# NTSB CEN25LA246: Thorp T18, N18CH, Lake Elmo, MN, July 6, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: July 6, 2025, 10:56 local (15:56 UTC) - Place: Lake Elmo, MN - Coordinates: 44.994399, -92.85413 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.9944&lon=-92.8541&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: FAA Minneapolis FSDO - NTSB case key (mKey): 200507 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN25LA246 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/200507/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=200507 - Page: https://openairdocs.org/ntsb/CEN25LA246 ## Probable cause 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. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8951049), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=8951049), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Landing gear system: nose/tail landing gear](https://openairdocs.org/ntsb-findings/01023220): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01023220/cases.md?model=8951049), [All aircraft, 185 cases](https://openairdocs.org/ntsb-findings/01023220/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=8951049), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR go-around: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=8951049), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Approach-VFR go-around: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=8951049), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=8951049), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Hoots THORP T-18, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=8951049), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis 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. ## Aircraft - Registration: [N18CH](https://openairdocs.org/aircraft/N18CH), registered now, S/N CH374, built 1974 (OpenAirDocs) - Reported make and model: THORP T18 (UNDESIGNATED SERIES) - Registry model: [Hoots THORP T-18](https://openairdocs.org/model/hoots-thorp-t-18) (registry code 8951049) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: CH374 - Year built: 1974 - Airframe hours: 1400 - Engines: Lycoming Engines O-360-A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, February 13, 2025, 1 hours before - Departed: MY66, Onamia, MN - Destination: 21D, Lake Elmo, MN - Airport: 21D, Lake Elmo, runway 14/32, 3,504 × 75 ft, asphalt - Equipment: Electronic primary flight display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 85; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; medical: basicmed, with waivers/limitations; last flight review July 13, 2025; seat: left; restraint: 4-point; flight hours: 3,425 total, 375 in this make and model, 20 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 63 °F - Altimeter: 29.98 inHg - Observed at: KSTP, 9 nm away - METAR: KSTP 061553Z 32007KT 10SM CLR 25/17 A2998 RMK AO2 SLP145 T02500167 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20250706010889A](https://openairdocs.org/incident/20250706010889A), Jul 6, 2025: Hoots THORP T-18, Lake Elmo, MN, Substantial damage. PIC departed the destination airport and returned to his home airport. PIC stated that while attempting to land he was off to the left of the runway and… ## Docket (2 files) The files NTSB released with the investigation on September 5, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=200507. 3.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19085193&FileExtension=pdf&FileName=NTSB%20Form%206120_1_Redacted-Rel.pdf - Investigation photographs (item 2, PDF, 5 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19085203&FileExtension=pdf&FileName=Investigation%20Photographs-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.