Kolb Company TWINSTAR accident near Halfmoon Bay, California, March 25, 1990
On March 25, 1990 at about 9:15 pm local time, a Kolb Company TWINSTAR, an amateur-built aircraft,, registered N287PH, was substantially damaged in an accident near Halfmoon Bay, 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
FAILURE OF THE PILOT TO MAINTAIN ADEQUATE AIRSPEED AND ALTITUDE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 25, 1990 · about 9:15 pm local time
- Place
- Halfmoon Bay, California · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Kolb Company TWINSTAR, amateur-built
- Registration
- N287PH · no longer on the register · serial 0019
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT STATED HE WAS DESCENDING IN A 270 DEGREE RIGHT TURN TO LAND ON TOP OF A HILL WHEN HE LET HIS AIRSPEED DROP TOO MUCH. THE AIRCRAFT COLLIDED WITH THE HILL ON THE UPSLOPE SIDE. THE AIRCRAFT HAD NO REGISTRATION OR AIRWORTHINESS CERTIFICATE. THERE WAS FUEL ON BOARD AT THE TIME AND EVIDENCE INDICATED THE ENGINE WAS OPERATING BEFORE THE ACCIDENT.
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: private
- Ratings: single-engine land
- Flight time: 234 hours in all; 54 in this make and model; 8 in the last 90 days; 8 in the last 30 days; 203 as pilot in command
- Medical certificate: None
- Seat: left
The aircraft
- Airframe total time: 54 hours
- Last inspection: inspection type not recorded
- Maximum gross weight: 750 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 503 (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 330° at 9 knots, gusting 12
- Visibility: 20 statute miles
- Sky: broken clouds at 1,200 ft; not recorded
- Temperature: 50°F (10°C), dew point 0°F (-18°C)
- Observation at 1:00 pm
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.