What does the 'Swiss Cheese Model' illustrate in aviation safety?

The Swiss Cheese Model illustrates that accidents in aviation are typically the result of multiple systemic flaws aligning in such a way that they create a pathway to failure. Each layer of defense, represented by slices of cheese with holes, is designed to prevent accidents. However, the holes in these slices may not align perfectly, which means a potential accident can be prevented if flaws in different layers do not coincide. When these holes do align, it allows for the progression of an error to result in an accident. Thus, this model underscores the importance of maintaining defenses and identifying weaknesses across an entire system to enhance safety. Understanding this model is crucial in aviation safety practices as it emphasizes the need for a comprehensive approach to hazard identification and risk management, rather than attributing accidents to random chance or assigning undue importance to single factors like training alone.