Introduction

In addition to analyzing dependent failures, safety-critical systems must also consider systematic failures that arise from design flaws, specification gaps, and process deficiencies. Systematic Failure Mode and Effects Analysis (SFMEA) is a crucial methodology under ISO 26262-4, Clause 8, ensuring that systematic faults are identified and mitigated at the design phase. But why is SFMEA necessary, and what risks does it address?

Problem Statement

Unlike random hardware failures, systematic failures originate from incorrect specifications, logic errors, or poorly defined system behaviors. These failures are particularly challenging because they:

• Do not follow probabilistic models: Unlike hardware failures, systematic faults cannot be predicted using failure rates.
• Are design-induced: A single mistake in architecture, requirements, or implementation can cause a system-wide failure.
• Can impact safety goals despite redundancy: Even fault-tolerant systems may be compromised by incorrect safety mechanisms or improper diagnostic coverage.
• Require a structured verification approach: Ensuring compliance with ISO 26262-4, Clause 8, demands a comprehensive assessment of failure modes in software, hardware, and architecture.

Essential Inputs for SFMEA

• Functional and Technical Safety Concepts (ISO 26262-3, Clause 7)
• Failure Mode Analysis at System and Subsystem Levels
• Failure Propagation and Software-Hardware Interaction Study
• Safety Mechanism Effectiveness Evaluation

Without SFMEA, systematic failures can remain undetected until late development stages, leading to costly redesigns, regulatory hurdles, and potential safety-critical failures.

Conclusion

Systematic FMEA is a critical safety analysis technique to identify and mitigate design-induced failures. Reach out to us to learn how SFMEA can strengthen your system architecture and enhance compliance with ISO 26262.