The RCA

Much has been written about James Reason’s original Swiss Cheese Model described in his book Managing the Risks of Organizational Accidents. Figure 1 is a basic representation of this model. Many today consider this model to be obsolete because of the evolving complexity of systems due to emerging technologies. Therefore, the linearity of failure expressed in this original model, is not as applicable as it was when introduced.

When facilitating a Root Cause Analysis (RCA), the proper questioning process will make or break the effectiveness of the entire analysis. When we hear of the 5-Why’s as a valid RCA approach, is simply asking ‘Why?’ 5x good enough….or IS IT JUST OK?

Think about it this way, if I asked you ‘How Could’ the crime have occurred versus ‘Why’ the crime occurred, would your answers be different?

I am going to take a very basic (101) case study and format it using a logic tree (graphical expression of cause-and-effect logic). As we are guided through this mental process we will discuss the differences between asking ‘How Can?’ and ‘Why?’.

There is great variation when it comes to a common understanding of the term ‘Root Cause Analysis’ or RCA. 

In a previous, lengthy paper, I wrote an article entitled “The Stigma of RCA: What’s In a Name?“. It focused on common understandings (or misunderstandings) of what RCA means and then described the basic steps of any investigative occupation. I just left it up to the reader to determine if their ‘RCA’ approach had room for improvement. 

“Preventing process accidents requires vigilance. The passing of time without a process accident is not necessarily an indication that all is well and may contribute to a dangerous and growing sense of complacency. When people lose an appreciation of how their safety systems were intended to work, safety systems and controls can deteriorate, lessons can be forgotten, and hazards and deviations from safe operating procedures can be accepted.

I have been very involved recently with ongoing LI discussions with respected and noted experts in the Safety community, revolving around the perceptions those in Safety have of Reliability, and vice-versa.

In Safety today, there are ‘new’ approaches emerging being lead by noted Safety researchers like Sidney Dekker, Erik Hollnagel and Todd Conklin. Such ‘new’ approaches are being labeled Safety Differently, Safety II, Human and Organizational Performance (HOP), Resilience Engineering and a few more.

There has been an ongoing debate for decades as to whether or not the use of pre-existing logic for conducting Root Cause Analyses helps or hinders the analysis results. Does the use of such pre-existing logic expand the thinking of the team members or does it lead the team to pre-determined conclusions and away from other conclusions not considered in the pre-existing logic? We will explore the fine line between these opposing views and see if there is a middle ground for consensus. [Read more…]

This phrase ‘a little bit bold & outrageous’ was constantly used by my father, Charles J. Latino early in his Reliability career. Charles founded and led one of the first corporate, global Reliability Engineering R&D groups in the U.S. for a company called Allied Chemical at the time (known as Honeywell today). This was in 1972!

We often hear our organizations referring to their workforce as their greatest ‘asset’. But are they really?

Let’s first define ‘asset’ from a financial perspective:

“In financial accounting, an asset is an economic resource. Anything tangible or intangible that can be owned or controlled to produce value and that is held by a company to produce positive economic value is an asset. Simply stated, assets represent value of ownership that can be converted into cash (although cash itself is also considered an asset)”

If you had to give a grade to your current Root Cause Analysis (RCA) initiative, what would it be? How would you come to that conclusion (grade)? The paradox many face with such initiatives is drawing the distinction between compliance and actual effectiveness. What would our RCA grade be based on? In this article we will focus on the key elements to quantifiably measure your RCA initiative, so the organization can focus on the elements of the initiative that are lacking.

In this original post, A Mechanic’s Story: Basic Component Fatigue, we took a detailed journey through the physical side of a shaft failure RCA. We stopped at the physical side of that failure, parallel misalignment. However, stopping at the component level of failure does not constitute a credible and thorough RCA. Actually stopping at this level is more along the lines of a Shallow Cause Analysis (SCA). So let’s explore what makes the difference between a Shallow Cause Analysis and a Root Cause Analysis (RCA).

In the previous post we stopped at parallel misalignment. We will continue drilling from that point down. We ask ‘How could we have had parallel misalignment?’ Our team of subject matter experts (SME) hypothesizes 1) it was either misalignment at installation or 2) it became misaligned during operations. 

As many of you know, I have been encouraging my LI contacts for years to take me up on my offer to review any pictures they have of failed parts, and we would try and provide them some preliminary feedback. Well, someone finally took us op on the offer and we wanted to share what was learned (we obtained permission to do so providing the company name was not used).

Here was the original inquiry via LI instant messenger along with the pictures:

“Dear Sir, As per your advise, I’m sending you a photo of failed flange bolts. I belief they were failed due to fatigue. Could you please review them and identify/ label their failure mode. After your comments on this photo, I’ll put up a recommendation on my RCA. Looking forward to hear from you. Regards.”

“Assumption 1: Safety is increased by increasing system or component reliability. If components or systems do not fail, then accidents will not occur. (p. 7)

This assumption is one of the most pervasive in engineering and other fields. The problem is that it is not true.

Safety is a system property, not a component property, and must be controlled at the system level, not the component level. 

New Assumption 1: High reliability is neither necessary nor sufficient for safety. (p.13)”

These statements were excerpted from Nancy Leveson’s “Engineering a Safer World“. 

This contradicts the common belief there is a direct correlation between Safety and Reliability. I personally, being in the Reliability field for 30+ years, believe there is a correlation between Reliability and Safety. But I would assert that it is not a direct correlation. 

In past articles, we have explored the basics of Erosion, Corrosion, Fatigue and Overload. Our emphasis has been on creating an awareness and appreciation for the value of failed components, to any investigation.

In this article we are going to delve into Fatigue a little bit more (because it is the most common fracture pattern) and see how we can use an evidence-based, deductive logic process to determine what elements of Fatigue may have been at play. We are trying to create an intellectual curiosity within the front lines about ‘making the call’…is it Fatigue, or some other fracture pattern?

I recently received an interesting LI inquiry that I felt others could learn from the answers that I was able to get. This is not my expertise so I sought out answers from some colleagues who were more familiar with fasteners.

Here is the original inquiry (translated from Portuguese so I hope Google Translator did a good job):

“I would like to know if you can help me clarify my doubts about:

1. The purpose of conducting a study of the coefficients of friction in screws, threads and nuts?
2. Is there an accurate standard for such testing?
3. What methods can be perfected in projects that target this type of trial and application?
4. Can surface treatments influence changes in results?
5. Who is responsible for such testing (the manufacturers and suppliers of raw materials, the assembler and/or its various final assembly applications)?