Schempp-Hirth VENTUS B/16.6 accident near Lake Cobb, California, April 7, 1991
On April 7, 1991 at about 10:00 pm local time, a Schempp-Hirth VENTUS B/16.6 (glider), registered N81PT, was substantially damaged in an accident near Lake Cobb, California. 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
THAT THE PILOT'S VISUAL LOOKOUT WAS IMPROPER. CONTRIBUTING TO THIS ACCIDENT WAS THE UNMARKED TRANSMISSION WIRE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 7, 1991 · about 10:00 pm local time
- Place
- Lake Cobb, California · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Schempp-Hirth VENTUS B/16.6 VENTUS B/1 · all VENTUS B/16.6s on the register
- Registration
- N81PT · registry record · serial 258
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
AFTER THE AERO TOW RELEASED THE PILOT SOARED TO MT. ST. HELENA AND THEN ONTO COBB MOUNTAIN WHERE THERMAL LIFT WAS REPORTED. UPON ARRIVING OVER COBB MOUNTAIN HE DID NOT ENCOUNTER ANY THERMAL LIFT. REALIZING A FORCED LANDING WAS IMMINENT THE PILOT SELECTED A OFF-FIELD LANDING AREA WHICH WAS SURROUNDED ON THREE SIDES. THE PILOT REPORTED THAT THE NORTHWEST SIDE OF THE FIELD WAS UNOBSTRUCTED EXCEPT FOR A SMALL WIRE FENCE WHICH POSED NO PROBLEM FOR THE OFF-FIELD LANDING. THE PILOT FAILED TO SEE A SMALL TRANSMISSION WIRE WHICH CROSSED THE FINAL APPROACH COURSE ABOUT 25 FEET ABOVE GROUND LEVEL. THE GLIDER STRUCK THE WIRE WHICH CAUSED THE GLIDER TO NOSE DOWN ABOUT 40 DEGREES AND STRIKE THE GROUND IN A WINGS LEVEL ATTITUDE.
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: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: glider
- Flight time: 23,125 hours in all; 355 in this make and model; 9 in the last 90 days; 4 in the last 30 days; 17,055 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded, January 2, 2000
- Maximum gross weight: 1,102 lb
- Seats: 1
- Landing gear: fixed
- Engine: (type not recorded); 0 hours total
The flight
- Departed from: Vacaville CA at 7:00 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.
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.