# Accident 20240114000509A: Ostroth Thane L COZY MK IV, Half Moon Bay, CA, January 14, 2024

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: January 14, 2024, 19:13 local time
- Place: Half Moon Bay, CA
- Airport: Half Moon Bay
- Damage: Destroyed
- Phase of flight: Takeoff: Climb Out
- Operating rules: General operating rules (Part 91)
- Location: 37.5018° N, 122.5105° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=37.5018&lon=-122.5105&mi=10
- Aircraft: N656TE, registered now (https://openairdocs.org/aircraft/N656TE) (OpenAirDocs)
- Registry model: Ostroth Thane L COZY MK IV (registry code 056241N, https://openairdocs.org/model/ostroth-thane-l-cozy-mk-iv) (OpenAirDocs)
- Registry engine: Superior IO-360 series (registry code 59251, https://openairdocs.org/engine/superior-io-360-series) (OpenAirDocs)
- Reported make and model: OSTROTH THANE L COZY MK IV
- Reported engine: SUPERIOR IO-360 SER
- People aboard: 4
- Fatal injuries: 4
- Other injuries: 0
- Pilot certificates: Commercial pilot, flight instructor
- Pilot flight hours: 2,440 total, 210 in this make and model, 75 in the last 90 days
- NTSB investigation: [NTSB WPR24FA073](https://openairdocs.org/ntsb/WPR24FA073) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20240114000509A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

^PRIVACY DATA OMITTED^, COZY MK4, CRASHED OFF THE COAST OF HALF MOON BAY, CA AT APPROXIMATELY 1934 PST.  THE SAN MATEO SHERIFF STATED THE FLOATING WRECKAGE DEBRIS WAS LOCATED 100 YARDS OFFSHORE, AND ABOUT 300 YARDS SOUTH OF MOSS BEACH.   THE AIRCRAFT WAS DESTROYED AND HAD ONE PILOT AND 3 PASSENGERS THAT WERE FATALLY INJURED. THE CENTER PORTION OF THE FUSELAGE, VARIOUS FIBERGLASS PIECES, ENGINE, AND PROPELLER WASHED UP ON SHORE.

THE CENTER PORTION OF THE FUSELAGE WAS FOUND UPSIDE DOWN IN THE SAND.  THE NOSE SECTION WAS BROKEN OFF WHICH CONTAINED THE NOSE GEAR.  THE MAIN WHEELS WERE SHEARED OFF.  A FRAGMENTED SECTION OF THE RIGHT WING WAS STILL ATTACHED TO THE FUSELAGE.  THIS PORTION OF THE RIGHT WING STILL HAD PIECE OF THE VERTICAL RUDDER ATTACHED.  FUEL CAPS WERE IN PLACE AND SECURED.  FLIPPED FUSELAGE INTO VERTICAL POSITION, THREE OF THE FOUR SEATBELTS WERE STILL BUCKLED.  MOST OF THE INSTRUMENT PANEL AND AVIONICS WERE MISSING.

THE ENGINE AND ATTACHED PROP WERE WITH THE FUSELAGE.  THE ENGINE MOTOR MOUNT WAS BROKEN BUT THE MOUNT PORTIONS WERE STILL CONNECTED TO THE FUSELAGE AND ENGINE.  ENGINE CONTROL CABLES WERE STILL CONNECTED.  THE ENGINE WAS FOUND IN THE SAND UPSIDE DOWN LIKE THE FUSELAGE.  INITIAL EXAMINATION OF THE ENGINE WITH THE NTSB DID NOT REVEAL ANY PRE ACCIDENT DAMAGE.  ASSISTED NTSB INVESTIGATOR AND REMOVED THE FUEL FLOW DIVIDER AT HIS DIRECTION.  THE FUEL INLET AND 4 FUEL OUTLET FITTINGS WERE NOT TIGHT.  DUE TO THE SALT AND SAND DEBRIS, I USED A WRENCH TO LOOSEN THE FITTINGS WITH LITTLE EFFORT.  THERE WAS AN ODOR OF FUEL PRESENT.

WITNESS STATED THEY HEARD THE ENGINE SPUTTERING AND AIRCRAFT APPEARED TO BE “DIPPING” AND “TURNING”.  ONE WITNESS DESCRIBED THE ENGINE SOUND AS “COUGHING”.  WITNESS DESCRIBED THE AIRPLANE PICKED UP SPEED AS THEY WATCHED IT AND HEARD THE ENGINE CUT OUT, BANKED IN, BUT LOST VISUAL SIGHT OF THE AIRPLANE’S LIGHTS.

THERE WAS NO DISTRESS CALL MADE.  ADS-B DATA NEVER SHOWED ALTITUDE EXCEEDED 250 FEET.  REPORTED WEATHER AT THE TIME WAS REPORTED 300 FEET BROKEN WITH MIST.

ENGINE EXAMINANATION SCHEDULED.  THIS REPORT WILL BE UPDATED IF ANY RELEVANT INFORMATION IS DISCOVERED.

## The NTSB's investigation of this event (1)

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.

- [NTSB WPR24FA073](https://openairdocs.org/ntsb/WPR24FA073), Jan 15, 2024: Ostroth Thane L Cozy MK IV (N656TE), Half Moon Bay, CA, destroyed, 4 fatal. Probable cause: The airplane’s impact with the ocean for undetermined reasons after departing into night, instrument meteorological conditions.

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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