Quicksilver Aeronautics LLC L-S2S accident near Geyserville, California, February 17, 2025
On February 17, 2025 at about 8:20 pm local time, a 2014 Quicksilver Aeronautics LLC L-S2S, registered N14QK, was substantially damaged in an accident during enroute (cruise) near Geyserville, California. It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 17, 2025 · about 8:20 pm local time
- Place
- Geyserville, California · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Quicksilver Aeronautics LLC L-S2S, built 2014 · all L-S2Ss on the register
- Registration
- N14QK · registry record · serial 10003
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (total) during enroute (cruise) defining event
- Off-field or emergency landing during landing
- Collision during takeoff/land during landing (landing roll)
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng liquid cooling › Incorrect service/maintenance
- Personnel issues › Task performance › Inspection › Preflight inspection › Pilot
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng liquid cooling › Malfunction
Pilot
- Certificate: private
- Ratings: single-engine land; single-engine sea; instructor: sport pilot
- Flight time: 990 hours in all; 630 in this make and model; 4 in the last 90 days; 1.2 in the last 30 days; 981 as pilot in command; 278 on instruments
- Last flight review: July 3, 2023
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Passenger
- Seat: rgt
The aircraft
- Airframe total time: 450 hours
- Last inspection: annual inspection, November 15, 2024; 50 hours since
- Maximum gross weight: 1,000 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 582 (piston); 120 hours total
The flight
- Departed from: O60 Cloverdale CA at 7:30 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 340° at 11 knots
- Visibility: 10 statute miles
- Sky: scat at 3,500 ft
- Temperature: 61°F (16°C), dew point 43°F (6°C)
- Altimeter: 30.10 inHg
- Observation at 1:53 pm from KSTS, 13 miles away
Weather report (METAR): KSTS 172153Z COR 34011KT 10SM SCT035 16/06 A3010 RMK AO2 SLP187 T01560056
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on May 12, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 10 pages | View Download |
| 2 | Photos | PDF, 3 pages | View Download |
| 3 | Email Correspondence with Pilot | PDF, 3 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR25LA095.