FTW99LA227 · Aeronca 11AC
Aeronca 11AC · Accident: total loss of engine power (mechanical failure) during initial climb
From F46 to an unrecorded destination
Event
- NTSB case
- FTW99LA227
- 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
- 0
- 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
Aeronca 11AC
- Aircraft type
- Aeronca 11
- 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
- N3184E
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From F46To not recorded
- 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
- Initial climb
- 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
- Total loss of engine power (mechanical failure)
- 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
- Engine assembly, crankshaft › Failure, total
- Engine assembly, crankshaft › Fatigue
- Other maintenance personnel › Maintenance, overhaul, major, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
While maneuvering in the traffic pattern, the airplane experienced a total loss of engine power. The private pilot elected to land in a field that contained 5-foot tall maize crops. Examination of the Continental A-75-8 engine revealed that the crankshaft was separated aft of the #3 connecting rod journal. Examination of the crankshaft fracture revealed that a fatigue crack had developed in a secondary radius between the journal and the cheek. The secondary radius contained machining marks. The engine's maintenance records revealed that during the last major overhaul, the crankshaft had been ground .010 inches.
Probable cause
The mechanic's improper machining of the crankshaft during a major overhaul, which resulted in a fatigue crack and subsequent failure of the crankshaft. A factor was the lack of suitable terrain for the forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW99LA227
- Event ID
- 20001212X19519
- Case number
- FTW99LA227
- 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. 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: 42112f69e4ca2d4bb6515714f03ada256316158290d13f25e8877725b427fde0; retrieved 2026-09-22T14:18:33.270Z.