WPR23LA149 · Stevens Kelly C RV-7
Stevens Kelly C RV-7 · Accident: part(s) separation from aircraft en route
From Skypark Airport (BTF) to an unrecorded destination
Event
- NTSB case
- WPR23LA149
- 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
Stevens Kelly C RV-7
- Aircraft type
- Stevens Kelly RV-7
- 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
- N17NK
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Skypark Airport (BTF), Bountiful, UTTo not recorded
- Aircraft age
- About 2 years (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 · 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
- Part(s) separation from aircraft
- 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 propeller/rotor
- Personnel issues › Task performance
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 reported he noticed an odor of burning oil shortly after takeoff. About a minute later, the airplane began to shake, oil covered the windscreen, and the propeller separated from the crankshaft. The pilot performed a forced landing in a snowy field, and during the landing roll the airplane nosed over and came to rest inverted. The propeller assembly was found in a field about two miles away. The most recent condition inspection was completed by the pilot one week before the accident flight, and the airplane had accrued three flight hours since the inspection. Although brass flakes were observed in the engine oil during the condition inspection, engine data recovered from the airplane’s multi-function display was consistent with normal engine operation. Five of the six propeller bolts were recovered and examined after the accident. The examination revealed fatigue cracks in multiple areas on each bolt that progressed until each bolt failed in overstress. Additionally, two of the recovered bolts displayed more extensive fatigue features than the other three bolts that were examined. The pilot documented that he had removed, inspected, and reinstalled the propeller during the condition inspection. Given this information, it is likely that the pilot/builder had not torqued all the propeller attachment bolts to the correct value, resulting in the progressive fatigue failure of the bolts.
Probable cause
The pilot/builder improperly torqued the propeller attachment bolts while reinstalling the propeller, which resulted in the fatigue failure of the bolts and the separation of the propeller assembly.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR23LA149
- Event ID
- 20230410107032
- Case number
- WPR23LA149
- 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: local date, investigation status, coordinates, cause areas. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2023-04-09.
- API snapshot SHA-256: cc91a3fa8920e7769f8ca0465b7ffe8bd9eac382ed6ed7f7bb4e39735d935f2d; retrieved 2026-09-16T17:29:41.409Z.