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.