Amateur-built SCORPION 133 accident near Boonville, California, September 27, 1987
On September 27, 1987 at about 5:00 pm local time, a amateur-built SCORPION 133 (helicopter), registered N25059, was destroyed in an accident near Boonville, California. It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 27, 1987 · about 5:00 pm local time
- Place
- Boonville, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built SCORPION 133 SCORPION 1
- Registration
- N25059 · registry record · serial S1331357
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PLT SAID THAT WHEN HE WAS PRACTICING QUICK STOPS & FLARES, THE TAIL ROTOR STRUCK THE GROUND. THE HELICOPTER THEN YAWED, TOUCHED DOWN (RIGHT SKID 1ST) & ROLLED OVER. NO PREIMPACT MECHANICAL FAILURE OR MALFUNCTION WAS RPRTD.
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: student
- Flight time: 79 hours in all; 66 in this make and model; 10 in the last 90 days; 10 in the last 30 days; 53 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 245 hours
- Last inspection: 100-hour inspection, July 10, 1987; 37 hours since
- Maximum gross weight: 1,230 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotorway RW-133 (piston); 0 hours total
The flight
- Departed from: Palmer Ranch CA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Visibility: 15 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 48°F (9°C)
- Altimeter: 30.00 inHg
- Observation at 4:46 pm from UKI
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.