NTSB Cites Critical Flight Control Failure in Fatal Floatplane Accident

Meg Godlewski

Friday, October 06, 2023 at 01:35 PM ET

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Clamp nut and barrel separation on accident airplane. [Credit: NTSB]

Key Takeaways:

The NTSB concluded that the 2022 Seattle floatplane crash, which killed all 10 occupants, was caused by the in-flight failure of a critical flight control component.
Specifically, the elevator actuator disconnected due to a missing lock ring, leading to the horizontal stabilizer moving to an extreme position and rendering the airplane's pitch uncontrollable.
The investigation highlighted a regulatory gap, as the 1967 aircraft lacked a secondary locking device, a requirement introduced for new designs after 1996 but not for retrofitting existing planes.
As a result, the NTSB issued urgent recommendations for the FAA and Transport Canada to mandate immediate inspections and the installation of secondary retention features on all DHC-3 airplanes to prevent similar single-point failures.

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The National Transportation Safety Board (NTSB) reports that the failure of a single component of a critical flight control is to blame for the deadly crash of a floatplane near Seattle on September 4, 2022. The 1967 de Havilland DHC-3 Turbine Otter went down in Mutiny Bay near Freeland, Washington, killing all 10 on board.

The aircraft was owned by Northwest Seaplanes and the flight operated by West Isle Air, a Part 135 operation. The aircraft was en route between Friday Harbor Seaplane Base (W33) and Renton Municipal Airport (KRNT) at the time of the accident. It was the pilot’s second flight of the day, and the accident occurred approximately 18 minutes into it.