Amateur-built DISCUS CS accident near Williams, California, August 2, 2009
On August 2, 2009 at about 6:39 pm local time, a amateur-built DISCUS CS (glider), registered N7HV, was substantially damaged in an accident during initial climb near Williams, California (Williams Gliderport airport). It was a glider-towing flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance with terrain after intentionally releasing from the tow plane at a low altitude during the initial climb.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 2, 2009 · about 6:39 pm local time
- Place
- Williams, California · Williams Gliderport · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built DISCUS CS
- Registration
- N7HV · registry record · serial 26SCS
- Damage
- Substantial damage
- Flight
- Glider-towing flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
After taking off, the lead pilot in a dual tow elected to perform a precautionary release as a result of a "slack-line" condition. The trail pilot, realizing that his tow rope was now under the lead pilot's right wing, released his tow rope and immediately turned right. Without sufficient altitude or airspeed to return to the airport, the trail pilot tried to level the glider's wings, but could not before the right wing tip impacted terrain. The glider sustained substantial damage to its right wing and empennage.
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
- Glider tow event during initial climb defining event
- Collision with terrain or object (not controlled flight into terrain) during maneuvering
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › (general) › Incorrect use/operation
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: private
- Ratings: rotorcraft: glider
- Flight time: 1,699 hours in all; 1,072 in this make and model; 194 in the last 90 days; 77 in the last 30 days; 1,699 as pilot in command
- Last flight review: April 6, 2008
- Medical certificate: None
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 1,152 hours
- Last inspection: annual inspection, May 10, 2009
- Maximum gross weight: 1,125 lb
- Seats: 1
- Landing gear: retractable
The flight
- Departed from: CN12 Williams CA at 6:38 pm
- Destination: CN12 Williams CA
- Flight plan: none
- Runway 34, 2,500 ft by 40 ft
Weather at the time
- Light: daylight
- Wind: from 200° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 79°F (26°C), dew point 54°F (12°C)
- Altimeter: 29.94 inHg
- Observation at 6:53 pm from MYV, 33 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.