Mooney M20K accident near Watertown, Wisconsin, November 28, 1986
On November 28, 1986 at about 11:35 pm local time, a Mooney M20K, registered N3691H, was substantially damaged in an accident near Watertown, Wisconsin. It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 28, 1986 · about 11:35 pm local time
- Place
- Watertown, Wisconsin · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mooney M20K · all M20Ks on the register
- Registration
- N3691H · registry record · serial 250431
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
FOLLOWING AN ENGINE POWER LOSS DUE TO FATIGUE OF THE #1 CYLINDER, THE PLT FORCE LANDED THE ACFT ON A HIGHWAY. THE HIGHWAY WAS THE ONLY AVAILABLE LANDING AREA, ACCORDING TO THE PLT. ON LANDING ROLLOUT, THE PLT WAS FORCED TO SWERVE THE ACFT OFF THE PAVED SURFACE TO AVOID ON COMING VEHICULAR TRAFFIC. THE ACFT STRUCK TWO TRAFFIC SIGNS AND SUBSEQUENTLY WENT INTO A DITCH ALONG THE SIDE OF THE ROAD. ALTHOUGH THE SYLINDER APPEARED TO HAVE BEEN PROPERLY MANUFACTURED, ACCORDING TO TELEDYNE CONTINENTAL METALLURGICAL DATA THE ISOLATED LOCATION OF THE FATIGUE POINTS AND THE ABSENCE OF OTHER POSSIBLE CAUSES OF THE CYLINDER FAILURE INDICATE THAT A MANUFACTURING DEFECT EXISTED.
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
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 500 hours in all; 6 in this make and model; 122 in the last 90 days; 365 as pilot in command
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 1,332 hours
- Last inspection: annual inspection, January 6, 1986; 7 hours since
- Maximum gross weight: 2,740 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental TSIO-360-GB1 (piston); 0 hours total
The flight
- Departed from: OSH Oshkosh WI at 10:00 pm
- Destination: RFD Rockford IL
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: night, dark
- Wind: from 250° at 5 knots
- Visibility: 10 statute miles
- Sky: scat at 25,000 ft
- Temperature: 36°F (2°C), dew point 30°F (-1°C)
- Altimeter: 30.00 inHg
- Observation at 11:50 pm from MSN, 25 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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.