Amateur-built THORP T-18 accident near Fredericksburg, Texas, October 13, 2010
On October 13, 2010 at about 3:00 pm local time, a amateur-built THORP T-18, registered N86TJ, was substantially damaged in an accident during approach (VFR pattern downwind) near Fredericksburg, Texas (Gillespie County 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
The malfunction of the throttle clamp, which resulted in the pilot's inability to control the engine's power setting.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 13, 2010 · about 3:00 pm local time
- Place
- Fredericksburg, Texas · Gillespie County · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built THORP T-18
- Registration
- N86TJ · registry record · serial C-4602
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
According to the pilot, he reduced engine power to slow the airplane for landing while on the downwind leg of the traffic pattern. He then attempted to increase power and the engine did not respond. The pilot maneuvered the airplane immediately toward the runway and it floated during the landing. When the airplane touched down, there was insufficient distance remaining to stop on the runway. The airplane departed the end of the runway and the pilot intentionally ground-looped the airplane to stay on the airport property, causing substantial damage to both wings. A postaccident examination of the engine revealed that the clamp securing the throttle controller end was allowing the cable to slip freely.
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
- Powerplant sys/comp malf/fail during approach (VFR pattern downwind) defining event
- Runway excursion during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine controls › Power lever › Malfunction
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Not attained/maintained
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 9,450 hours in all; 549 in this make and model
- Last flight review: November 15, 2008
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320 SERIES (piston); 0 hours total
The flight
- Departed from: TS65 San Angelo TX at 2:15 pm
- Destination: T82 Fredericksburg TX
- Flight plan: not recorded
- Runway 32, 5,001 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 030° at 8 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 52°F (11°C)
- Altimeter: 30.31 inHg
- Observation at 3:05 pm from T82
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.