Pilot Debrief

DEHAVILLAND DHC-3 near Freeland, WA — 2022-09-04

Final reportDCA22MA193
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Date
2022-09-04
Location
Freeland, WA, USA
Aircraft
DEHAVILLAND DHC-3
Registration
N725TH
Category
Airplane
Highest injury
Fatal
Fatalities
10

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 trailing-edge-down position rendering the airplane’s pitch uncontrollable.

NTSB narrative

HISTORY OF FLIGHTOn September 4, 2022, about 1509 Pacific daylight time, a float-equipped de Havilland DHC-3 (Otter), N725TH, was destroyed when it impacted the water in Mutiny Bay, near Freeland, Washington, and sank. The pilot and nine passengers were fatally injured. The airplane was owned by Northwest Seaplanes, Inc., and operated as a Title 14 Code of Federal Regulations (CFR) Part 135 scheduled passenger flight by West Isle Air dba Friday Harbor Seaplanes. The flight originated at Friday Harbor Seaplane Base (W33), Friday Harbor, Washington, with an intended destination of Will Rogers Wiley Post Memorial Seaplane Base (W36), Renton, Washington. Visual meteorological conditions prevailed at the time of the accident.

NTSB coding

Evidence available

  • Video
  • ADS-B / radar
  • Photos
  • 66 docket documents
View NTSB final reportView NTSB docket

Docket documentsshowing 50 of 66

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