Benjamin Admin
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P1 of the auto-FMEA build plan: establish the public-domain methodology foundation (no AIAG-VDA/SAE/IEC tables reproduced). - fmea_data_sources.go: MIL-STD-882E severity (Cat I-IV→1-10) + probability (A-F→1-10 with per-hour λ bands), OccurrenceFromRate(λp·α), SeverityForCategory, MIL-STD-1629A CriticalityCm = λp·α·β·t. Own 1-10 projection, government-anchored. - 4 versioned source docs (MIL-STD-1629A, MIL-STD-882E, NASA RCM, FMD-91/NPRD-91) ingested into the new RAG collection bp_iace_fmea_kb (whitelisted). - Tests for all scales/mappings/criticality (green). Next (P1 step 2): fetch FMD-91/NPRD-91 bulk λ/α tables from DTIC. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Failure-consequence & maintenance decision logic — NASA RCM (public domain)
Drives the IACE auto-FMEA "recommended action" layer and the safety-priority
rule. Ingested into bp_iace_fmea_kb.
Source
- Source: NASA — NPR 8831.2F Ch.7 (Reliability-Centered Maintenance) and NASA GSFC-HDBK-8004 (FMEA & Risk Assessment)
- License: US Government work — public domain ("cleared for public accessibility")
- Attribution:
Source: NASA NPR 8831.2F / GSFC-HDBK-8004, public domain - Retrieved: 2026-06 · Ref: nodis3.gsfc.nasa.gov / standards.nasa.gov
Safety-consequence priority (key rule)
A failure with a safety consequence is prioritised regardless of how rare it is — "safety shall be ensured at any cost; thereafter cost-effectiveness becomes the criterion." So in a SAFETY FMEA a single Catastrophic mode matters even at low occurrence — severity dominates the ranking.
Failure definition (broad)
"Any unsatisfactory condition" — loss of FUNCTION or loss of QUALITY/ acceptable performance — not only complete breakdown. (Captures drift, degradation, intermittent.)
Recommended-action decision logic (RCM)
| Failure character | Recommended task |
|---|---|
| Gives advance warning / measurable degradation | Condition-based / predictive monitoring |
| Age/wear-related, predictable | Preventive / scheduled replacement |
| Random, low consequence | Run-to-failure (corrective) |
| Hidden / no effective task | Redesign or add redundancy / detection |
This maps onto the IACE 3-step measure hierarchy (inherently safe design → safeguarding → information) for the FMEA's control/action column.
How used in IACE
- Safety-priority rule overrides pure Cm ranking when the linked ISO 12100 hazard is high-severity (the safety-FMEA bridge).
- The decision table seeds the recommended-action suggestions per failure mode.
Concepts only — IEC 61508/ISO 13849 (SIL/PL, DC, β-factor tables) are copyrighted and NOT reproduced; diagnostic-coverage / common-cause are used as generic ideas.