CEN21LA092 · Sonex Tailwheel
Sonex Tailwheel · Accident: loss of engine power (total) during initial climb
Event
- NTSB case
- CEN21LA092
- 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
Sonex Tailwheel
- Aircraft type
- Sonex TAILWHEEL
- 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
- N935EK
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 1 year (built 2019)
- 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
- 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
- Loss of engine power (total)
- 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
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 and builder of the airplane was conducting the airplane’s first flight. The pilot contacted the tower controller and requested to orbit the airport for 30 minutes at 3,500 ft. Shortly after departure, the pilot reported that he was unable to climb and needed to return to the airport. The pilot reported that he had a “sick engine,” and he was “just trying to make the field.” The controller reported to the pilot that smoke appeared to be coming from the engine.
Automatic Dependent Surveillance–Broadcast (ADS-B) data revealed the airplane departed from the airport, turned, and flew south for about 2 miles before it turned north back to the airport. During the subsequent forced landing, the airplane impacted powerlines and terrain and came to rest inverted about 1 mile south of the airport.
During the engine examination oil was present on the dipstick. The oil filter was cut open and fine metal pieces/powder were observed on the filter element, and small metal pieces were observed in the engine’s oil filter port. The engine was seized and could not be rotated by hand. The engine was not dissembled further, and the source of the metal filings was not determined.
The loss of engine power was attributed to the seizure of the engine; however, the reason for the engine seizure could not be determined. Investigators were unable to determine why the pilot did not stay over the airport and orbit as originally requested.
Probable cause
A total loss of engine power due to engine seizure. Contributing to the accident was the pilot decision not to orbit the airport, as originally planned.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA092
- Event ID
- 20201219102435
- Case number
- CEN21LA092
- 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, coordinates, cause areas. 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: f6179c690961eb7a80a8f080390348b41a5dcdd850cd3001feba38e352f22019; retrieved 2026-09-15T07:23:49.585Z.