CEN22LA334 · Van's Aircraft RV-10
Van's Aircraft RV-10 · Accident: powerplant system/component malfunction/failure en route
From Dodge County Airport (UNU) to Wittman Regional Airport (OSH)
Event
- NTSB case
- CEN22LA334
- 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
Van's Aircraft RV-10
- Aircraft type
- Van's RV-10
- 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
- N4400K
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Dodge County Airport (UNU), Juneau, WITo Wittman Regional Airport (OSH), Oshkosh, WI
- Aircraft age
- About 1 year (built 2021)
- 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
- 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
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot of the airplane stated that after departure he heard a “very loud pop” from the engine and then saw smoke enter the cockpit. After the smoke cleared, he decided to perform an off-airport landing even though the engine continued to operate. He stated that he did not check the engine gauges to evaluate any anomalies. The pilot reported that the engine was operating after he heard the “loud pop” noise. During the approach to the field, the pilot added engine power to avoid hitting power lines. The airplane impacted a soccer goal, a streetlight, and a portable toilet, which resulted in substantial damage to the fuselage and right wing. Postaccident examination of the engine found the spark plug wire boot for the No. 6 cylinder was not connected to the spark plug and was found resting on the exhaust pipe. The rubber boot likely sustained thermal damage when it contacted the exhaust pipe; there were no other mechanical anomalies that would have precluded normal operation. A review of the maintenance records showed that 79.7 hours had accumulated on the engine since the last inspection, which was a condition inspection. It possible that the spark plug wire boot was not secured during the last maintenance work performed. Based on the available records, investigators were not able to determine why the spark plug wire boot was unsecured.
Probable cause
The improperly secured spark plug boot that resulted in smoke in the cockpit and a subsequent off-airport landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN22LA334
- Event ID
- 20220725105561
- Case number
- CEN22LA334
- 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, 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: 0c2327b9b08e8619a3d674eab9d1931a3a06fb18e97f7c6212fa8586fa1849fc; retrieved 2026-09-16T15:30:16.348Z.