Human Error And Maintenance

Klaus M. Blache | March 6, 2024

Reducing industrial maintenance errors requires understanding and reducing human error in general, while improving human factors/ergonomics.

Human error has been studied by many in various fields and is often identified as the main cause of serious individual accidents, large disasters, and many small failures that are not always immediately evident.

Maintenance errors in industry have been shown to be 10% to 20% of total failures and accidents. The challenge is understanding and reducing human error in general, while improving human factors/ergonomics. Most practitioners relate ergonomics to the physical aspects of work and human factors to broader areas, including safety, reliability, decision making, and perception.

James Reason’s “12 Principles of Error Management” ( were written for aviation operations but have meaning in all industries. Below are the principles, followed by my comments of relevance:

1. Human error is both universal and inevitable. Error can be reduced, but not eliminated. The goal should always be to first “design out” potential issues. Then apply the concepts of design-for-maintainability to minimize risk.

2. Errors are not intrinsically bad. Errors will happen. It’s what you do next that matters. As Mark Twain said, “good judgment is the result of experience and experience is the result of bad judgment.”

3. You cannot change the human condition, but you can change the conditions in which humans work.  Human variability is huge, making it difficult to manage. But you can control the work processes, error proofing, and other risk mitigation to minimize consequences.

4. The best people can make the worst mistakes. Anybody can make a mistake. Having more knowledge and greater job scope can lead to bigger issues.

5. People cannot easily avoid those actions they did not intend to commit. Focus on process causes for errors/failures. People should, however, be required to follow the standardized best practices and always be engaged in continuous improvement.

6. Errors are consequences, not causes. Use root-cause analysis to investigate beyond symptoms to see what actually/physically happened and the impact human factors, processes, and dysfunctional/hidden issues had on the event.

7. Many errors fall into recurrent patterns. Use analytics to identify and mitigate/remove repeat errors.

8. Safety-significant errors can occur at all levels of the system. Error reduction is a system-level issue, from the plant floor to the plant manager.

9. Error management is about managing the manageable. It’s more difficult to control human variability/situational responses, such as decision making, than processes and technologies.

10. Error management is about making good people excellent. Since the exact error varies, it’s equally important to prepare for alternative situations and reactions.

11. There is no one best way. Be flexible toward accepting local variation regarding solutions that work. This also increases workforce buy-in and engagement.

12. Effective error management aims at continuous reform, not local fixes. Fix the process, not just the single event. Error reduction is a journey.

Because maintenance tasks can often have high variability and complexity, they are prone to performance variability and human error. EP

Based in Knoxville, Dr. Klaus M. Blache is director of the Reliability & Maintainability Center at the Univ. of Tennessee, and a research professor in the College of Engineering. Contact him at



Klaus M. Blache

Sign up for insights, trends, & developments in
  • Machinery Solutions
  • Maintenance & Reliability Solutions
  • Energy Efficiency
Return to top