# NTSB LAX90DUK01: Kolb Twinstar, N287PH, Halfmoon Bay, CA, March 25, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Final report
- Date: March 25, 1990, 13:15 local (21:15 UTC)
- Place: Halfmoon Bay, CA
- Coordinates: 37.440937, -122.409873 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.4409&lon=-122.4099&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious
- Status: Completed, report February 12, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 26549
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90DUK01
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26549/pdf
- Page: https://openairdocs.org/ntsb/LAX90DUK01

## Probable cause

FAILURE OF THE PILOT TO MAINTAIN ADEQUATE AIRSPEED AND ALTITUDE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight collision with terrain/water, approach - vfr pattern - base turn
  - proper altitude - not maintained, pilot in command (cause)
  - airspeed - not maintained, pilot in command (cause)

## Analysis

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.

## Aircraft

- Registration: [N287PH](https://openairdocs.org/deregistered/N287PH-2013-09-13), registration cancelled 2013-09-13, S/N 0019 (OpenAirDocs)
- Reported make and model: Kolb Company TWINSTAR
- Registry model: [Huether Philip Michel KOLB TWINSTAR](https://openairdocs.org/model/huether-philip-michel-kolb-twinstar) (registry code 05612NE) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 0019
- Airframe hours: 54
- Engines: ROTAX 503 50 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Phillip M. Huether
- Airworthiness certificate: Special, Experimental (Special)

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 37; private; airplane ratings: single-engine land; seat: left; flight hours: 234 total, 54 in this make and model, 203 as pilot in command, 8 in the last 90 days, 8 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 9 knots, gusting 12
- Visibility: 20 statute miles
- Lowest ceiling: 1,200 ft broken
- Temperature: 50 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900325015829A](https://openairdocs.org/incident/19900325015829A), Mar 25, 1990: Amtrkb TWINSTAR, Half Moon Bay, CA, Substantial damage. Misjudged gusty winds on approach to a hilltop landing. Struck hill short of landing area. No medical or biennial.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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