14 CFR Part 5 · ICAO Doc 9859 (4th ed.)
SMS Hazard Risk Matrix
Click any cell to assess a hazard: Likelihood (rows A–E) × Severity (columns 1–5). Get the risk level, required action, and regulatory citations.
Click to assess — Likelihood (rows) × Severity (columns)
| Likelihood ↓ / Severity → | 1 Catastrophic | 2 Hazardous | 3 Major | 4 Minor | 5 Negligible |
|---|---|---|---|---|---|
| A — Frequent | |||||
| B — Occasional | |||||
| C — Remote | |||||
| D — Improbable | |||||
| E — Extremely |
H
HIGHM
MEDIUML
LOWClick a cell in the matrix to see the risk level, required action, and citations.
14 CFR Part 5 · ICAO Doc 9859 (4th ed.)
This matrix follows the ICAO Safety Management Manual (Doc 9859) risk classification scheme adopted by the FAA in its SMS regulations (Part 5). Your approved SMS may use a different matrix — always apply the version in your approved SMS Manual.
Likelihood definitions
AFrequent — Likely to occur many times. Has occurred frequently in similar operations.
BOccasional — Likely to occur sometimes. Has occurred infrequently in similar operations.
CRemote — Unlikely but possible. Has occurred rarely in similar operations.
DImprobable — Very unlikely to occur. Not known to have occurred in similar operations.
EExtremely Improbable — Almost inconceivable. Occurrence possible but extremely unlikely.
Severity definitions
1Catastrophic — Equipment destroyed. Multiple fatalities. Loss of aircraft.
2Hazardous — Large reduction in safety margins, physical distress, serious or fatal injury to a small number of persons, major equipment damage.
3Major — Significant reduction in safety margins, serious incident, minor injuries, major equipment damage.
4Minor — Nuisance, operating limitations, use of emergency procedures, minor incident, no injuries.
5Negligible — Little to no consequence. No threat to safety.
Advisory only. Risk assessment is a judgment-based process — two qualified safety professionals may classify the same hazard differently. This matrix is a decision-support tool, not a substitute for a trained Safety Manager or an approved SMS.
Frequently asked questions
What is an SMS hazard risk matrix?
A risk matrix is the core assessment tool in a Safety Management System (SMS). It scores a hazard by combining likelihood (how often could it occur?) with severity (how bad if it does?). The intersection of the two dimensions gives you a risk level — HIGH, MEDIUM, or LOW — that drives what action your organization must take. The 5x5 matrix here follows the ICAO Doc 9859 framework adopted by the FAA in its SMS regulations.
What regulation requires an SMS for Part 135 operators?
14 CFR Part 5 requires most Part 121 and Part 135 operators to implement an SMS. Part 5 became effective in 2018 for Part 121 operators; the FAA has been phasing in Part 135 SMS requirements. Even where not yet mandated, an SMS is a best practice and is required for certain international operations and by many insurance underwriters.
What do the likelihood categories A–E mean?
Likelihood A = Frequent (likely to occur many times; has occurred frequently in similar operations). B = Occasional (has occurred infrequently). C = Remote (unlikely but possible; has occurred rarely). D = Improbable (very unlikely; not known to have occurred in similar operations). E = Extremely Improbable (almost inconceivable).
What do the severity categories 1–5 mean?
Severity 1 = Catastrophic (equipment destroyed, multiple fatalities). 2 = Hazardous (large reduction in safety margins, serious injury to a small number). 3 = Major (significant reduction in safety margins, serious incident, minor injury). 4 = Minor (nuisance, emergency procedures used, no injuries). 5 = Negligible (little to no consequence).
Is a HIGH risk always a show-stopper?
Yes — in standard SMS practice a HIGH risk means the operation must not commence (or must halt) until mitigation reduces the risk to an acceptable level. HIGH risk requires immediate escalation to senior management, a formal mitigation plan, and tracking until controls are verified. Proceeding with a known HIGH risk without controls is a serious SMS failure.
Clearspar builds SMS risk assessment into every dispatch gate.
Hazards are logged, risk-scored, and tracked to closure — automatically surfaced when a similar flight profile reappears.
See Clearspar