CEN15LA028 · Huebbe Sonex HB
Huebbe Sonex HB · Accident: powerplant system/component malfunction/failure en route
From Taylorville, IL to St. Charles, MO
Event
- NTSB case
- CEN15LA028
- 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
- 1 · 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
Huebbe Sonex HB
- Aircraft type
- Huebbe SONEX HB
- 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
- N244HB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Taylorville, ILTo St. Charles, MO
- Aircraft age
- About 4 years (built 2010)
- 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
- En route · cruise
- Defining eventThe 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
- Powerplant system/component malfunction/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
- Aircraft › Aircraft power plant
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The private pilot and a sport pilot-rated passenger were conducting a personal cross-country flight in the experimental amateur-built airplane, which was powered by an uncertified automotive engine. The airplane was in cruise flight when it experienced a total loss of engine power. The pilot(s) attempted a forced landing on a field, during which the airplane nosed over. The wreckage path through the field was about 200 ft long, which was consistent with excessive energy/speed upon touchdown.
A review of maintenance logbook entries revealed that the engine had been assembled by the owner and that the camshaft and crankshaft had been removed when work was performed on the engine about 3 years before the accident. Postaccident examination of the engine indicated that the crankshaft had fractured due to a fatigue crack that had initiated at a fillet radius at the forward end of the No. 2 main bearing journal where the journal transitioned to the forward cheek. The cause of the fatigue crack could not be determined.
Probable cause
The loss of engine power during cruise flight due to a fatigue fracture of the crankshaft, which resulted in a forced landing on unsuitable terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN15LA028
- Event ID
- 20141027X62323
- Case number
- CEN15LA028
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: d5f25dea2fb74f315d7f8680927cb828956c065f24754b65fe67e67ebcb92f24; retrieved 2026-09-14T17:28:06.338Z.