CHI08LA230 · Cessna 172RG
6520R Cessna 172RG · Accident: powerplant system/component malfunction/failure en route
From Tomahawk Regional Airport (TKV) to an unrecorded destination
Event
- NTSB case
- CHI08LA230
- 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
- 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
Cessna 172RG
- Aircraft type
- Cessna 172
- 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
- N6520R
- Operator
- 6520R
- Onboard fatalities
- Unknown
- Route
- From Tomahawk Regional Airport (TKV), Tomahawk, WITo 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
- 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
- Aircraft › Fluids/miscellaneous hardware
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that he noticed smoke in the cabin and turned back to the departure airport. Oil began to accumulate on the windshield, which obscured his forward visibility. He made a five-mile straight-in approach using the airplane's global positioning system. He said that he attempted to maintain 2,500 feet above mean sea level and began to lose engine power about three miles from the airport. The engine "sputtered then froze" about two miles from the airport. The pilot then made a forced landing on a field that the passenger saw out of his window. The pilot said that the airplane came to rest at the end of that field, where it impacted trees at about 30 knots. Subsequent to the accident the propeller and starter ring gear were removed. The oil plug on the nose of the engine case that covers the governor idler gear shaft was not in place and it was found in the cowling. A safety wire that had secured the oil plug was observed attached to engine case with a separation at its plug end.
Probable cause
A total loss of engine power due to a loss of all of the engine's oil as a result of the safety wire on the governor idler gear shaft's oil plug breaking, leading to the oil plug coming unscrewed. Contributing to the accident was the lack of a suitable area for a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI08LA230
- Event ID
- 20080814X01246
- Case number
- CHI08LA230
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2008-08-02.
- API snapshot SHA-256: 884d42633931d33ededda7fc7cadd07bca120f5e8db0619bb50e2a35fa4737b7; retrieved 2026-09-15T10:03:41.303Z.