Accident de Havilland Canada DHC-3T Turbine Otter N725TH, Sunday 4 September 2022
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Date:Sunday 4 September 2022
Time:15:09
Type:Silhouette image of generic DH3T model; specific model in this crash may look slightly different    
de Havilland Canada DHC-3T Turbine Otter
Owner/operator:Friday Harbor Seaplane Tours
Registration: N725TH
MSN: 466
Year of manufacture:1967
Total airframe hrs:24430 hours
Engine model:General Electric H80-200
Fatalities:Fatalities: 10 / Occupants: 10
Other fatalities:0
Aircraft damage: Destroyed, written off
Category:Accident
Location:3 km SW off Freeland, WA -   United States of America
Phase: En route
Nature:Passenger - Non-Scheduled/charter/Air Taxi
Departure airport:Friday Harbor SPB, WA (FBS)
Destination airport:Renton Airport, WA (RNT/KRNT)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
A float-equipped de Havilland Canada DHC-3T Turbine Otter, N725TH, was destroyed when it impacted the water in Mutiny Bay, Washington. All ten occupants were killed in the accident.

The accident flight departed from Friday Harbor Seaplane Base, Washington, about 14:50 with a destination of Renton-Will Rogers Wiley Post Memorial Seaplane Base, Washington. Track data indicated the airplane flew at an en route altitude of 650 to 975 ft above mean sea level (msl), and the groundspeed was between 115 and 125 knots.
At 15:08:43, the airplane pitched up about 8° and then abruptly pitched down about 58°. The data ended at 15:08:51, when the airplane’s altitude was 600 ft msl and the estimated descent rate was more than 9,500 ft per minute.

Witnesses near the accident site reported that the airplane was in level flight before it entered a slight climb, then pitched down in a near-vertical descent. The airplane continued in a nose low, spiraling, near-vertical descent until it impacted water in Mutiny Bay.

The wreckage was located a week later, at a depth of 190 feet.

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.

Accident investigation:
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Investigating agency: NTSB
Report number: DCA22MA193
Status: Investigation completed
Duration: 1 year 1 month
Download report: Final report

Sources:

AP
Photo
NTSB

Statistics

  • 12th worst accident in 2022
  • worst accident of this aircraft type
  • worst accident of this aircraft type at the time

Location

Revision history:

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