# NTSB WPR26LA175: Cosmos Phase II, N145W, Prineville, OR, May 2, 2026 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: May 2, 2026, 09:53 local (16:53 UTC) - Place: Prineville, OR · airport runway - Coordinates: 44.288277, -120.90557 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.2883&lon=-120.9056&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 27, 2026 - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 202932 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR26LA175 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/202932/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=202932 - Page: https://openairdocs.org/ntsb/WPR26LA175 ## Probable cause The pilot's inability to maintain directional control during the landing roll due to a flat tire. ## 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: [Cosmos PHASE II, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=059003U), [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 · Not attained/maintained (probable cause); cases with it: [Cosmos PHASE II, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=059003U), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Landing gear system: landing gear/wheel fairing](https://openairdocs.org/ntsb-findings/01023201): Aircraft › Aircraft systems · Damaged/degraded (probable cause); cases with it: [Cosmos PHASE II, 1 case](https://openairdocs.org/ntsb-findings/01023201/cases.md?model=059003U), [All aircraft, 9 cases](https://openairdocs.org/ntsb-findings/01023201/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Cosmos PHASE II, 2 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=059003U), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Cosmos PHASE II, 1 case](https://openairdocs.org/ntsb-events/097/sequence.md?model=059003U), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md) ## Analysis The pilot of the weight-shift control trike reported that, while landing, the trike touched down and started to oscillate back and forth. Subsequently, the trike rolled over, which resulted in substantial damage to the wing and the wing mast. According to the pilot, after the accident he observed the right rear tire was flat and would not inflate during the postaccident examination. No other preaccident mechanical failures or malfunctions with the trike that would have precluded normal operation. It is likely the tire was deflated during touchdown, and the additional drag generated by the flat tire likely contributed to the oscillations during landing. ## Aircraft - Registration: [N145W](https://openairdocs.org/aircraft/N145W), registered now, S/N B0380, built 2003 (OpenAirDocs) - Reported make and model: COSMOS PHASE II - Registry model: [Cosmos PHASE II](https://openairdocs.org/model/cosmos-phase-ii) (registry code 059003U) (OpenAirDocs) - Registry engine: [Rotax SEE BOMBADIER](https://openairdocs.org/engine/rotax-see-bombadier) (registry code 55555, reciprocating) (OpenAirDocs) - Category: Weight-shift - Serial number: B0380 - Year built: 2003 - Airframe hours: 350 - Engines: Rotax 503 52 hp reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental light sport (Special) - Airport: S39, Prineville, runway 18/36, 300 × 75 ft, asphalt - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; sport pilot; medical: sport pilot; last flight review March 2, 2026; seat: center; flight hours: 171 total, 136 as pilot in command, 1 in the last 90 days, 2 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 20° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 43 °F - Altimeter: 29.98 inHg - Observed at: KRDM, 10 nm away - METAR: METAR KRDM 021656Z 02003KT 10SM CLR 16/06 A2998 RMK AO2 SLP134 T01610056 ## 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 20260502010689A](https://openairdocs.org/incident/20260502010689A), May 2, 2026: Cosmos PHASE II, Prineville, OR, Substantial damage. During landing and near the ground, with ASOS reported calm winds, the pilot stated that he seemed to be experiencing a tail wind. He noticed that we was about… ## Docket (2 files) The files NTSB released with the investigation on August 27, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=202932. 2.7 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20754275&FileExtension=pdf&FileName=NTSB%206120_Redacted-Rel.pdf - Investigation photographs (item 2, PDF, 4 pages, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20775806&FileExtension=pdf&FileName=WPR26LA175%20Accident%20Photos%20Final%202-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.