# NTSB CEN25LA405: Sukhoi SU-26MX, N25SU, Longmont, CO, September 30, 2025 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: September 30, 2025, 11:00 local (17:00 UTC) - Place: Longmont, CO - Coordinates: 40.16378, -105.16222 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.1638&lon=-105.1622&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report March 13, 2026 - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: FAA-FSDO - NTSB case key (mKey): 201792 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN25LA405 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/201792/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=201792 - Page: https://openairdocs.org/ntsb/CEN25LA405 ## Probable cause The pilot's failure to maintain directional control during takeoff. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Sukhoi SU-26MX, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=9850102), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Sukhoi SU-26MX, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=9850102), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Sukhoi SU-26MX, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=9850102), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Takeoff: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Sukhoi SU-26MX, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=9850102), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Takeoff: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Sukhoi SU-26MX, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=9850102), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot reported that during the takeoff roll about 50 mph, the airplane veered to the left of the runway centerline. The pilot attempted to correct back to the right; however, the airplane continued to the left, exited the left side of the runway, and then momentarily became airborne. Subsequently, the left wing struck the ground which resulted in substantial damage to the left wing. The pilot reported that he might have attempted the takeoff with the tailwheel in the unlocked position. ## Aircraft - Registration: [N25SU](https://openairdocs.org/aircraft/N25SU), registered now, S/N 5204, built 1991 (OpenAirDocs) - Reported make and model: SUKHOI SU-26MX - Registry model: [Sukhoi SU-26MX](https://openairdocs.org/model/sukhoi-su-26mx) (registry code 9850102) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: 5204 - Year built: 1991 - Airframe hours: 405 - Engines: Veeleneev M14P 400 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, April 10, 2025 - Destination: Same as departure - Airport: LMO, Vance Brand, runway 11, 4,799 × 75 ft, concrete - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 76; injuries: minor; airline transport; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 25, 2025; seat: center; restraint: 5-point; flight hours: 22,202 total, 15 in this make and model, 11 in the last 90 days, 9 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 45 °F - Altimeter: 30.12 inHg - Observed at: KLMO - METAR: METAR KLMO 301655Z AUTO 00000KT 10SM CLR 20/07 A3012 RMK AO2 T02020073= ## 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 20250930016839A](https://openairdocs.org/incident/20250930016839A), Sep 30, 2025: Sukhoi SU-26MX, Longmont, CO, Substantial damage. Takeoff on runway 11. Loss of control occurred early in the takeoff roll , the aircraft veered left and departed the runway. It became airborne for 4 seconds… ## Docket (3 files) The files NTSB released with the investigation on March 13, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=201792. 5.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 4.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19728928&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photo array (item 2, PDF, 2 pages, 955 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19728961&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Memorandum for record a�� FAA summary (item 3, PDF, 1 page, 48 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19962090&FileExtension=pdf&FileName=FAA%20MOR-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.