fault tree analysis

**Fault tree analysis (FTA)** is a **deductive technique starting from hazards** — working backward through logic gates (AND, OR) to identify component failure combinations that could cause system-level failures or hazards. **What Is FTA?** - **Definition**: Top-down analysis from hazard to root causes. - **Structure**: Tree with top event (hazard) and logic gates connecting to basic events (component failures). - **Purpose**: Identify failure combinations, assess safety, prioritize mitigation. **Logic Gates**: AND (all inputs must occur), OR (any input causes output), NOT, XOR, voting gates. **Key Concepts**: Minimal cut sets (smallest failure combinations), common cause failures, single-point failures. **Analysis**: Calculate top event probability, identify critical paths, find minimal cut sets, prioritize mitigation. **Applications**: Safety certification, hazard analysis, design review, maintenance planning, risk assessment. **Benefits**: Systematic hazard analysis, quantitative risk assessment, identifies critical components, supports safety cases. FTA is **detective work** reliability engineers perform to prevent system-level disasters through systematic failure analysis.