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Standard · MIL-STD-882E
MIL-STD-882 — Fault Tree Analysis for Defence System Safety
MIL-STD-882E Department of Defense Standard Practice — System Safety is the U.S. defence system-safety standard. It mandates a System Safety Program (SSP) over the lifecycle and names FTA as a recommended technique within Tasks 205 (PHA), 206 (SSHA / SHA) and 207 (O&SHA), with quantified results feeding the Risk Assessment Code (RAC) matrix and the final Safety Assessment Report (SAR).
Where MIL-STD-882 calls for FTA
FTA in MIL-STD-882E is invoked through several Section 4 and Appendix A tasks:
- Task 205 — Preliminary Hazard Analysis (PHA): identifies top events; FTA decomposes them.
- Task 206 — Subsystem / System Hazard Analysis (SSHA / SHA): FTA verifies that subsystem architecture caps the residual risk in the RAC matrix.
- Task 207 — Operating & Support Hazard Analysis (O&SHA): FTA on operational scenarios including human factors and maintenance.
- Task 301 — Safety Assessment Report (SAR): FTA outputs are part of the residual-risk evidence presented to the Component Acquisition Executive (CAE).
The Risk Assessment Code (RAC) matrix
| Severity | Catastrophic | Critical | Marginal | Negligible |
|---|---|---|---|---|
| Frequent | 1 (high) | 3 | 7 | 13 |
| Probable | 2 | 5 | 9 | 16 |
| Occasional | 4 | 6 | 11 | 18 |
| Remote | 8 | 10 | 14 | 19 |
| Improbable | 12 | 15 | 17 | 20 (low) |
FTA's role is to produce the quantitative top-event probability that selects the row of the RAC matrix; severity is set by the consequence analysis. RAC ≤ 6 normally requires Component Acquisition Executive sign-off.
How FTA Studio supports MIL-STD-882
- IEC 61025 symbol set — the standard FTA notation MIL-STD-882 expects.
- Mission time configurable per project — the SAR may target an exposure window of one mission, an operational period, or system life.
- Hazard register (Enterprise) — captures top events and links them to the FTA tree, the FMEA, and the RAC scoring.
- Risk matrix view (Enterprise) — visualises the RAC for the full hazard register.
- Approval workflow (Enterprise) — captures the engineering and safety-board sign-offs the SAR requires.