Flight 370 effort could soon shift from search to recovery

The Bluefin 21, the Artemis autonomous underwater vehicle (AUV), is hoisted back on board the Australian navy's Ocean Shield in the southern Indian Ocean. (U.S. Navy)

The team of international investigators hunting for Malaysian Airlines Flight 370 has "unquestionably" located the missing jetliner and could soon have high resolution images of the wreck site, an expert in deep sea recoveries of ships and planes told FoxNews.com.

There is virtually no chance that the pings picked up by ships towing sophisticated listening devices could be anything other than signals emitted by the plane's flight data recorder, or "black box," David Mearns, of Blue Water Recoveries, a United Kingdom-based company that holds the Guinness World Record for the deepest ocean recovery and has assisted searches for sunken planes.

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"This cannot be coming from anything else," Mearns said. "This is the best equipment there is, and the signal is unmistakable.”

If Mearns is correct, what remains is to pinpoint the precise location, map the debris field on the seabed and begin recovering parts of the plane and, possibly, the bodies of victims. The site is some 15,000 feet, or 2.8 miles deep, Mearns said, and in a remote part of the Indian Ocean that is deeper than the Titanic's final resting site and too deep for humans to dive.

Mearns, who is not involved in the effort but knows people who are and has been through the process himself, said he believes Angus Houston, the retired Australian air chief marshal heading the Joint Agency Coordination Center, is deliberately awaiting incontrovertible visual evidence out of respect for the passengers' families. The search for the Boeing 777, which disappeared March 8 with 239 passengers and crew, has been flawed from the beginning. So far, an estimated $50 million has been spent on the effort, which involves teams from the U.S., Australia, Great Britain, China and Malaysia.

"The reason they haven’t announced it is what the families have gone through in terms of all the false leads, and they are demanding that they see pieces of wreckage," Mearns said.

Houston himself on Tuesday gave his strongest indication yet that he believes the pings mean the searchers are above the wreck site.

"(The analysts) therefore assess that the transmission was not of natural origin and was likely sourced from specific electronic equipment," Houston said. "They believe the signals to be consistent with the specification and description of a flight data recorder.

“I believe we’re searching in the right area,” he added, “but we need to visually identify aircraft wreckage before we confirm with certainty that this is the final resting place.”

If the pings are indeed from the black box, the searchers may have won a race against time. The batteries that power the recorders are only built to last about a month, and that's how much time has elapsed since the plane disappeared. Once the battery dies, finding the plane could become nearly impossible, according to experts.

Mearns laid out the search process in phases, with Phase I, a search for a floating debris field, having failed. Because investigators spent weeks looking in the wrong places, tell-tale pieces of the plane have long since dispersed or sunk, he said. The next step was to hunt for the plane by listening underwater for signals transmitted from the black box, an effort that even Mearns saw as nearly hopeless until ships with sophisticated listening equipment began picking up signals in recent days.

Mearns' company set a record in 1996 by probing the wreck of the World War II German blockade runner the "MV Rio Grande," at a depth of 20,000 feet in the South Atlantic. It also took part in the recovery of the cockpit voice recorder from South African Airways Flight 295, which went down in the Indian Ocean in 1987, killing all 159 aboard.

Now, investigators are working to "box in" the source of the ping first picked up by a Chinese ship, then heard again on Sunday by crew aboard Australian naval ship Ocean Shield, which has a sophisticated pinger locator on loan from the U.S. Navy. They have to hope the battery holds out long enough to help them triangulate the box's location.

By crisscrossing over the area where the pings were detected, searchers can narrow the search field from 300 square nautical miles or so to 50 or less, Mearns said. Once that is done, the next phase -- a side-scan sonar search of the seabed using the Bluefin 21, a submersible vehicle that can drop down 2.5 miles to map the seabed. That tool, 21 inches in diameter and shaped like a torpedo, owned by U.S. Navy contractor Phoenix International and now aboard the Ocean Shield, will help craft a route and plan for the next phase, carried out by an unmanned ROV, or remotely-operated vehicle. "The Bluefin has a camera that can get an entire map of the debris field, with high-resolution images," Mearns said.

Once investigators on the surface have the wreckage mapped, the ROV will be sent down to recover the black box. Information gleaned from that will tell them what else they need to recover. In the case of TWA Flight 800, which went down off the shore of New York's Long Island in 1996, investigators recovered nearly all of the plane, reconstructing it in a hangar in an effort to determine what caused the crash. In other cases of plane crashes over the ocean, only the black box was recovered, because information contained in it answered the key questions.

"Investigators will recover whatever they feel is necessary, depending on what information they get from the black box," Mearns said. "That information may direct them to pick up a larger or smaller amount of wreckage.”

The ROV could also be used to recover bodies, he said. In the case of Air France Flight 447, which went down in the Atlantic in 2009 after departing from Brazil for Paris, 154 bodies were recovered during a process that involved robotic submarines and spanned two years. Some 74 bodies were never found.

While most of the work in recovering Flight 370 will be done aboard the Ocean Shield, the land-based component of the investigation will take place at the nearest sufficient port, in Perth, Australia, Mearns said.