Amateur-built EAA BIPLANE accident near Wilksville, Ohio, December 16, 1991
On December 16, 1991 at about 9:10 pm local time, a amateur-built EAA BIPLANE, registered N9601, was substantially damaged in an accident near Wilksville, Ohio. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE RESTRICTED VISIBILITY OF THE PILOT DUE TO OIL ON THE WINDSHIELD AND HIS GOGGLES, WHICH RESULTED IN A TREE STRIKE AND UNCONTROLLED TOUCHDOWN, DURING THE EXECUTION OF A PRECAUTIONARY LANDING. FACTORS RELATED TO THE ACCIDENT WERE A CLOGGED CRANKCASE BREATHER TUBE, THE LACK OF A WHISTLE SLOT ON THE CRANKCASE BREATHER TUBE, AND THE TREES.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 16, 1991 · about 9:10 pm local time
- Place
- Wilksville, Ohio · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built EAA BIPLANE EAA BIPLAN
- Registration
- N9601 · no longer on the register · serial 1
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT WAS IN CRUISE FLIGHT, IN AN EXPERIMENTALLY CERTIFIED AIRPLANE, WHEN THE CRANKCASE BREATHER WHICH WAS NOT PRESSURIZED WITH A WHISTLE SLOT FROZE UP. THE CRANKCASE PRESSURIZED AND THE CRANKCASE SEAL WAS DISLODGED. THE PILOT MADE A PRECAUTIONARY LANDING IN A FIELD OF LIMITED SIZE, SURROUNDED BY TREES. DUE TO THE RESTRICTED VIIBILITY OF THE PILOT, WITH OIL ON HIS GOGGLES AND WINDSHIELD, HE STRUCK A TREE ON FINAL AND MADE AN UNCONTROLLED TOUCHDOWN IN THE FIELD. THE INVESTIGATION REVEALED THERE IS A REQUIREMENT OF A WHISTLE SLOT ON NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES, HOWEVER, THIS REQUIREMENT DOES NOT EXIST FOR EXPERIMENTAL CATEGORY AIRPLANES.
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: private
- Ratings: single-engine land
- Flight time: 189.5 hours in all; 36 in this make and model; 36.7 in the last 90 days; 14.1 in the last 30 days; 151 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 185 hours
- Last inspection: annual inspection, June 24, 1991; 70 hours since
- Maximum gross weight: 1,163 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming O-290-D (piston); 0 hours total
The flight
- Departed from: LOZ London KY at 6:20 pm
- Destination: UNI Athens OH
- Flight plan: VFR
- Runway 0
Weather at the time
- Light: daylight
- Wind: at 8 knots
- Visibility: 15 statute miles
- Sky: overcast at 1,000 ft; not recorded
- Temperature: 36°F (2°C), dew point 0°F (-18°C)
- Observation at 9:00 pm from HTS, 50 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.
Other NTSB records under N9601 the same tail number, which may have belonged to a different aircraft at the time
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.