Mooney M20K accident near Sheboygan, Wisconsin, June 21, 2015
On June 21, 2015 at about 4:30 pm local time, a 1982 Mooney M20K, registered N1168Z, was substantially damaged in an accident during initial climb near Sheboygan, Wisconsin (Sheboygan County Mem airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
Oil starvation due to preignition in the No. 5 cylinder as a result of failed spark plugs; the top and sides of the piston head were eroded, which allowed the exhaust gases caused by the preignition to pressurize the crankcase and force engine oil out of the breather tube.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 21, 2015 · about 4:30 pm local time
- Place
- Sheboygan, Wisconsin · Sheboygan County Mem · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Mooney M20K, built 1982 · all M20Ks on the register
- Registration
- N1168Z · no longer on the register · serial 25-0697
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Shortly after takeoff, the pilot advised air traffic control that he was returning to the airport due to low oil pressure. The engine subsequently lost power, and the pilot was forced to land in a wheat field 5 miles south of the airport. During on-site examination of the airplane, no oil was found in the crankcase, and subsequent examination of the engine and turbocharger revealed that the turbocharger was dry. Further examination of the engine revealed evidence of preignition in the No. 5 cylinder that appeared to have been caused by failed spark plugs. The top and sides of the piston head were eroded, which allowed the exhaust gases caused by the preignition to pressurize the crankcase and force engine oil out of the breather tube.
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
- Loss of engine power (total) during initial climb defining event
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Failure
- factor Aircraft › Fluids/misc hardware › Fluids › Oil › Related operating info
Pilot
- Certificate: private
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 3,570 hours in all; 3,270 in this make and model; 3,570 as pilot in command
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Last inspection: approved inspection programme
- Maximum gross weight: 2,900 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental TSIO-520-MB (piston); 1,100 hours total
The flight
- Departed from: KSBM Sheboygan WI at 4:05 pm
- Destination: KEKM Elkhart IN
- Flight plan: IFR
Weather at the time
- Light: daylight
- Wind: from 150° at 5 knots
- Visibility: 1.8 statute miles
- Sky: broken clouds at 3,100 ft; scat at 1,400 ft
- Temperature: 70°F (21°C), dew point 66°F (19°C)
- Altimeter: 29.81 inHg
- Observation at 4:33 pm from KSBM, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 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.