Amateur-built SCORPION 133 accident near Oroville, California, July 25, 1990
On July 25, 1990 at about 4:10 am local time, a amateur-built SCORPION 133 (helicopter), registered N4639E, was substantially damaged in an accident near Oroville, California. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S LOSS OF DIRECTIONAL CONTROL.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 25, 1990 · about 4:10 am local time
- Place
- Oroville, California · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SCORPION 133 SCORPION 1
- Registration
- N4639E · no longer on the register · serial 1246
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
A HELICOPTER COLLIDED WITH THE GROUND WHILE THE PILOT WAS ATTEMPTING TO HOVER.
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
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 1,000 hours in all; 6 in this make and model
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 220 hours
- Last inspection: annual inspection, April 18, 1990; 6 hours since
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway RW-1 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 40 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
- Observation at 3:15 am from RBL, 55 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.