fault-tree-builder

What problem does it solve?

This Skill eliminates the risk of non-compliant, incomplete fault tree analysis for safety-critical systems, which is a mandatory requirement for regulatory certifications including ISO 26262 ASIL D, IEC 61508 SIL 3, and RTCA DO-178C Level A. Manual fault tree construction often misses minimal cut sets, fails to document independence assumptions, or produces inconsistent probability values that invalidate safety claims.

Core Features & Use Cases

• Top-down deductive tree construction: Build fault trees from undesired top events using AND, OR, voting, and inhibit gates per IEC 61025, with documented independence arguments for all AND gates.
• Minimal cut set extraction: Automatically identify single points of failure and high-risk failure combinations to prioritize redundancy and mitigation efforts.
• Quantitative safety validation: Roll up basic event probabilities to calculate top event probability and validate against tolerable hazard rate thresholds from safety goals.
• Cross-artifact consistency checks: Reuse failure-in-time values from linked FMEDA artifacts and align basic events with threat model findings to avoid conflicting safety data.
• Use Case: For an automotive brake control system targeting ASIL D, use this Skill to build a fault tree for the "uncontrolled brake release" top event, extract minimal cut sets, and confirm the top event probability meets the safety goal's 1e-8 per hour tolerable hazard rate.

Quick Start

Use the fault-tree-builder skill to construct a fault tree for the undesired top event "uncontrolled brake release" from the system architecture and linked ASIL D safety goal, then extract minimal cut sets and validate the top event probability against the tolerable hazard rate.