By John Ager, Kepner Tregoe Inc.
“An Engineer’s Eureka Moment With a G.M. Flaw” By BILL VLASIC from the New York Times of MARCH 28, 2014 illustrates the importance of using Clear Thinking to manage knowledge and experience when troubleshooting. Mark Hood, “a veteran investigator of the engineering of airplanes, cars, trains and medical devices” had been hired in a lawsuit against General Motors over a fatal accident when the engine in the victim’s Cobalt had suddenly shut off.
When pursuing continuous improvement, there is rarely one right answer to the question; what should change to improve performance? Because of this, we should be open to creative solutions; new and different ways of doing things. Some refer to this as thinking outside the box. In reality, there is always a box, or frame, that limits our considerations; the chosen solution should maximize the results we value, minimize the resources we allocate, and satisfy the restrictions that bound us. But, the bigger you set your box, or frame, the more different are the solutions you can consider and the more likely you are to discover something truly original that provides tremendous value.
However, when troubleshooting, we need an accurate, rather than a creative answer to the question; what did change to diminish performance? We are looking for a definitive explanation and because there is a right answer, we need to focus our knowledge and experience and only apply those elements that are relevant to the problem at hand. So, unlike continuous improvement, when troubleshooting, the smaller our box the better. We want to look at things that are more similar rather than more different.
Data taken from the black box of the Cobalt indicated ignition failure as the cause of the engine shutting off. But how? Mr. Hood’s initial efforts, including photographing, X-raying, disassembling, and hours of testing the ignition switch from the Cobalt yielded no results. Although he had narrowed the search for cause to the ignition switch, there were still too many possible answers. His box was too big.
To make his box smaller, Mr. Hood bought a $30 replacement switch from a G.M. dealership. When he removed the original switch out of the ignition assembly from the salvaged car, and replaced it with the store-bought part, he realized the entire part now worked much better. Comparison of the two assemblies revealed significant differences: A tiny metal plunger in the switch was longer in the replacement part; the new switch’s spring was more compressed; and the force needed to turn the ignition on and off was greater. Vlasic writes, “the supplier that made the part, Delphi, had quietly changed the switch sometime in 2006 or early 2007, making it less likely that an unsuspecting driver could bump the ignition key and cause the car to cut off engine power and deactivate its air bags.”
So, the key to finding the cause of deviations is to make your box as small as possible to focus your knowledge and experience. The most effective way to make your box smaller is to compare the item in question with something that is as similar and closely related as possible. Although we are not looking for a creative answer, creativity can help us in our search—within the box--for data that leads to a definitive answer.
KT has a powerful toolkit for root cause analysis and preventing future problems