WPR15FA140 · Quicksilver Enterprises Inc MXL II
Quicksilver Enterprises Inc MXL II · Accident: loss of control in flight while maneuvering
From Petaluma Municipal Airport (O69) to Petaluma Municipal Airport (O69)
Event
- NTSB case
- WPR15FA140
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Quicksilver Enterprises Inc MXL II
- Aircraft type
- Quicksilver Enterprises MXL
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N476VB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Petaluma Municipal Airport (O69), Petaluma, CATo Petaluma Municipal Airport (O69), Petaluma, CA
- Aircraft age
- About 31 years (built 1984)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control in flight
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Aircraft › Aircraft oper/perf/capability
- Aircraft › Aircraft structures
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The student pilot was conducting a local area flight in daytime visual meteorological conditions. Multiple witnesses located near the accident site reported observing the airplane maneuvering over the area. Two witnesses reported seeing the airplane in a steep descent with the wings folded upward before it impacted the ground.
Postaccident examination of the accident site and the airplane revealed signatures consistent with a high-speed, near-vertical impact with terrain. No evidence was found of any preexisting mechanical anomalies that would have precluded normal operation of the airplane.
It's likely that while maneuvering, the pilot lost control of the airplane, which resulted in a steep descent from which the pilot did not recover. During the vertical descent, the airplane's structural capabilities were exceeded, and the wing spars failed in overstress. The pilot had applied for a medical certificate in 2003 and 2004: however, he did not provide all the information requested by the Federal Aviation Administration (FAA), and his application was denied. Review of FAA medical records revealed that the pilot had a history of a traumatic brain injury; however, based on a review of the information that the pilot provided in 2004, it is unlikely that the long term effects from the pilot's traumatic brain injury contributed to the accident.
Postaccident toxicology testing identified tetrahydrocannabinol (THC), the psychoactive component in marijuana, in the pilot's blood and various tissues, and diphenhydramine, an over-the-counter allergy and sleep aid medication, in the pilot's blood The levels of THC found in tissues suggested that it was not used recently. Therefore, it is unlikely that the pilot's use of marijuana caused impairment or contributed to the accident. However, the level of diphenhydramine found suggested that, at the time of the accident, the pilot was likely impaired by his use of diphenhydramine.
Probable cause
The pilot's failure to maintain control of the airplane while maneuvering, which resulted in an uncontrolled descent and structural failure. Contributing to the accident was the pilot's impairment from his use of diphenhydramine.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR15FA140
- Event ID
- 20150403X34847
- Case number
- WPR15FA140
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 9cf8723dabf00cc506c01997c047ccefdae4d5e9565e35d86595d3e271e97c12; retrieved 2026-09-14T17:34:33.331Z.