NHK has learned that the search for two Maritime Self-Defense Force helicopters that crashed into the Pacific in April will start next month. An unmanned deep-sea vehicle that can dive at a depth of up to 6,000 meters will be used.
Sources have told NHK that the Japan Agency for Marine-Earth Science and Technology, or JAMSTEC, will begin the search as early as the start of July, at the request of Japan's Defense Ministry.
Two MSDF helicopters collided and crashed into waters off Torishima Island in the Izu Islands during nighttime training on April 20. Of the eight crew members on board, one was confirmed dead shortly after. The MSDF declared the seven other members dead on Tuesday.
Flight recorders from both helicopters and pieces of the aircraft have been retrieved. But their main parts are believed to be lying on the seabed at a depth of about 5,500 meters.
Sources say that JAMSTEC will use Deep Tow, a deep ocean floor survey system equipped with sonar and cameras, to search a wide area of the ocean floor.
Deep Tow has often been used in underwater searches in past accidents.
Following the collision between a MSDF Aegis vessel and a fishing boat in 2008, Deep Tow discovered parts of the sunken fishing boat at a depth of over 1,800 meters.
In 1999, it found an engine of an H2 rocket, which crashed into the sea after a failed launch, in waters about 3,000 meters deep off the Ogasawara Islands.