2. Maintenance, risk and performance

Functional safety, as defined above, is usually perceived as a "range of methods and concepts designed to control risks" [AG 4 670] . However, while some characteristics are indeed "anti-risk" (safety, security, environmental harmlessness), others (availability, cost control, product and service quality) are properties designed to ensure performance. In what follows, we will try to situate maintenance in relation to these two aspects: risk and performance.