Wreckage from a floatplane crash in Mutiny Bay over Labor Day weekend will likely be recovered later this month, according to the National Transportation Safety Board.
The NTSB released a preliminary report Friday describing details of the flight and plane, but stopped short of naming any potential cause of the crash, in which a seasoned pilot and nine passengers were killed in a sudden, puzzling plummet into Puget Sound. The plane had undergone a 100-hour inspection — a routine examination done every 100 flight hours — just three days before the incident.
In the immediate aftermath, only small pieces of debris, some personal items and one body, identified as 29-year-old Gabby Hanna, were recovered from the deadly Sept. 4 crash. Witnesses said the plane disappeared into the water.
The NTSB announced Friday that it had secured the required work-class remote operated vehicles to begin recovering wreckage over 150 feet below the surface last weekend. Those recovery efforts are set to begin Sept. 26, more than three weeks after the crash.
According to the release, the U.S. Navy will use a Deep Drone 8000 ROV, a barge and a crane to recover the wreckage from the seafloor. Crews will work on recovery 24/7 once the equipment is in place, until any located wreckage is removed.
In Friday’s report, based largely on witness reports because of a lack of physical evidence, the NTSB noted “substantial” impact to the plane took place after a “near-vertical” nose dive into Puget Sound, just off Whidbey Island.
In the report, 911 calls and interviews after the crash, witnesses described the airplane as spinning on the way down and one reported hearing engine noise without any “pitch change” during the descent.
The plane most recently received 100-hour inspections on Aug. 16 and Sept. 1. During the September inspection, a left-hand rudder retract cable was replaced. In August, the horizontal stabilizer hinge bolts, a right-hand engine igniter and a left-hand float locker latch were replaced, according to the report.
In August and September, inspections were completed of the control column lower assembly and elevator control tabs, as required by Federal Aviation Administration airworthiness directives.
The FAA established an airworthiness directive for the elevator control tabs — small hinge mechanisms that contribute to the plane’s elevator system, which helps a pilot control the plane’s pitch, or the vertical movement of the nose — in 2004, after reports that the control rod to the elevator servo-tab system could detach from the elevator servo tab, causing the servo tab to “flutter” on DHC-3 Turbine Otter floatplanes with a turbine engine installed, like the one in the Mutiny Bay crash.
The fluttering servo tab has been linked to multiple DHC-3 crashes.
Investigators will use additional evidence from the wreckage to conduct the full investigation, which can take up to 24 months. Limited additional data may be available from the plane.
According to NTSB, the plane had a King 560 Enhanced Ground Proximity Warning System installed, which tracks limited parametric flight data, but was not “crash-protected.” It was not equipped “nor was it required to be equipped” with a flight data recorder or cockpit voice recorder, according to the report.