The plane is under approximately 190 feet of water. The NTSB plans to use a remotely operated vehicle to help recover the wreckage.
ISLAND COUNTY, Wash. — The National Transportation Safety Board (NTSB) located the wreckage of a seaplane that crashed into Puget Sound near Whidbey Island in early September.
The seaplane was flying from Friday Harbor to Renton Municipal Airport on Sunday, September 4 when reports indicate it nosedived and crashed into Mutiny Bay. All nine passengers on board and the pilot were killed.
The plane is under approximately 190 feet of water, according to an update of the NTSB. Due to the depth and speed of the current, which is three to five knots, the agency decided that the best way to recover the wreckage is by using a remotely operated vehicle (ROV).
The National Oceanic and Atmospheric Administration (NOAA) and the University of Washington Applied Physics Laboratory helped capture images using side-scan sonar and 3D instruments. The instruments are in a multi-sensor trailer, which the lab calls MuST.
MuST is normally used to study what is under the sand. The Applied Physics Laboratory was asked to use the machine to scan the depths of Mutiny Bay, director Kevin Williams said. MuST was placed 160 under water.
“We could fly it about 30 feet above the bottom and then use a lot of the same sonar that NOAA would use, but we get it close to all objects,” Williams said.
NOAA is working with local businesses and federal agencies to obtain an ROV to recover the seaplane, which is well suited to operating in deep water.
“Its operating depth is mostly based on its design specification. The one we use is rated at 3,000 meters, which is about 10,000 feet,” said Chuck McGuire of the Applied Physics Laboratory.
However, retrieving the seaplane with an ROV could still be challenging considering the current under the water.
“As the water is emptied from the structure, there’s a lot of weight inside. If you move too fast, you can end up ripping off the wings or displacing the cargo or the plane could break loose and fall back to the bottom.” MacGuire said.
Some items were recovered from the plane, according to the NTSB, including foam fragments from the plane’s floats, a seat cushion, a seat belt, dispatch documents, debris from the floor structure and some personal items from the victims.
The plane is a de Havilland DHC-3 Otter seaplane that was built in 1967.
Federal Aviation Administration (FAA) records show that the plane received a airworthiness certificate in May 2014, which probably means the plane’s owner, Northwest Seaplanesinstalled a new turboprop engine.
A Facebook post of Northwest Seaplanes states that Otter received an annual maintenance check.
Seaplane companies are heavily regulated by the FAA, according to former NTSB Senior Air Safety Investigator Gregory Feith. It is a regulatory level just below commercial airlines.
Seaplane Northwest is a sister company of Friday Harbor Seaplanes. Feith said he knows of no violations in the company’s history.