As+ Ltd AC-4B accident near Sundance, Wyoming, September 14, 1997
On September 14, 1997 at about 11:45 pm local time, a As+ Ltd AC-4B (glider), registered N3021, was substantially damaged in an accident near Sundance, Wyoming (Private Strip 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 visual conditions (good weather).
The NTSB's probable cause their words, unchanged
improper planning/decision by the pilot, which led to a snag and sudden slack in the tow rope, and necessitated an aborted launch (emergency landing) after initial liftoff. This in turn led to an inadvertent stall, a wing drop, and the left wing tip dragging the ground. A factor relating to the accident was: the restricted movement of the tow rope after it became snagged on the crop stubble.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 14, 1997 · about 11:45 pm local time
- Place
- Sundance, Wyoming · Private Strip · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- As+ Ltd AC-4B · all AC-4Bs on the register
- Registration
- N3021 · registry record · serial 23
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
A glider launch was being conducted, using a vehicle tow and a mechanical advantage/pulley arrangement. During the launch, the tow rope became snagged on vegetation (alfalfa crop stuble), then slack developed in the tow rope as the rope came loose from the stuble. When slack was taken up, it 'jerked' the glider, which pitched up. The pilot released the tow rope, but the glider settled (stall) and rolled approximately 25 degrees left wing down. The wing contacted the ground, and the glider spun around and came to rest facing backwards. This resulted in substantial damage to the wings and fuselage.
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, flight instructor
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane single-engine; instructor: glider; instrument: airplane; rotorcraft: glider
- Flight time: 4,551 hours in all; 3 in this make and model; 4 in the last 90 days; 3 in the last 30 days; 2,836 as pilot in command; 948 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 8 hours
- Last inspection: annual inspection, July 20, 1997; 4 hours since
- Maximum gross weight: 551 lb
- Seats: 1
- Landing gear: fixed
- Engine: (type not recorded); 0 hours total
The flight
- Flight plan: none
- Runway 22, 2,200 ft by 500 ft
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: scat at 6,000 ft
- Temperature: 84°F (29°C), dew point 43°F (6°C)
- Altimeter: 29.00 inHg
- Observation at 11:50 pm from GCC, 47 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.
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.