The plane is under about 190 feet of water. The NTSB plans to use a remote-controlled vehicle to salvage the wreckage.
ISLAND COUNTY, Wash. — The National Transportation Safety Board (NTSB) has found 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 it reportedly dived and crashed in Mutiny Bay. All nine passengers on board and the pilot were killed.
According to an update from the NTSB, the plane is under about 190 feet of water. Due to the depth and the speed of the current, which ranges from three to five knots, the agency decided that the best method to recover the wreck is to use a remotely operated vehicle (ROV).
The National Oceanic and Atmospheric Administration (NOAA) and the University of Washington’s Applied Physics Laboratory helped capture images using side-scan sonar and 3D instruments. The instruments are on a multi-sensor towed body, which the laboratory calls MuST.
MuST is typically used to examine what is beneath 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 were able to fly it about 30 feet off the ground and then we used a lot of the same sonar that NOAA would use, but we bring it closer to all objects,” Williams said.
NOAA is working with local companies and federal agencies to obtain a seaplane recovery ROV that is well suited for deep water operations.
“Their operating depth is based primarily on their design specification. The one we’re using is capable of reaching 3,000 meters, which is roughly 10,000 feet,” said Chuck McGuire of the Applied Physics Laboratory.
However, seaplane recovery with an ROV could still be a challenge considering underwater currents.
“When the water is emptied from the structure, that’s a whole lot of weight inside. If you move too fast you could end up snapping off wings or shifting the cargo or the plane could break free and fall back to the ground. ‘ McGuire said.
Some items were recovered from the plane, according to the NTSB, including fragments of foam from the plane’s floats, a seat cushion, a seat belt, shipping documents, remnants of floor coverings, and some of the victims’ personal belongings.
The aircraft is a de Havilland DHC-3 Otter floatplane built in 1967.
Federal Aviation Administration (FAA) records show that the plane received an Airworthiness Certificate in May 2014, which likely means the plane’s owner, Northwest Seaplanes, installed a new turboprop engine.
A Northwest Seaplanes Facebook post says Otter received an annual maintenance review.
Seaplane companies are heavily regulated by the FAA, according to Gregory Feith, the NTSB’s former Senior Air Safety Investigator. It is a level of regulation just below commercial airlines.
Seaplane Northwest is a sister company of Friday Harbor Seaplanes. Feith said he was not aware of any violations in the company’s history.
https://www.king5.com/article/news/local/ntsb-finds-crashed-floatplane-puget-sound-whidbey-island/281-53d582d2-c0b7-450a-a9b6-a27212bcd0f8 Crashed floatplane located off Whidbey Island by NTSB