# NTSB WPR25LA095: Quicksilver Aeronautics L-S2S, N14QK, Geyserville, CA, February 17, 2025 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: February 17, 2025, 12:20 local (20:20 UTC) - Place: Geyserville, CA - Coordinates: 38.71781, -122.88706 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.7178&lon=-122.8871&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 199721 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR25LA095 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/199721/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=199721 - Page: https://openairdocs.org/ntsb/WPR25LA095 ## Probable cause The pilot’s failure to secure the coolant cap during the preflight inspection, which resulted in a total loss of engine power due to overheating and a subsequent forced landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng liquid cooling](https://openairdocs.org/ntsb-findings/01058570): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-findings/01058570/cases.md?model=0600096), [All aircraft, 17 cases](https://openairdocs.org/ntsb-findings/01058570/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=0600096), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Engine (reciprocating): recip eng liquid cooling](https://openairdocs.org/ntsb-findings/01058570): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-findings/01058570/cases.md?model=0600096), [All aircraft, 17 cases](https://openairdocs.org/ntsb-findings/01058570/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=0600096), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=0600096), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Quicksilver Aeronautics L-S2S, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=0600096), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis During cruise flight, the pilot reported that he noticed a temperature alarm, and a short time later, the engine sustained a complete loss of power. The pilot initiated a forced landing to a dirt road located in a vineyard. During the landing roll, the airplane veered to the right and struck a pole, which resulted in substantial damage to the right wing. A postaccident inspection of the aircraft revealed a missing cooling system expansion tank cap and a low coolant level. The piston faces also showed high heat signatures from red discoloration and scoring along the cylinder walls. The pilot reported that he removed the cooling system tank cap during the preflight inspection to check the water level and did not re-secure it. During the flight, the engine likely lost cooling fluid and overheated, which resulted in a complete loss of engine power. ## Aircraft - Registration: [N14QK](https://openairdocs.org/aircraft/N14QK), registered now, S/N 10003, built 2014 (OpenAirDocs) - Reported make and model: QUICKSILVER AERONAUTICS LLC L-S2S - Registry model: [Quicksilver Aeronautics L-S2S](https://openairdocs.org/model/quicksilver-aeronautics-l-s2s) (registry code 0600096) (OpenAirDocs) - Registry engine: [Rotax 582UL](https://openairdocs.org/engine/rotax-582ul) (registry code 55558, 2 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 10003 - Year built: 2014 - Airframe hours: 450 - Engines: Rotax 582 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Special light-sport (Special) - Last inspection: Annual, November 15, 2024, 50 hours before - Departed: O60, CLOVERDALE, CA - Equipment: Electronic primary flight display, ADS-B, Airframe parachute ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 76; injuries: none; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, without waivers/limitations; last flight review July 3, 2023; seat: left; restraint: 4-point; flight hours: 990 total, 630 in this make and model, 981 as pilot in command, 4 in the last 90 days, 1.2 in the last 30 days, 1.2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 43 °F - Altimeter: 30.10 inHg - Observed at: KSTS, 13 nm away - METAR: KSTS 172153Z COR 34011KT 10SM SCT035 16/06 A3010 RMK AO2 SLP187 T01560056 ## 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 20250217001759A](https://openairdocs.org/incident/20250217001759A), Feb 17, 2025: Quicksilver Aeronautics LLC L-S2S, Geyersville, CA, Substantial damage. Pilot attested to removing radiator cap to top off coolant and failing to replace cap prior to takeoff. Engine overheated and pilot made emergency landing on… ## Docket (3 files) The files NTSB released with the investigation on May 12, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=199721. 6.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18583800&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photos (item 2, PDF, 3 pages, 2 photos, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18598001&FileExtension=pdf&FileName=Photos-Rel.pdf - Email correspondence with pilot (item 3, PDF, 3 pages, 2 photos, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18642539&FileExtension=pdf&FileName=EMAIL_Redacted-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.