Title: Safety Analyses | ISO 26262 Academy URL: https://iso26262.academy/features/concepts/safety-analyses Description: Learn how HARA, FMEA, FTA, STPA, DFA, and HAZOP complement each other across the ISO 26262 lifecycle. --- Concept guide · ISO 26262-9 §8 · 14 chapters # Safety Analysis Framework Master the integrated safety analysis framework for ISO 26262 covering HARA, FMEA, FTA, DFA, STPA, Markov analysis, HAZOP, and event trees with guidance on method selection, sequencing, and evidence integration. 14 Chapters 8+ Analysis Methods STPA Modern Methods ETA Event Trees Included in Expert [Start learning](https://iso26262.academy/register?plan=free&from=%2Fconcepts%2Fsafety-analyses&utm_source=website&utm_medium=cta&utm_campaign=features_concepts) See the chapters Inside the course 1. 01 **Overview & Integration** 2. 02 **HARA Fundamentals** 3. 03 **FMEA Integration** 4. 04 **FTA Integration** 5. 05 **DFA - Dependent Failure Analysis** The short version ## Quick answers What are safety analyses in ISO 26262? Safety analyses are the systematic examinations required by ISO 26262-9 Clause 8 to identify the causes and effects of faults and to validate that safety requirements and mechanisms are adequate. The standard distinguishes inductive (bottom-up) methods such as FMEA, which start from failure modes and derive effects, and deductive (top-down) methods such as FTA, which start from an unwanted event and derive causes. Analyses can be qualitative or quantitative, and the rigor required scales with ASIL - higher integrity levels call for both directions of analysis. Their results feed safety concepts, hardware metrics, and ultimately the safety case. Which safety analysis method should I use, and when? Use the question you need answered. HARA identifies hazards and assigns ASILs at concept time. FMEA gives systematic bottom-up coverage of single failure modes at system, hardware, and software levels; FMEDA is its quantified hardware form. FTA finds combinations of failures behind one top event and quantifies their probability. DFA hunts common-cause and cascading failures that undermine independence claims. STPA finds unsafe control actions in complex, software-intensive control structures. Markov analysis handles state-dependent behavior like repairable redundancy. For ASIL C and D, ISO 26262 expects an inductive and a deductive analysis working together, not a single method. Keep going, free - [Demo exam · no account Test yourself with 7 exam-style questions](https://iso26262.academy/demo-exam) Why this course · ISO 26262, Part 9, Clause 8 ## Why it pays for itself ### Choose the right method HARA, FMEA, FTA, DFA, STPA, Markov, HAZOP, and event trees each answer a different question. Learn what each method finds, what it misses, and which combination your ASIL actually requires. ### Sequence analyses across the lifecycle See when each analysis runs, how HARA outputs feed FMEA and FTA, how results iterate with the architecture, and how everything integrates into one coherent safety case instead of disconnected worksheets. ### Cover the modern methods too Beyond the classic inductive and deductive pair, the course covers dependent failure analysis, STPA for control-structure hazards, Markov models for state-dependent systems, and event trees for consequence analysis. After the course ## What you’ll be able to do ### Select Appropriate Analysis Methods Choose the right safety analysis method for each objective using a structured selection framework based on system type, lifecycle phase, and analysis depth required. ### Execute Integrated FMEA & FTA Conduct complementary FMEA and FTA campaigns with consistent failure mode definitions, bidirectional result linkage, and combined PMHF contribution calculation. ### Conduct Dependent Failure Analysis Systematically examine independence assumptions in decomposed architectures and identify CCF vulnerabilities that could defeat redundant safety measures. ### Apply Modern Methods (STPA) Use STPA for systematic unsafe control action identification, complementing traditional FMEA/FTA with system-theoretic analysis for complex, software-intensive systems. ### Maintain Cross-Analysis Consistency Verify that safety analyses are mutually consistent, resolve contradictions between methods, and ensure complete hazard coverage across all analysis outputs. ### Integrate Analysis into Safety Cases Map safety analysis results to safety argument claims and structure analysis evidence packages that support a compelling and assessor-ready safety case. The curriculum · 14 chapters ## Chapter by chapter 1. 01 **Overview & Integration** Introduce the ISO 26262 safety analysis landscape, understand how different methods are complementary rather than competing, and learn how analysis results integrate into the safety case at each lifecycle phase. - Method landscape - Complementary analysis - Lifecycle integration 2. 02 **HARA Fundamentals** Review Hazard Analysis and Risk Assessment as the foundation analysis that drives all subsequent safety work. Focus on how HARA outputs feed FMEA, FTA, DFA, and the overall safety argument structure. - HARA outputs - Safety goal derivation - Downstream analysis feeds 3. 03 **FMEA Integration** Apply FMEA at system, hardware, and software levels within the ISO 26262 framework. Understand Design FMEA vs. Process FMEA, FMEDA as a specialized form, and how FMEA results support safety mechanism identification. - DFMEA vs. PFMEA - FMEDA as specialized FMEA - Safety mechanism linkage 4. 04 **FTA Integration** Apply Fault Tree Analysis for top-down probabilistic safety analysis in ISO 26262. Covers tree construction, gate types, minimal cut sets, quantitative analysis, and how FTA results contribute to PMHF calculation. - Tree construction - Minimal cut sets - PMHF contribution 5. 05 **DFA - Dependent Failure Analysis** Conduct Dependent Failure Analysis per ISO 26262 to identify failures that can invalidate independence assumptions in decomposed architectures. Covers analysis at item and element level with CCF and cascade failure identification. - Independence assumption testing - CCF identification - Cascade failure analysis 6. 06 **STPA Integration** Apply System-Theoretic Process Analysis (STPA) for systematic identification of unsafe control actions and loss scenarios. Understand how STPA complements traditional FMEA/FTA and supports SOTIF analysis alongside ISO 26262. - Unsafe control actions - Loss scenarios - ISO 26262 + SOTIF bridge 7. 07 **Markov Analysis** Apply Markov chain modeling for state-based reliability and safety analysis in complex systems with repair, partial operation, and degraded modes. Understand when Markov analysis is more appropriate than FTA for ISO 26262. - State-based modeling - Degraded mode analysis - Markov vs. FTA selection 8. 08 **HAZOP** Apply Hazard and Operability Study (HAZOP) to identify deviations from design intent in automotive E/E systems. Covers guide word selection, node definition, deviation analysis, and how HAZOP complements FMEA for system-level hazard identification. - Guide word method - Node definition - FMEA complement 9. 09 **Event Tree Analysis** Construct Event Tree Analysis (ETA) for analyzing sequences of events following an initiating event. Understand how ETA integrates with FTA, how safety system success probabilities are incorporated, and automotive ETA examples. - Event sequence modeling - FTA integration - Automotive examples 10. 10 **Method Selection Guide** Select the right safety analysis method for each situation using a structured decision framework based on system complexity, analysis objective, available data, and ISO 26262 applicability requirements. - Decision framework - Objective-method mapping - ISO 26262 requirements 11. 11 **Sequencing & Traceability** Plan the correct sequencing of safety analyses across the development lifecycle and maintain traceability between analysis outputs. Learn how HARA→FMEA→FTA→DFA feeds forward and how analysis results are revisited as design evolves. - Analysis sequencing - Forward/backward traceability - Design evolution 12. 12 **Consistency Checking** Verify consistency between different safety analyses covering the same system. Identify and resolve contradictions between FMEA and FTA results, ensure DFA findings are addressed in FMEA, and cross-check HARA hazard coverage. - Cross-analysis consistency - Contradiction resolution - HARA hazard coverage check 13. 13 **Evidence Integration** Integrate safety analysis results into the safety case evidence structure. Map analysis findings to safety argument claims, structure analysis reports for assessor review, and maintain analysis work products as living documents. - Safety case integration - Claim-evidence mapping - Living document management 14. 14 **Validation & Verification** Verify that safety analyses are complete, consistent, and correct. Apply review checklists for each analysis method, conduct cross-analysis validation, and prepare analysis evidence packages for Functional Safety Assessment. - Analysis review checklists - Cross-analysis validation - FSA preparation Interactive Tools ## Not just text: the visual toolkit ### Method Selection Matrix Interactive matrix for selecting safety analysis methods based on analysis objective, lifecycle phase, system type, and available evidence with pros/cons and applicability guidance. ### Analysis Sequencing Timeline Visual timeline showing the recommended sequencing of HARA, FMEA, FTA, DFA, and other analyses across the ISO 26262 V-Model phases with dependency arrows and update triggers. ### FTA Builder Interactive fault tree construction tool with AND/OR gate logic, minimal cut set calculation, probability propagation, and PMHF contribution visualization. ### DFA Independence Analyzer Tool for mapping independence assumptions from ASIL decomposition to DFA examination scope, identifying potential failure dependencies, and documenting CCF prevention measures. ### STPA Control Structure Diagram Interactive control structure diagram builder for STPA analysis with unsafe control action identification, causal factor analysis, and loss scenario enumeration. ### Cross-Analysis Consistency Map Visual consistency checking tool mapping failure modes across FMEA, FTA, and DFA analyses to identify gaps, contradictions, and unresolved findings between methods. Worked Examples ## Integrated Safety Analysis for ADAS Perception System Complete multi-method safety analysis for an ADAS forward-looking perception system at ASIL-B, combining HARA, FMEA, FTA, DFA, and STPA with cross-analysis consistency verification. - HARA analysis identifying 12 hazardous events with ASIL assignments for perception failures - System-level FMEA covering camera, radar, and fusion ECU failure modes - FTA for safety goal "No unintended activation of AEB" with PMHF calculation - DFA examining independence between camera and radar sensor paths - STPA analysis of the AEB control loop identifying 8 unsafe control actions - Cross-analysis consistency check and integrated evidence package assembly Perception System Safety Analysis Map HARA analysis - 12 hazardous events with S/E/C classification Unlock 5 more analysis methods Built for ## Who this guide is for - Safety engineers planning the analysis strategy for a new item or element - Analysts fluent in one method (usually FMEA) who need the full toolbox - Safety managers deciding which analyses to require from suppliers at each ASIL - Engineers integrating analysis results into a safety case for assessment ## Frequently Asked Questions Common questions about Safety Analysis Framework DFA examines whether elements assumed to be independent actually are. It targets two enemies of redundancy: common-cause failures, where one root cause - shared supply, clock, temperature, or a shared design flaw - takes out multiple elements at once, and cascading failures, where one element's failure propagates to another. DFA is what makes ASIL decomposition and freedom-from-interference claims credible: without it, a 1oo2 architecture or a decomposed requirement rests on an unproven independence assumption, which is exactly the kind of gap assessors probe. STPA (System-Theoretic Process Analysis) is not named in the ISO 26262 method tables, but the standard's analysis requirements are method-agnostic, and STPA is increasingly used alongside FMEA and FTA - especially for software-intensive and highly automated systems. Its value is a different failure model: instead of component faults, it looks for unsafe control actions in the control structure - commands given when they shouldn't be, missing when needed, or mistimed. That surfaces specification and interaction hazards that component-oriented methods structurally miss. The course positions it as a complement, not a replacement. The guide covers the integrated framework in 14 chapters, spanning more than 8 analysis methods: HARA, FMEA and FMEDA, FTA, DFA, STPA, Markov analysis, HAZOP, and event tree analysis, with guidance on method selection, sequencing across the lifecycle, and integrating the evidence into the safety case. A free account starts you off, and the Pro and Expert plans unlock more of the library. ## Start the course today A free account unlocks one full concept guide, 3 work product templates, 1 guided process, the Markov simulator, and 5 practice exams per month. The Pro and Expert plans unlock more of the 78-guide library. No credit card required. [Start learning](https://iso26262.academy/register?plan=free&from=%2Fconcepts%2Fsafety-analyses&utm_source=website&utm_medium=cta&utm_campaign=features_concepts) [View Pricing Plans](https://iso26262.academy/pricing)