Thorp T-18CW accident near Wimberley, Texas, July 5, 1991
On July 5, 1991 at about 6:18 pm local time, a Thorp T-18CW, an amateur-built aircraft,, registered N83MK, was substantially damaged in an accident near Wimberley, Texas (Woodbreck airport). It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE FAILURE OF THE AIRPORT PERSONNEL TO MAINTAIN THE AIRSTRIP IN AN OPERABLE CONDITION AND THE PILOTS FAILURE TO MAINTAIN RUNWAY ALIGNMENT ON TOUCHDOWN.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 5, 1991 · about 6:18 pm local time
- Place
- Wimberley, Texas · Woodbreck
- Type
- Accident
- Injuries
- 1 person had minor injuries; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Thorp T-18CW, amateur-built · all T-18CWs on the register
- Registration
- N83MK · registry record · serial 1367
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
DURING A LANDING ON A GRASS AIRSTRIP THE PILOT FAILED TO MAINTAIN RUNWAY ALIGNMENT ON TOUCHDOWN AND LOST CONTROL WHEN HIS LEFT MAIN WHEEL ENTERED LONG GRASS. LEFT WING CONTACTED 5 FOOT TALL WEEDS ADJACENT TO THE 40 FEET WIDE AIRSTRIP. THE AIRPLANE VEERED LEFT AND STRUCK A LARGE ANT MOUND RESULTING IN THE AIRPLANE GROUND LOOPING TO THE INVERTED POSITION. THE PILOT REPORTED THAT TOUCHDOWN OCCURRED TEN FEET LEFT OF RUNWAY CENTER.
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: 2,594 hours in all; 740 in this make and model; 40 in the last 90 days; 15 in the last 30 days; 2,502 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 1,769 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-360 (piston); 0 hours total
The flight
- Departed from: T98 San Marcos TX at 6:05 pm
- Flight plan: none
- Runway 15, 2,200 ft by 40 ft
Weather at the time
- Light: daylight
- Wind: from 140° at 5 knots
- Visibility: 15 statute miles
- Sky: scat at 4,000 ft
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
- Observation at 5:50 pm from AUS, 40 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.