The Reverse Bell Curve

You have probably heard of a bell curve. Bell curves are typically used to show normal distribution. For example, intelligence in a given group can be graphed on a chart. Some people are lower than average, the majority are average, and some people are card-holding members of Mensa. The graph would look like a bell.

Did you realize that there is a reverse bell curve when it comes to aircraft maintenance? The left side of the chart would be maintenance errors and the bottom would represent number of years working as a mechanic. This bell curve would look like an upside down bell. 

When we start off as new mechanics, our tendency to make errors is high. As we gain experience, our skills improve and our knowledge of the aircraft systems increases dramatically. As a result, the tendency to make errors becomes much lower.

But something odd happens as we become more experienced. Our tendency to make errors goes back up. 

So, why wouldn’t the number or errors continue to decrease as we gain more and more experience? 

You can blame human factors. This tendency to make more errors is the result of letting complacency creep in. It’s the, “I’ve done that task so many times I could do it blindfolded!” mentality. We don’t bother referencing the maintenance manual before each task. We fail to follow work instructions, but instead perform the job and then fill out the boxes in the work instruction after we are done. For some, it goes even farther when they choose to not follow written procedures at all.

So, what can be done to help reduce the errors in the beginning and end of our career? 

New mechanics should be extremely diligent. Just because we have a brand spanking new mechanics certificate with an airframe and powerplant rating on it doesn’t mean we are ready to hit the hangar floor running. We need to take our time and listen to the advice of others. The hangar is no place for an ego. If we’re lucky, we will have a good mentor that will show us how to do things the right way. 

And what about us older mechanics? Well, we can’t allow ourselves to get complacent. In addition to fighting complacency, we are fighting father time. We must realize that as we get older, our physical limitations will make certain job tasks more difficult. Our deteriorating vision will make it more difficult to find defects. But hopefully the wisdom and knowledge we have gained over the years will help keep us on track!

In the end, our mentality should be to never stop learning. The day we decide we know it all is the day we should get out of aviation maintenance!

Thanks for reading, and we appreciate your feedback!


About D.O.M. Magazine

D.O.M. magazine is the premier magazine for aviation maintenance management professionals. Its management-focused editorial provides information maintenance managers need and want including business best practices, professional development, regulatory, quality management, legal issues and more. The digital version of D.O.M. magazine is available for free on all devices (iOS, Android, and Amazon Kindle).

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