IAD04CA015 · Waco ASO
Waco ASO · Accident: vortex turbulence encountered during takeoff
From Blue Grass Airport (LEX) to Lexington, KY
Event
- NTSB case
- IAD04CA015
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Waco ASO
- Aircraft type
- Waco ASO
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N11253
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Blue Grass Airport (LEX), Lexington, KYTo Lexington, KY
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Takeoff · roll/run
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Vortex turbulence encountered
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Pilot in command › Remedial action, inadequate
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot initiated his takeoff roll from a runway position where a transport airplane had previously touched down. When the pilot began the takeoff roll, the transport airplane had just cleared the runway. During the takeoff roll, airplane's tail elevation was normal until it "spontaneously" went higher. The pilot lowered the tail; however, it again went higher, and the propeller hit the runway. The pilot again tried to lower the tail, but it went higher still, with a "heavier contact of the propeller," and the airplane then nosed over. The pilot also noted that there "seemed to be some lateral turbulence during the takeoff." At the time of the accident, there was a 3-knot, quartering tailwind. According to FAA Advisory Circular 90-23F, "Aircraft Wake Turbulence," a light quartering tailwind "requires maximum caution." In addition, "Whether or not a warning or information has been given, the pilot is expected to adjust aircraft operations and flight path as necessary to preclude serious wake encounters."
Probable cause
The pilot's inadequate remedial action to wake turbulence. A factor was the pilot's failure to recognize that the takeoff conditions were conducive to wake turbulence.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record IAD04CA015
- Event ID
- 20040603X00724
- Case number
- IAD04CA015
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: bff93e79c897a690ef451feffa1b0c0081ed5f11467e021a3b46a480f2d75ae3; retrieved 2026-09-22T07:45:43.136Z.