that will resolve
the event and assure that it is not repeated. Because of the cost associated with perform-
ing such an analysis, care should be exercised before an investigation is undertaken.

The first step in this process is obtaining a clear definition of the potential problem or
event. The logic tree illustrated in Figure 3-1 should be followed for the initial phase
of the evaluation.

REPORTING AN INCIDENT OR PROBLEM
The investigator seldom is present when an incident or problem occurs. Therefore, the
first step is the initial notification that an incident or problem has taken place. Typi-
cally, this report will be verbal, a brief written note, or a notation in the production log
book. In most cases, the communication will not contain a complete description of the
problem. Rather, it will be a very brief description of the perceived symptoms
observed by the person reporting the problem.

Symptoms and Boundaries
The most effective means of problem or event definition is to determine its real symp-
toms and establish limits that bound the event. At this stage of the investigation, the task
can be accomplished by an interview with the person who first observed the problem.

Perceived Causes of Problem
At this point, each person interviewed will have a definite opinion about the incident, and
will have his or her description of the event and an absolute reason for the occurrence. In

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