# Accident 20220904020609A: Dehavilland DHC-3, Mutiny Bay, WA, September 4, 2022

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: September 4, 2022, 15:09 local time
- Place: Mutiny Bay, WA
- Damage: Destroyed
- Phase of flight: Cruise/Level Flight
- Operating rules: Air taxi and commuter (Part 135)
- Operator: HUFA
- Location: 47.9903° N, 122.5850° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=47.9903&lon=-122.5850&mi=10
- Aircraft: N725TH, a cancelled registration (https://openairdocs.org/deregistered/N725TH-2024-03-25) (OpenAirDocs)
- Registry model: Dehavilland DHC-3 (registry code 2802412, https://openairdocs.org/model/dehavilland-dhc-3) (OpenAirDocs)
- Registry engine: Walter M601 series (registry code 64003, https://openairdocs.org/engine/walter-m601-series) (OpenAirDocs)
- Reported make and model: DEHAVILLAND DHC-3
- Reported engine: WALTER M601 SER
- People aboard: 10
- Fatal injuries: 10
- Other injuries: 0
- NTSB investigation: [NTSB DCA22MA193](https://openairdocs.org/ntsb/DCA22MA193) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20220904020609A

## Narrative

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

DURING THE EXAMINATION OF THE AIRPLANE WRECKAGE, THE INVESTIGATIVE TEAM FOUND THAT THE CLAMP NUT THAT ATTACHES THE TOP EYE END AND BEARING ASSEMBLY OF THE HORIZONTAL STABILIZER ACTUATOR TO THE ACTUATOR BARREL (JACK TRIM) HAD UNSCREWED FROM THE BARREL. THE EXAMINATION ALSO FOUND THAT THE CIRCULAR WIRE LOCK RING, WHICH WAS DESIGNED TO PREVENT THE CLAMP NUT FROM UNSCREWING, WAS NOT PRESENT. IF THE ACTUATOR BARREL AND THE CLAMP NUT ARE NOT SECURED TOGETHER AND BECOME SEPARATED, THE ACTUATOR WOULD NOT BE ABLE TO CONTROL THE POSITION OF THE HORIZONTAL STABILIZER, RESULTING IN A REDUCTION OR LOSS OF PITCH CONTROL.

## 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 DCA22MA193](https://openairdocs.org/ntsb/DCA22MA193), Sep 4, 2022: Dehavilland DHC-3 (N725TH), Freeland, WA, destroyed, 10 fatal. Probable cause: The in-flight unthreading of the clamp nut from the horizontal stabilizer trim actuator barrel due to a missing lock ring, which resulted in the horizontal stabilizer moving to an extreme…

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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