Ingeniero

A PRACTICAL GUIDELINE FOR A SUCCESSFUL ROOT CAUSE FAILURE ANALYSIS
by
David L. Ransom
Senior Research Engineer
Mechanical and Materials Engineering Division
Southwest Research Institute
San Antonio, Texas

they also represent organizational inability to successfully manage
the competing interests of time, quality, and money. Therefore, in
the interest of continuous improvement, it is inone’s best interest
to learn all one can from these failures, allowing us to avoid
making the same mistake twice.
The objective of this tutorial is to provide the reader with a
practical guide for performing root cause failure analysis and
determining the appropriate corrective/preventive action necessary
to avoid the same failure in the future. The root cause failure
analysis (RCFA)process begins with the collection phase, followed
by the analysis phase, and concludes with the solution phase. Each
of these phases is shown in Figure 1.

David L. Ransom is a Senior Research
Engineer at Southwest Research Institute,
in San Antonio, Texas. His professional
experience over the last 10 years includes
engineering and management responsibilities
at Boeing, Turbocare, andRocketdyne. His
research interests include rotordynamics,
structural dynamics, seals and bearings,
finite element analysis, and root cause
failure analysis. He has authored eight
technical papers in the field of rotordynamics and thermodynamics.
Mr. Ransom received his B.S. degree (Engineering Technology,
1995) and M.S. degree (Mechanical Engineering, 1997) from Texas
A&M University. He is also alicensed Professional Engineer in the
State of Texas.

ABSTRACT
Root cause failure analysis is a process for identifying the
true root cause of a particular failure and using that information to
set a course for corrective/preventive action. From a technical
standpoint, it is usually a multidisciplinary problem, typically
focused on the traditional engineering fields such as chemistry,physics, materials, statics, dynamics, fluids, etc. However, it seems
that too often the analysis stops with the technical aspects that are
easily understood in an engineering environment, where the real
root cause may exist in the human organization. In this tutorial, a
practical guide to root cause failure analysis will be provided,
followed by case studies to demonstrate both the technicaland
organizational nature of a typical root cause failure analysis.

INTRODUCTION
Despite the best efforts to avoid them, failures are still a
common occurrence in every industry. Of course, there are
the more obvious and well-publicized failures in the automotive,
petrochemical, aerospace, and mining industries, just to name a
few, but there are also many less catastrophic failuresoccurring at
any point in time. Failures not only represent imperfection in the
technical attempt to design and operate complicated systems, but

Figure 1. RCFA Flow Chart.
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PROCEEDINGS OF THE THIRTY-SIXTH TURBOMACHINERY SYMPOSIUM • 2007

Within collection, there are several key steps including team
forming, problem definition, and of course data collection. The
analysis phase issimply represented by determining the
immediate, contributing, and root causes of the defined problem.
The solution phase consists of determining corrective/preventive
action, and then testing and implementation, which of course is
the final step in RCFA. In each phase of the process, there are
critical steps and simple guidelines to consider that will keep the
investigation focused andpractical. There are also some practical
methods for organizing the investigation, depending on the size
of the system under review. Finally, two turbomachinery related
case studies are presented and discussed throughout the length
of the tutorial to assist in demonstrating the overall process
and guidelines.

questions or assist in the development of viable solutions. These
“expert” team...