- Date
- September 4, 2022, 15:09 local (22:09 UTC)
- Place
- Freeland, WA · last ADSB from Soper 1508:51.5 crashed in Mutiny Bay, 1.3 nm from shore of Whidbey Island . Nearest zip code is Freeland, WA
- Injuries
- 10 fatal
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N725THDehavilland DHC-3
- Defining event
- Enroute: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 29, 2023
- Report
- Board-adopted by Notation
- Investigation class
- Class 1
- NTSB office
- Major Investigations Division
- Parties
- Friday Harbor Seaplanes, Viking Air Limited, FAA/AVP, TSB Canada, Northwest Seaplanes
- Safety recommendations
- Yes
- FAA report
- 20220904020609A
- Case key
- 105855
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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.
Findings · 6
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Factual narrative
On 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.
Aircraft
- Registration
- N725TH
- Reported as
- Dehavilland DHC-3
- Category
- Airplane
- Serial number
- 466
- Built
- 1967
- Airframe hours
- 24,430
- Engine
- General Electric H80-200, 777 horsepower, turbo prop
- Damage
- Destroyed
- Flight
- Part 135
- Operator
- West Isle Air, doing business as Friday Harbor Seaplanes
- Registered owner
- Northwest Seaplanes Inc
- Airworthiness certificate
- Standard, Commuter
- Last inspection
- 100 hour · September 1, 2022 · 11 hours before
- Departed
- W33 · Friday Harbor, WA
- Destination
- RNT · Renton, WA
- Flight plan
- Company VFR
- Equipment
- ADS-B
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 43
- Injuries
- Fatal
- Certificate
- Commercial
- Airplane ratings
- Single-engine land, Single-engine sea, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, Without waivers/limitations
- Last flight review
- July 29, 2022
- Seat
- Left
- Toxicology
- Performed
- Flight hours
- 3,686 total · 1,300 in this make and model · 297 in the last 90 days · 111 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 310° at 10 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 9,000 ft broken
- Temperature
- 68 °F, dew point 57 °F
- Altimeter
- 30.02 inHg
- Turbulence
- Unknown
- Observed at
- K0S9, 10 nm away
- METAR
- K0S9 042215Z AUTO 31010KT 10SM FEW040 FEW075 BKN090 20/14 A3002 RMK AO2
Docket · 66
The files NTSB released with the investigation on August 31, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 833 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.