Amateur-built Cavalon accident near Upper Lake, California, August 4, 2020
On August 4, 2020 at about 4:30 pm local time, a 2017 amateur-built Cavalon (gyroplane), registered N635BC, was substantially damaged in an accident during maneuvering (low-alt flying) near Upper Lake, California. It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s distraction and failure to maintain adequate airspeed during a low altitude maneuver, which resulted in a loss of aircraft control and collision with terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 4, 2020 · about 4:30 pm local time
- Place
- Upper Lake, California · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Cavalon, built 2017
- Registration
- N635BC · no longer on the register · serial VO0320
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the gyroplane reported that, while maneuvering at low altitude over a friend’s property, he looked down and backwards to the ground and inadvertently pulled back on the control stick, slowing the gyroplane to about 20 mph. He attempted to correct by applying full engine power and descending to reestablish airspeed. Concerned the gyroplane would impact trees, he flared just above a wooded area. The gyroplane fell through the trees to the ground substantially damaging the tail section. The pilot reported that there were no preaccident mechanical failures or malfunctions with the gyroplane that would have precluded normal operation.
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
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
- Low altitude operation/event during maneuvering (low-alt flying) defining event
The NTSB's findings
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Not attained/maintained
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Personnel issues › Psychological › Attention/monitoring › Task monitoring/vigilance › Pilot
Pilot
- Certificate: sport pilot
- Ratings: single-engine land; rotorcraft: gyroplane
- Flight time: 853.8 hours in all; 71.8 in this make and model; 71.3 in the last 90 days; 24.8 in the last 30 days; 803.3 as pilot in command
- Medical certificate: None
- Seat: rgt
- Injury: serious injuries
Passenger
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 272 hours
- Last inspection: annual inspection, January 15, 2020
- Maximum gross weight: 1,234 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 914 UL (piston); 272 hours total
The flight
- Departed from: 1O2 Lakeport CA at 3:30 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 50 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 54°F (12°C)
- Altimeter: 29.99 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on July 14, 2021. 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, 9 pages | View Download |
| 2 | Photos | PDF, 7 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.