4 Sep 2022: DEHAVILLAND DHC-3 (N725TH) — Friday Harbor Seaplanes — Freeland, WA

10 fatalitiesFreeland, WA, United States

Aircraft registered N725TH
Aircraft registered N725TH. Photo: Steve Barnes / CC BY-SA 2.0, via Wikimedia Commons

A scheduled passenger flight operating in Washington state crashed into the water near Freeland, resulting in the loss of all on board.

What happened

On September 4, 2022, at approximately 15:09 Pacific daylight time, a float-equipped de Havilland DHC-3 Otter, registration N725TH, crashed into the water in Mutiny Bay near Freeland, Washington. The aircraft, operated by West Isle Air as a scheduled Part 135 passenger flight, was traveling from Friday Harbor Seaplane Base (W33) to Will Rogers Wiley Post Memorial Seaplane Base (W36) in Renton, Washington.

At the time of the accident, weather conditions were within visual meteorological limits with a visibility of 10 statute miles and winds from 310 degrees at 10 knots. Following the impact with the water, the aircraft sank. The accident resulted in 10 fatal injuries, involving the pilot and nine passengers.

Probable cause

The accident was caused by the clamp nut unthreading from the horizontal stabilizer trim actuator barrel because a lock ring was missing, which caused the horizontal stabilizer to move to an extreme trailing-edge-down position and made the aircraft's pitch uncontrollable.

Contributing factors

Maintenance personnelManufacturerMalfunctionMaintenance provider