The Bluefin 21 Artemis autonomous underwater vehicle is hoisted back on board the Australian vessel the Ocean Shield after a successful buoyancy test in the southern Indian Ocean. The AUV will likely be deployed as part of the continuing search for the missing Malaysian Airlines Flight MH370. (U.S. navy/Reuters)
More acoustic blips picked up by a sensor towed by a ship off western Australia could finally help silence the conjecture surrounding the missing Malaysia Airlines jet. But triangulating the co-ordinates for Flight MH370’s black box data recorder is just the surface phase of a much deeper mission.
A Towed Pinger Locator used to detect black box recorders sits on the wharf at naval base HMAS Stirling in Perth, Australia. The device has been used on the Australian warship Ocean Shield to aid in the search for missing Malaysia Airlines Flight MH370. (Rob Griffith/Associated Press)
The next challenge would begin thousands of metres below if, as investigators hope, a black box is indeed emitting "pings" from a wreck site on the ocean floor.
"The most reasonable option from there is side-scan sonar," said Jim Gibson, general manager of Phoenix International, which is assisting the U.S. navy on the search for the missing Boeing 777 in the south Indian Ocean.
The sonar technology maps the seabed using soundwave echoes that are digitized into a computer image.
"If you have an untrained eye, you might take a look at something on that sonar trace and say, ‘How can you tell that’s manmade?’ because it looks like a black dot or a rock. But it could be the wing of an airplane," Gibson said.
The above graphic shows the Australian ship Ocean Shield dragging a towed pinger locator, which is used to detect acoustic beacons being sent from a possible black box pinger. (Duk Han Lee/CBC)
Phoenix International, which also helped recover debris from Air France Flight 447 and the Space Shuttle Challenger, has several submersibles at its disposal to find the Malaysian plane, which vanished on March 9 carrying more than 200 people on a flight from Kuala Lumpur to Beijing.
"In this particular case, if — and that's a big if — they find a high probability area, they would in all likelihood use the Artemis," Gibson said.
Search zone as large as L.A.
The yellow, torpedo-shaped Bluefin 21 model of the Artemis AUV (autonomous underwater vehicles) underwent buoyancy testing last week by the Royal Australian Navy’s Ocean Shield ship.
Once deployed, the unmanned Bluefin 21 would have to search a 1,300-square-kilometre swath of ocean floor, an area equivalent to the size of Los Angeles. Covering a search zone that immense could take two months.
The sub takes pictures and has a depth rating of 6,000 metres; the possible black box sending beacons from Flight MH370 is suspected to be about 4,500 metres deep.
The purpose of the pilotless AUVs is to establish a "degree of confidence" as to the location of a debris field, Gibson explained, but the Bluefin 21 would not be able to remove objects and bring them back to the surface.
For the physical extraction phase, a remote-operated vehicle (ROV) resembling a backhoe loading cab with clampers would take the next dive.
A strong candidate to deploy would be Phoenix International’s Remora class of ROV, said Tom Dettweiler, who worked for eight years as a senior project manager for Odyssey Marine Exploration’s shipwrecks team.
'Some of the most fragile things have been brought back like little porcelain statuettes, and they were totally intact.'- Tom Dettweiler, Odyssey Marine Exploration
The Remora was used to inspect the Titanic site in 2001 and was also used to find wreckage from Adam Air Flight 574, a domestic passenger plane that crashed into the Makassar Strait near Indonesia in 2007.
The 900-kilogram ROV is equipped with a heavy-lift system and has video capabilities.
"They have manipulators on the front, which are almost like a mechanical version of a human arm," Dettweiler said. "There are joints, a shoulder, an elbow, a wrist, and some kind of grasper on the end."
A map shows the search area being searched in the hunt for the missing Malaysia Airlines jet. (CBC News)
An operator can move the arm remotely, Dettweiler said. Once the operator watching a screen has the ROV positioned before the black box, he or she can close the gripper from inside the control suite.
"Slowly, so you don’t squash it," Dettweiler said. "In my experience, some of the most fragile things have been brought back like little porcelain statuettes, and they were totally intact."
Vessel can slice into fuselage
The ROV would be tethered to a larger naval ship via a fibre optic "umbilical cord" that also powers it, allowing the underwater vessel to explore the ocean depths for days at a time.
Once at the bottom, it would be able to remove, cut, slice and tear away fuselage from a wrecked plane in order to reach the pinger. The cylindrical pingers on black box recorders typically weigh seven to 10 kilograms. The vessels are able to lift items weighing more than 360 kilograms.
"It’s probably bolted down to something inside the aircraft, but these things can cut into something no problem," said Paul Tidwell, a deep-ocean salvage expert most famous for finding the sunken Second World War-era Japanese submarine I-52 in 1995.
Tidwell, who has participated in dozens of deep-water recovery explorations in the past 25 years and also advised director James Cameron on lighting techniques for 1997’sTitanic, said it could take three or four hours for the submersible to return to the surface with any objects from 4,500 metres deep.
He notes there is worry about the battery on the pinger dying.
"They do tend to overbuild these things, so hopefully it can last a little longer," he said.
