CUE Research · Exploratory data
Aviation Incidents and Master Number 11: The Data
Three datasets for exploration: the 200 deadliest airline disasters, 1,286 fatal airline incidents since 1950, and 13,757 documented technical failures, each read by CUE’s date energies.
An 11 date is the 11th, 20th or 29th of a month, or a full date that reduces to 11 under CUE’s engine (dates whose digits total 20, 29, 38 and so on). The calendar share is how often the same kind of date occurs on the calendar in the same years. This page presents the data only.
At a glance
| Dataset | Records | On 11 dates | Share | Calendar share |
|---|---|---|---|---|
| 200 deadliest airline disasters, 1950–2025 | 200 | 50 | 25.0% | 19.7% |
| All fatal airline incidents, 1950–2025 | 1,286 | 265 | 20.6% | 19.7% |
| Technical failures (NTSB), 1982–2025 | 13,757 | 2,734 | 19.9% | 19.7% |
| Pilot- or weather-caused events (NTSB), 1982–2025 | 60,847 | 12,074 | 19.8% | 19.7% |
Fatal airline incidents, by severity
Every fatal commercial passenger incident in the dataset. Filter by severity, era or region.
265 of 1286 incidents fell on an 11 date (20.6%). Calendar share for the same years: 19.7%.
| Deaths per incident | Incidents | On 11 dates | Share | Calendar share |
|---|---|---|---|---|
| 1–4 | 227 | 51 | 22.5% | 19.7% |
| 5–9 | 112 | 24 | 21.4% | 19.7% |
| 10–19 | 163 | 36 | 22.1% | 19.7% |
| 20–49 | 342 | 57 | 16.7% | 19.7% |
| 50–99 | 256 | 51 | 19.9% | 19.7% |
| 100–149 | 112 | 29 | 25.9% | 19.7% |
| 150–199 | 45 | 12 | 26.7% | 19.7% |
| 200+ | 29 | 5 | 17.2% | 19.6% |
| Incidents on 11 dates | Other incidents | |
|---|---|---|
| Share of all deaths | 20.8% | 79.2% |
| Average deaths | 48.4 | 47.8 |
| Median deaths | 27 | 30 |
| Share with 100 or more deaths | 17.4% | 13.7% |
Technical failures, by severity
US civil aviation events where the NTSB named an equipment failure, malfunction, fatigue, design or maintenance fault as a cause. Switch to pilot- or weather-caused events, pick a period or an aircraft system.
2,734 of 13,757 events fell on an 11 date (19.9%). Calendar share for the same months and weekdays: 19.7%.
| Aircraft system | Failures | On 11 dates | Share | Calendar share |
|---|---|---|---|---|
| Engine | 5,455 | 1091 | 20.0% | 19.7% |
| Landing gear | 2,735 | 539 | 19.7% | 19.6% |
| Fuel system | 1,987 | 376 | 18.9% | 19.7% |
| Propeller or rotor | 1,190 | 245 | 20.6% | 19.7% |
| Flight controls | 895 | 176 | 19.7% | 19.7% |
| Structural | 772 | 158 | 20.5% | 19.8% |
| Electrical | 405 | 93 | 23.0% | 19.8% |
| Hydraulic | 235 | 46 | 19.6% | 19.8% |
| Avionics | 58 | 14 | 24.1% | 19.4% |
| Other | 1,000 | 192 | 19.2% | 19.9% |
Every CUE energy
The same count for each energy: the day energy equals the number, or the full date reduces to it.
| Energy | Fatal incidents | Share | Calendar | Technical failures | Share | Calendar |
|---|---|---|---|---|---|---|
| 1 | 241 | 18.7% | 19.1% | 2,754 | 20.0% | 20.6% |
| 3 | 293 | 22.8% | 22.6% | 3,122 | 22.7% | 22.6% |
| 4 | 229 | 17.8% | 16.8% | 2,337 | 17.0% | 16.6% |
| 5 | 263 | 20.5% | 19.9% | 2,756 | 20.0% | 19.8% |
| 6 | 210 | 16.3% | 15.2% | 2,145 | 15.6% | 15.7% |
| 7 | 229 | 17.8% | 19.8% | 2,707 | 19.7% | 19.8% |
| 8 | 255 | 19.8% | 19.8% | 2,737 | 19.9% | 19.8% |
| 9 | 227 | 17.7% | 19.8% | 2,697 | 19.6% | 19.8% |
| 11 | 265 | 20.6% | 19.7% | 2,734 | 19.9% | 19.7% |
| 22 | 59 | 4.6% | 5.3% | 761 | 5.5% | 5.4% |
| 33 | 83 | 6.5% | 5.3% | 656 | 4.8% | 4.7% |
By era and region
| Group | Fatal incidents | On 11 dates | Share | Calendar share |
|---|---|---|---|---|
| 1950–1969 | 365 | 71 | 19.5% | 19.7% |
| 1970–1989 | 418 | 77 | 18.4% | 19.7% |
| 1990–2009 | 348 | 75 | 21.6% | 19.7% |
| 2010–2025 | 155 | 42 | 27.1% | 19.7% |
| North America | 235 | 57 | 24.3% | 19.7% |
| Europe | 274 | 55 | 20.1% | 19.7% |
| Asia | 203 | 36 | 17.7% | 19.7% |
| Africa | 78 | 17 | 21.8% | 19.7% |
| Latin America | 132 | 28 | 21.2% | 19.7% |
| Middle East | 55 | 12 | 21.8% | 19.7% |
| No country recorded | 292 | 57 | 19.5% | 19.7% |
| Global | 1286 | 265 | 20.6% | 19.7% |
Calendar baseline: how often each energy falls on a date, 1950–2025
| Energy | Day energy | Full date | Either |
|---|---|---|---|
| 1 | 13.1% | 7.2% | 19.3% |
| 3 | 12.9% | 11.1% | 22.5% |
| 4 | 8.5% | 8.6% | 16.3% |
| 5 | 9.9% | 11.1% | 19.9% |
| 6 | 9.9% | 6.5% | 15.8% |
| 7 | 9.9% | 11.1% | 19.8% |
| 8 | 9.9% | 11.1% | 19.8% |
| 9 | 9.9% | 11.1% | 19.9% |
| 11 | 9.7% | 11.1% | 19.7% |
| 22 | 3.3% | 2.6% | 5.8% |
| 33 | 0.0% | 4.6% | 4.6% |
Source The data
- Fatal airline incidents: Wikidata records of aviation occurrences with an Aviation Safety Network ID or an airline operator, 1950–2025 (1,286 after excluding military, cargo, corporate and undated records; 213 excluded). Open data covers large disasters well and small accidents only in part. Retrieved 2026-09-28.
- Technical failures: National Transportation Safety Board aviation database (data.ntsb.gov/avdata), 93,097 US events 1982–2025, classified from NTSB’s own cause findings. Mostly general aviation; 685 technical failures are airline operations.
- Calendar shares are matched to each incident’s year (and, for NTSB events, its month and weekday), because how often a full date reduces to a number depends on the year.
- Energies from CUE’s own engine. Downloads: fatal incidents · 200 deadliest · technical failures · calendar baseline · exclusion log · sources.
Reproduce it: scripts/fetch-study-sources.mts, scripts/extract-ntsb-technical.py and the scripts/build-aviation-11*.mts and build-technology-11-study.mts builds in CUE’s code repository.