Thorp T18 accident near Lake Elmo, Minnesota, July 6, 2025
On July 6, 2025 at about 3:56 pm local time, a 1974 Thorp T18, an amateur-built aircraft,, registered N18CH, was substantially damaged in an accident during landing (flare/touchdown) near Lake Elmo, Minnesota (Lake Elmo 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).
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The NTSB's probable cause their words, unchanged
The pilot’s failure to maintain obstacle clearance during the go-around, that resulted in the tailwheel impacting a taxiway sign, a subsequent loss of control due to the damaged tailwheel, and a runway excursion during the landing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 6, 2025 · about 3:56 pm local time
- Place
- Lake Elmo, Minnesota · Lake Elmo · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Thorp T18 UNDESIGNAT, built 1974, amateur-built · all T18s on the register
- Registration
- N18CH · registry record · serial CH374
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
After the completion of the local area flight, the pilot maneuvered the airplane for the approach to the runway. The airplane was not oriented with the runway during approach, so the pilot applied full engine power to perform a go-around. During the go-around, the tailwheel impacted a taxiway sign, and the tailwheel sustained damage. The pilot completed the go-around and landed on the runway. During the landing, there was no tailwheel control due to the previous impact damage from the taxiway sign, and the airplane departed the runway to the right. The airplane came to rest upright on a grass field near the runway. The pilot was able to egress from the airplane without further incident. The airplane sustained substantial damage to the rudder and the underside of the empennage. The pilot reported there were no preimpact mechanical malfunctions or failures with the airframe or the engine that would have precluded normal operation.
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
- Collision with terrain or object (not controlled flight into terrain) during approach (VFR go-around)
- Loss of control on ground during landing (flare/touchdown) defining event
- Runway excursion during landing (landing roll)
- Attempted remediation/recovery during approach (VFR go-around)
The NTSB's findings
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Directional control › Attain/maintain not possible
- Aircraft › Aircraft systems › Landing gear system › Nose/tail landing gear › Damaged/degraded
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Altitude › Not attained/maintained
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land
- Flight time: 3,425 hours in all; 375 in this make and model; 20 in the last 90 days
- Last flight review: July 13, 2025
- Medical certificate: BasicMed (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 1,400 hours
- Last inspection: condition inspection, February 13, 2025; 1 hours since
- Maximum gross weight: 1,700 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming Engines O-360-A1A (piston); 1,396 hours total
The flight
- Departed from: MY66 Onamia MN at 3:28 pm
- Destination: 21D Lake Elmo MN
- Flight plan: none
- Runway 14/3, 3,504 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 320° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 77°F (25°C), dew point 63°F (17°C)
- Altimeter: 29.98 inHg
- Observation at 10:53 am from KSTP, 9 miles away
Weather report (METAR): KSTP 061553Z 32007KT 10SM CLR 25/17 A2998 RMK AO2 SLP145 T02500167
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on September 5, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 2 | Investigation Photographs | PDF, 5 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number CEN25LA246.