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Deep water search for jet could turn on robot subs

Two miles down or more and darker than night, the ocean becomes a particularly challenging place for human searchers.

If the wreckage of a missing Malaysian airliner rests somewhere in the Indian Ocean's depths, then investigators will likely need to entrust the hunt at least partly to robot submarines and the scientists who deploy them to scan remote swaths of the seafloor.

Such unmanned subs, called autonomous underwater vehicles or AUVs, played a critical role in locating the carcass of a lost Air France jet in 2011, two years after it crashed in the middle of the south Atlantic. The find allowed searchers to recover the black boxes that revealed the malfunctions behind the tragedy.

That search keyed off critical information: The search area for the Air France jet was much smaller than that for Malaysia Airlines Flight 370, and the first pieces of wreckage were recovered within days of the crash. Even then, it required two years and four deep water search missions before a team from the Woods Hole Oceanographic Institution, using an AUV equipped with side-scan sonar, located the jet about 12,800 feet (3,900 meters) underwater.

"Air France 447 is a bit different from Malaysian Air 370 in that we had a few more clues to work with," said Dave Gallo, who led the search team from Woods Hole, located on Massachusetts' Cape Cod. The independent research institution has offered its services to investigators but has not been asked to join the current search effort.

Before unmanned subs can be sent down to look for the Malaysian jet, the search zone must be narrowed considerably. The size of the search area changes daily because of factors such as currents; on Wednesday it was 221,000 square kilometers (85,000 square miles).

But if investigators can zero in on an approximate crash location, they will likely turn to AUVs to begin the methodical task of tracking back and forth across miles of ocean floor in search of anomalies that might be wreckage.

"I like to think of it as mowing the lawn. You want to cover every bit of it," Gallo said.

"You need a little bit of luck and a lot of prayer that the oceans are going to cooperate, and then off you go."

The unmanned subs used by the Woods Hole team were developed as tools to research and monitor relatively shallow coastal waters, measuring variables like salinity and temperature over wide areas for hours on end. But AUVs are increasingly harnessed to perform some of the most demanding underwater jobs.

The U.S. Navy uses them to search for underwater mines because they can stay below the surface of even very cold water much longer than any diver, without the worry of exposing a human to danger. Energy companies employ unmanned subs to survey the floor at underwater drill sites.

In 2009, California's Waitt Institute sent down a pair of AUVs that surveyed more than 2,000 square miles of South Pacific ocean bottom over 72 days in an unsuccessful search for Amelia Earhart's plane.

The area off western Australia where search planes and aircraft are looking for the Malaysian jet slopes from about 2,600 feet (800 meters) to about 9,800 feet (3,000 meters) deep. But part of the zone drops into the narrow Diamantina trench, about 19,000 feet (5,800 meters) down.

"Let's hope the wreck debris has not landed over this escarpment. It's a long way to the bottom," said Robin Beaman, a marine geologist at Australia's James Cook University.

The U.S. Navy last week sent a Bluefin-21 autonomous sub to Australia to prepare for an eventual deep water search. That sub can dive to about 14,800 feet (4,500 meters). The largest unmanned subs used by Woods Hole researchers are built to reach depths of about 19,700 feet (6,000 meters).

Searchers can also use tethered submersibles, towed by ships from cable that allows for real-time data transmission to the surface and a continuous supply of power to the vehicle. But it is a very slow process. AUVs can scan a larger area more quickly, without being affected by conditions on the surface. But they must be brought back to the surface to recharge, and for researchers to download and analyze their data.

Even so, they are much better suited to the job of deep water search than any manned sub, whose descents are limited by air, light and power, as well as safety concerns, said William Sager, a professor of marine geophysics at the University of Houston.

Sager recalled that in 2000, when he climbed aboard a sub and ventured 5,600 feet (1,700 meters) down to the bottom of the Gulf of Mexico, all those factors limited time on the sea floor to just four hours, moving at a crawl. A researcher looking out a porthole into even the clearest water with a very bright light can't see beyond 100 feet, he said.

Unmanned subs are far more flexible. When Woods Hole engineers built their first REMUS 6000 sub a little more than a decade ago, they tested it off the Bahamas by driving it down a trench the scale of the Grand Canyon, said Chris von Alt, who led the team that developed the craft and then co-founded Hydroid Inc., the Massachusetts manufacturer of the subs.

The REMUS sub - nearly 13 feet long, 1,900 pounds and mustard yellow - is equipped with sonar that can be programmed to capture images of vast stretches of seafloor and the objects resting there. Powered by a lithium battery, the unmanned subs stay below the surface for 20 to 24 hours. Scientists on the surface are now able to modify instructions to the sub via an acoustic link that allows them to look at bits of data gathered by the vehicle, von Alt said.

But they don't know what the sub has found until it surfaces and its data is fully downloaded to a computer.

The task requires patience and, for researchers whose livelihoods are focused on ocean life, a willingness to harness their expertise in a grim but necessary pursuit of answers.

"That's why you do it," von Alt said. "One of (the reasons) is, 'Why did it happen?' But the other is to get closure for the families who have suffered through the tragedy."

Join the discussion

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hway395 April 02 2014 at 10:38 AM

I haven't heard the costs going into the last 4 wks of searching but MAYBE this newest approach is the most expensive? Kinda like medical tests; Dr./clinics/hospitals begin with the least expensive exam & move up.

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b19821 April 02 2014 at 10:38 AM

What will they try next, DRAINING the Indian ocean?

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b19821 April 02 2014 at 10:32 AM

What a joke to use this when you are finding NO DEBRIS on the surface. Dog and pony show.

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yorkelectrical1 April 02 2014 at 10:57 AM

Can you believe that this double decker 777 flew under Singapores "modern" radar , undetected?

If th is plane can fly under that radar, don't tell me they couldn't have flown through India, Packystan, and any other muslim loving country.

That plane, dear people is safely in a hanger, somewhere , waiting to re emerge in her full glory as a United, Delta, British Airways........or any major Commercial Airline........loaded with the minimum of 16 hours fuel AND explosives.

It will make 9/11 look like a walk in the park.

Let's hope we find her before she finds us.

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valdemarjr April 02 2014 at 10:38 AM

The title of the story says "subs MAY be brought in" .... well ARE they or AREN'T they?
The story then includes statements such as:
"The independent research institution has offered its services to investigators but has not been asked to join the current search effort."
- AND-
"The U.S. Navy last week sent a Bluefin-21 autonomous sub to Australia to prepare for an eventual deep water search." EVENTUAL???!!!???

I don't think I'm the only person to believe that for some reason this ENTIRE "operation" seems FISHY, and the powers that 'be' have no intention on SERIOUSLY searching for this plane. The daily media circus with THIS detail and THAT detail and REVISED details.... is getting ridiculous. China should have taken over the entire search operation from DAY ONE.

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abudotcom April 02 2014 at 10:12 AM

a never ending story..... I feel terribly for the families of the 239 on board....

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quincy_maxwell April 02 2014 at 11:25 AM

Nothing like waiting too long to bring in the proper equipment.

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1 reply
sunbm quincy_maxwell April 02 2014 at 11:36 AM

Also, read the article above and maybe get together with johnmarlin.

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s4296ee April 02 2014 at 9:36 AM

There are stories that the plain is at a military base on Diego Garcia Island- a passanger sent a cell phone picture and text from there last week saying they were being held prisoner- why won't NBC CBS FOX,ABC cover this story???????? I personnaly have written them asking for them to try and clarify this- but no response-- just what the hell is going on here ?

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1 reply
Mark s4296ee April 02 2014 at 9:53 AM

Where did you hear that from and who received the text? That would be some story if it's true. At this point I wouldn't put anything past our government!

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1 reply
valdemarjr Mark April 02 2014 at 10:56 AM

YES - just google the words "passenger cell phone Diego Garcia" and all kinds of stories will pop up. ALSO, if you go on "Google Maps" and take a look at this island, on Satellite View - and you attempt to zoom in - certain portions of the island SUDDENLY become shrouded in 'cloud cover' .... which 'cloud cover' includes straight horizontal lines which tells you what? They're FAKE and there is a REASON for the 'cloud cover'.

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sachfoxo April 02 2014 at 9:10 AM

I am tiered hearing about them looking in the totally wrong spot. Either governments are hiding the fact that they know where the plane is and it certainly is not in the water. If the Chinese find out ( and they will) who was in on the conspiracy to take the plane , all heck is going to break out . The Chinese army is one of the largest in the world . I am backing the Chinese people on this one .... there will be no one left in that country along with any other country's who were involved. ACT of War !

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apollospeaks77 April 02 2014 at 9:41 AM



cause Flight 370 to disappear by moving the Bermuda Triangle to the Indian Ocean?
Of course not. But for an unusual look at this mystery googleb www.apollospeaks.com

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