Standardized framework
Severity definitions
Severity levels combine a degree of loss with a degree of harm, with Level 1 always the most severe. Choose the default set, the FAA Order 1030.8 set, the FAA Order 8040.4C set, the monetary-based set, or build your own — the hazard analysis event tree will use whichever set is active.
Distribution of outcomes
NTSB events and FAA AIDS incidents combined, for the years in the current analysis scope. Part 105 parachute jumping operations are excluded, as set on the FAA data page.
Combined NTSB and FAA events by severity level · default severity definitions
| Severity | Loss / harm | Events | Share |
|---|---|---|---|
| Level 1 | Destroyed OR 1 or more fatal injuries | … | — |
| Level 2 | Substantial damage OR 1 or more serious injuries | … | — |
| Level 3 | Minor damage OR 1 or more minor injuries | … | — |
| Level 4 | None AND No injuries | … | — |
| Undetermined | Damage unknown or injury split not published | … | — |
| Total | … |
Default severity definitions
4 categoriesFour categories aligned directly to the standard degrees of loss and harm, with Level 1 the most severe.
| Severity level | Degree of loss | And / or | Degree of harm |
|---|---|---|---|
| Level 1 | Destroyed | or | 1 or more fatal injuries |
| Level 2 | Substantial damage | or | 1 or more serious injuries |
| Level 3 | Minor damage | or | 1 or more minor injuries |
| Level 4 | None | and | No injuries |
FAA Order 1030.8 severity definitions
5 categoriesFive categories as expected in the pending FAA Order 1030.8, which subdivides harm by the number of people injured.
| Severity level | Degree of loss | And / or | Degree of harm |
|---|---|---|---|
| Level 1 | — | or | 1 or more fatal injuries |
| Level 2 | Destroyed | or | 3 or more serious injuries |
| Level 3 | Substantial damage | or | 1 or 2 serious injuries |
| Substantial damage | or | 3 or more minor injuries | |
| Level 4 | Minor damage | or | 1 or 2 minor injuries |
| Level 5 | None | and | No injuries |
FAA Order 8040.4C severity definitions
5 categoriesFive categories from FAA Order 8040.4C, where each level is met by one of several explicit AND / OR combinations of loss and harm.
| Severity level | Degree of loss | And / or | Degree of harm |
|---|---|---|---|
| Level 1 | Any damage | and | 3 or more fatal injuries |
| Destroyed | and | 1 or 2 fatal injuries | |
| Level 2 | Not destroyed | and | 1 or 2 fatal injuries |
| Destroyed | or | 3 or more serious injuries | |
| Level 3 | Substantial damage | or | 1 or 2 serious injuries |
| Substantial damage | or | 3 or more minor injuries | |
| Level 4 | Minor damage | or | 1 or 2 minor injuries |
| Level 5 | None | and | No injuries |
Monetary-based severity definitions
7 categoriesSeven levels set by the dollar value of each event — injuries valued with the value of a statistical life plus the estimated share of aircraft value lost — using the bands of the monetary severity model below.
| Severity level | Value per event (aircraft loss + injury harm) |
|---|---|
| Level 1 | $100M or more per event |
| Level 2 | $10M to $100M per event |
| Level 3 | $1M to $10M per event |
| Level 4 | $100k to $1M per event |
| Level 5 | $10k to $100k per event |
| Level 6 | More than $0, up to $10k per event |
| Level 7 | $0 — no damage and no injuries |
Custom severity definitions
Pick the number of levels, then build one or more cases per level. Each case sets how many aircraft are damaged or destroyed, how many people are harmed, and whether both conditions are required (AND) or either is enough (OR).
| Severity level | Aircraft damaged or destroyed | And / or | People harmed | |
|---|---|---|---|---|
| Level 1 | ||||
| Level 2 | ||||
| Level 3 | ||||
| Level 4 |
Preview
| Severity level | Degree of loss | And / or | Degree of harm |
|---|---|---|---|
| Level 1 | ≥ 1 aircraft destroyed | or | No injuries |
| Level 2 | ≥ 1 aircraft substantial damage | or | No injuries |
| Level 3 | ≥ 1 aircraft minor damage | or | No injuries |
| Level 4 | None | or | No injuries |
Monetary severity (continuous scale)
An alternative to discrete severity levels: each NTSB event and FAA AIDS incident is given a dollar value equal to harm (injuries valued with the value of a statistical life) plus loss (a share of the estimated aircraft value, set by the degree of damage). Aircraft type comes from the FAA registry; value depreciates with aircraft age down to a floor. All figures are editable estimates for analysts, and FAA incidents already investigated by the NTSB are counted once.
Each estimate has a minimum, most likely (mode) and maximum value, describing how uncertain it is. The results below use the most likely values; the ranges are kept for a probabilistic analysis. Leave min and max equal to the mode where you have no doubt.
| Degree of harm | Min | Mode | Max | |
|---|---|---|---|---|
| Value of statistical life ($) | ||||
| Fatal injury | % | |||
| Serious injury (MAIS 3) | % | |||
| Minor injury (MAIS 1) | % | |||
| FAA injury, degree unknown | % |
| Degree of loss (share of value) | Min | Mode | Max | |
|---|---|---|---|---|
| None | % | |||
| Minor damage | % | |||
| Substantial damage | % | |||
| Destroyed | % |
| Aircraft value when new ($) | Min | Mode | Max | |
|---|---|---|---|---|
| Single-engine piston airplane | ||||
| Multi-engine piston airplane | ||||
| Single-engine turboprop | ||||
| Multi-engine turboprop | ||||
| Business / other jet | ||||
| Transport jet (Part 121 / 129) | ||||
| Piston / other helicopter | ||||
| Turbine helicopter | ||||
| Glider | ||||
| Balloon / airship | ||||
| Weight-shift, powered parachute, gyroplane, other | ||||
| Aircraft type not determined |
| Depreciation | Min | Mode | Max | |
|---|---|---|---|---|
| Loss of value per year | % | |||
| Minimum value (share of new) | % | |||
| Age assumed when year unknown |
Results for 2008–2025
Calculating…