Skip to main content

Mechanical issue may have caused deadly seaplane crash south of Victoria

Share
Seattle (AP) -

A mechanical issue may have caused the seaplane crash that killed 10 people off an island in Washington state last month, U.S. investigators said Monday.

The National Transportation Safety Board, the agency investigating the Sept. 4 crash off Whidbey Island, said it appeared a critical part that moved the plane's horizontal tail stabilizer came apart, The Seattle Times reported.

That part might have failed because a clamp nut unthreaded and rotated due to a missing or improperly installed lock ring, the investigators found.

The failure of the component, called an actuator, during flight “would result in a free-floating horizontal stabilizer, allowing it to rotate uncontrollably about its hinge, resulting in a possible loss of airplane control,” the NTSB said.

The plane, a de Havilland Canada DHC-3 Otter turboprop operated by Renton-based Friday Harbor Seaplanes, crashed into Puget Sound, killing the pilot and all nine passengers. It was about half an hour into a flight to the Seattle suburb of Renton from Friday Harbor, a popular tourist destination in the San Juan Islands.

The investigators said that when the wreckage was retrieved, the upper portion of the actuator was still attached to the horizontal stabilizer while the lower portion was attached to its mount in the fuselage.

The most recent overhaul of the plane's horizontal stabilizer actuator was completed April 21. The lock ring was not found with the wreckage, but several of the holes drilled in the clamp nut to accept the lock ring were damaged “such that they would not allow for the full insertion of the lock ring.”

“At this time, the NTSB does not know whether the lock ring was installed before the airplane impacted the water or why the lock ring was not present during the airplane examination,” the agency said.

The NTSB and the Transportation Safety Board of Canada have asked that the manufacturer draft instructions for all operators of DHC-3 aircraft to inspect the actuator to ensure that the lock ring is properly installed to prevent unthreading of the clamp nut.

Witnesses who saw the plane nose dive into Mutiny Bay helped officials identify the crash site. Still, it took over a week and three types of sonar to locate what remained of the plane due to its depth and the current of the channel where the aircraft hit the water.

Crews using remotely operated vessels and cranes recovered the majority of the plane's wreckage from the sea floor more than 150 feet (46 meters) below the surface in late September.

The victims included a civil rights activist, a business owner, a lawyer, an engineer and the founder of a winery and his family.

Six bodies have been recovered. Those include the body of 29-year-old Gabby Hanna, which was recovered by witnesses the day of the crash, and five others found during recovery efforts.

CTVNews.ca Top Stories

Poilievre suggests Trudeau is too weak to engage with Trump, Ford won't go there

While federal Conservative Leader Pierre Poilievre has taken aim at Prime Minister Justin Trudeau this week, calling him too 'weak' to engage with U.S. president-elect Donald Trump, Ontario Premier Doug Ford declined to echo the characterization in an exclusive Canadian broadcast interview set to air this Sunday on CTV's Question Period.

Why this Toronto man ran so a giant stickman could dance

Colleagues would ask Duncan McCabe if he was training for a marathon, but, really, the 32-year-old accountant was committing multiple hours of his week, for 10 months, to stylistically run on the same few streets in Toronto's west end with absolutely no race in mind. It was all for the sake of creating a seconds-long animation of a dancing stickman for Strava.

Stay Connected