Cessna 172RG accident near Tomahawk, Wisconsin, August 2, 2008
On August 2, 2008, a Cessna 172RG, registered N6520R, was substantially damaged in an accident during enroute (cruise) near Tomahawk, Wisconsin (Tomahawk Regional Airport). It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 2, 2008
- Place
- Tomahawk, Wisconsin · Tomahawk Regional Airport · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172RG · all 172RGs on the register
- Registration
- N6520R · no longer on the register · serial 172RG0189
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
- Loss of engine power (partial) during emergency descent
- Loss of engine power (total) during emergency descent
- Off-field or emergency landing during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng oil sys › Not specified
- cause Aircraft › Fluids/misc hardware › Fluids › Oil › Fluid level
- factor Environmental issues › Physical environment › Terrain › (general) › Contributed to outcome
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 119 hours in all; 31 in this make and model; 2 in the last 90 days; 2 in the last 30 days; 44 as pilot in command
- Last flight review: July 23, 2008
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 6,840 hours
- Last inspection: annual inspection, October 11, 2007
- Maximum gross weight: 2,650 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360-F1A6 (piston); 0 hours total
- Operator: 6520R LLC
The flight
- Departed from: TKV Tomahawk WI
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 340° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 52°F (11°C)
- Altimeter: 29.90 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.