Mechanical problem may have caused seaplane crash off Whidbey Island

There are indications that a mechanical problem caused a float plane to crash off Whidbey Island last month.

The crash happened on Sept. 4 about a half hour into a flight from Friday Harbor to Renton. The accident killed all ten people on board. So far, six bodies have been recovered.

Victims of floatplane crash included activist, winemaker

The National Transportation Safety Board (NTSB) released an update Monday that concluded the horizontal stabilizer actuator had separated into two pieces.

The stabilizer is the device in the tail that helps the pilot control the plane.

The report said it appeared the part became unscrewed and the ring, used to lock it in place, was not found in the wreckage. The NTSB says that it is possible for the ring to be partially installed.

The NTSB does not know whether the lock ring was installed before the plane hit the water.

“The NTSB, in coordination with the Transportation Safety Board of Canada, has asked that the manufacturer draft instructions for an inspection of the actuator to ensure that the lock ring is in place and properly engaged to prevent unthreading of the clamp nut,” the report read.

Witnesses said they saw the plane nose dive into Mutiny Bay. The plane, a de Havilland Canada DHC-3 Otter turboprop, was operated by Friday Harbor Seaplanes.

KIRO Newsradio’s Heather Bosch contributed to this report. Check back for updates.