NTSB Finds Severe Flaws With Floatplane During Crash Investigation

The National Transportation Safety Board said they found notable flaws with the floatplane involved in the deadly Puget Sound, according to KING 5.

Investigators announced they didn't find a lock ring installed to a part that controls pitch on the DHC-3 Turbine Otter, which may have led to a loss of control in the air. According to the manufacturer's assembly drawings for the horizontal actuator, a hole must be drilled into the clamp nut to accept the lock, officials said.

The tragic accident revealed five drilled holes into the clamp nut threads, and three of the holes were damaged, NTSB found. This means the lock ring could only be partially inserted at best.

Officials said the actuator keeps the stabilizer in place. If the nut and barrel unthread during a flight, the stabilizer would rotate "uncontrollably" and result in a possible loss of airplane control, according to the agency.

The plane was traveling from Friday Harbor to Renton Municipal Airport on September 4 when it crashed into Mutiny Bay off Whidbey Island, nearly 30 miles northwest of Seattle. Everyone onboard was killed, including a child. Some of the victims' bodies have been recovered.

Officials confirmed they didn't find the lock ring during the floatplane wreckage's examination or recovery process. Crews recovered nearly 85% of the floatplane from the bottom of the sea on September 30.

NTSB is also looking into Northwest Seaplanes, the Renton-based company that owned the plane, and their maintenance records in light of their recent findings, according to an agency spokesperson.

"There's still a lot of work to do, but this certainly narrows down the focus of the investigation," they said.