3. Understanding and controlling deviations from required behaviour

Contextual description: Even if sufficient effort is made to implement a system that satisfies all the safety requirements, it is still necessary to also explicitly consider the ways in which the system may deviate from that required behaviour during operation. Deviations may arise due to random failures (such as component degradation during operation) or systematic failures (such as design errors) in the system. To provide assurance, the potential for unsafe deviations must be identified and mitigated as considered in the following sub-objectives described below.

Practical guidance: 

Next sections:

• 3.1 Identification of potential deviation from required behaviour (guidance available)
• 3.2 Mitigating potential deviations (guidance available)