SEATTLE (AP) — Federal regulators on Wednesday ordered seaplanes like one that went down in Washington's Puget Sound in September be inspected for a flaw that likely caused the deadly crash.
The Federal Aviation Administration airworthiness directive requires that operators of all the DHC-3 Otter seaplanes in the United States — 63 of about 160 operating worldwide — examine the stabilizer to confirm the condition of an actuator piece, The Seattle Times reported. That piece was missing from the Friday Harbor Seaplanes aircraft that crashed Sept. 4 into the waters near Whidbey Island, killing 10 people, newspaper reported.
Operators must confirm that the stabilizer actuator lock ring is correctly installed and report back to the FAA by Dec. 19, according to the directive. The order does not ground the aircraft.
Kenmore Air, the largest Otter operator on Puget Sound, has said its aircraft have passed inspection.
On Oct. 24, the National Transportation Safety Board, which is investigating the crash, urged operators to ground all those particular planes until the part is inspected, noting it would be up to the FAA to issue a grounding order. Last week, the NTSB officially called for the FAA to require inspection of the planes.
"We're concerned that another plane could crash as a result of something similar," NTSB Chair Jennifer Homendy said at the time.
In an investigative update, the NTSB identified a lock missing from the actuator of the horizontal tail — also known as a stabilizer — which controls the pitch of the plane.
After crews recovered about 85% of the plane wreckage in September, investigators found the upper portion of the actuator was attached to the horizontal stabilizer, while the lower part was "attached to its mount in the fuselage" but disconnected.
While the NTSB has not officially said the actuator separation caused the crash, Homendy said the failure of the actuator could have caused the plane to plummet. Additional crashes could happen if the lock pin is missing or improperly installed.
An FAA spokesperson told The Seattle Times on Wednesday that the directive was issued after the manufacturer, Viking Air Limited, issued a service bulletin.
A problem with pitch control would be consistent with the "nose dive" reported by people who saw the plane hit Puget Sound.
Witnesses helped officials identify the crash site, search for survivors and locate the remains of one passenger.
It took the NTSB and U.S. Navy crews more than a week and several types of sonar to find what remained of the plane because of the depth and current of the channel where the aircraft hit. Remains of seven of the 10 people aboard have been located.