# NTSB CEN26LA067: Mark O Treidel American Ranger AR-1, N529MW, Denver, CO, December 16, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: December 16, 2025, 10:45 local (17:45 UTC) - Place: Denver, CO - Coordinates: 39.784194, -104.53763 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7842&lon=-104.5376&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 12, 2026 - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - Parties: Federal Aviation Administration, Denver FSDO - NTSB case key (mKey): 202193 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN26LA067 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/202193/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=202193 - Page: https://openairdocs.org/ntsb/CEN26LA067 ## Probable cause The pilot’s failure to attain rotor RPM and maintain proper rotor disc angle during takeoff which resulted in a rotor strike with the rudder. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Mark O Treidel AR-1, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=056358L), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Mark O Treidel AR-1, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=056358L), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) ## Analysis The pilot stated that it was a very windy day with winds above 20 mph and gusts to 30 mph when he attempted a takeoff in his gyroplane. He stated that during the takeoff roll with the pre-rotor engaged to 130 to140 RPM, he gently eased back on the cyclic and a gust of wind caught the rotors. He felt the rotor flap and then a bump. He immediately arrested the rotor flap and then continued the takeoff roll. When the gyroplane became airborne, he realized there was less rudder authority and returned to land at the departure airport without further incident. After landing, the pilot noticed that rudder had been damaged due to a rotor strike, which likely occurred when the rotor flapped during takeoff, resulting in substantial damage to the rudder. The pilot stated that he should have had the rotors pre-rotated to 160 RPM or greater prior to pulling back on the cyclic, and there were no preaccident mechanical malfunctions or failures of the gyroplane that would have precluded normal operation. ## Aircraft - Registration: [N529MW](https://openairdocs.org/aircraft/N529MW), registered now, S/N 0014, built 2017 (OpenAirDocs) - Reported make and model: MARK O TREIDEL American Ranger AR-1 - Registry model: [Mark O Treidel AR-1](https://openairdocs.org/model/mark-o-treidel-ar-1) (registry code 056358L) (OpenAirDocs) - Registry engine: [Rotax 914UL](https://openairdocs.org/engine/rotax-914ul) (registry code 55553, 4 cycle) (OpenAirDocs) - Category: Gyroplane, amateur-built - Serial number: 0014 - Year built: 2017 - Airframe hours: 389 - Engines: Rotax 914 115 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, March 2, 2025 - Airport: CFO, Colorado Air and Space Port Airport, runway 26, 8,002 × 100 ft, asphalt - Equipment: Handheld GPS, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 78; injuries: none; sport pilot; last flight review March 2, 2025; seat: front; restraint: 4-point; flight hours: 3,000 total, 1,200 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 19 °F - Altimeter: 29.98 inHg - Observed at: CFO ## 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 20251216019779A](https://openairdocs.org/incident/20251216019779A), Dec 16, 2025: Mark O Treidel AR-1, Watkins, CO, Substantial damage. On 12/16/2005 at 1045 MDT an experimental gyrocopter leaving Colorado Air And Space Port experienced a gust of wind causing the main rotor to contact the… ## Docket (3 files) The files NTSB released with the investigation on February 12, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=202193. 2.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19745285&FileExtension=pdf&FileName=6120%20Master%20Docket%202_Redacted-Rel.pdf - Meteorology (item 2, PDF, 2 pages, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19745142&FileExtension=pdf&FileName=METAR-Rel.pdf - Photos (item 3, PDF, 3 pages, 373 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19744880&FileExtension=pdf&FileName=Photo%20Template-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.