Preparations for retrieving the wreckage of the Ground Self-Defense Force helicopter that crashed off the Okinawa Prefecture island of Miyako could start before the end of this month, but the depth of the sea at the site and the seabed's complex topography are expected to make for a challenging recovery operation.
Thursday marked two weeks since the UH-60JA multipurpose helicopter disappeared from radar near Miyako with 10 personnel aboard, including the head of the GSDF's 8th Division. No survivors have been found.
The extent of the damage to the crashed aircraft has astonished those involved in the rescue operation.
"Is that really a helicopter?" a government official reportedly wondered while examining an image of the distorted wreckage on the seafloor captured by an underwater camera.
Lighting illuminated what appeared to be a broken part of the aircraft's fuselage, sitting at a depth where natural light could not reach. "The only certain thing was that the helicopter had no trace of its original form," the official said.
Floating objects recovered from the scene also indicated the helicopter suffered a fierce impact.
At least 20 parts apparently from the helicopter have been found, including a cover for the radar located near the chopper's nose, a section of a door and a rotor blade.
"It seems the aircraft violently struck the sea surface without having time to attempt an emergency landing," a senior Defense Ministry official said.
The helicopter sank to the bottom about six kilometers north of Irabu Island, which neighbors Miyako Island. Five bodies assumed to be personnel were found inside the fuselage. Another has been spotted but has not been recovered.
The retrieval of the wreckage will be contracted out to private companies, including a salvage firm. The GSDF on Sunday made an official notice for bids on the search and recovery operations, and tenders are to be submitted on Friday, when the winners will be selected. The salvage operation is to end June 30.
Challenges abound in bringing the aircraft back to the surface. The helicopter was found on the seafloor at a depth of 106 meters, which is too deep for divers to operate except through a special method called saturation diving. The seabed also has a sharp dropoff.
"The retrieval operation must be conducted very carefully," warned Atsushi Toyama, a former head of the 3rd Regional Coast Guard Headquarters.
According to Toyama, the operation could involve sliding straps beneath the helicopter and applying hooks to the aircraft's frame, or encasing the wreckage in a wire net.
Further complicating matters is that a helicopter does not have the structural strength of a boat, so there are concerns that water resistance while it is being lifted could cause additional damage.
A tributary of the Kuroshio current flows between the islands in the area, and is fast and complex. At times, the current may flow in a different direction on the seabed than it does at the surface.
"This won't be a straightforward operation," Toyama said.
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