MH370 Seabed Search Begins in Four-Mile Deep Indian Ocean Waters

Investigators hunting wreckage of Malaysia Airlines Flight 370 are set to scan the ocean floor in waters as much as four miles (6.4 kilometers) deep in the southern Indian Ocean today, amid a renewed hunt for the vanished plane.

The GO Phoenix search vessel is scheduled to arrive in its search zone today and start about 12 days of sonar surveys, according to a website statement last week by the Australian Transport Safety Bureau that’s coordinating the operation. Two more ships are preparing to start work in the region as part of a year-long search.

The survey of the ocean bottom remains the best hope to find the wreckage of the Boeing Co. 777-200, which may help answer how the plane disappeared en route to Beijing March 8 with 239 people on board. An earlier scan of 850 square kilometers (330 square miles) of seafloor in April and May, prompted by what were at first believed to be signals from the aircraft’s black box emergency beacon, found no debris in what is the world’s longest search for a missing plane in modern aviation history.

“The complexities surrounding the search cannot be understated,” the ATSB said on its website. “It involves vast areas of the Indian Ocean with only limited known data and aircraft flight information.”

Martin Dolan, chief commissioner of the Bureau, said in a Sept. 10 interview that he was “cautiously optimistic” the plane would be discovered, based on the amount of analysis performed on data indicating the path of the aircraft.

Final Resting Place

The only clues so far to the final resting place of the Malaysian Airline System Bhd. aircraft have been data exchanges with an Inmarsat Plc satellite, which suggested it ditched somewhere along an arc of ocean west of Perth, Australia.

Survey vessels using ship-based sonar have scanned about 110,000 square kilometers of ocean along this arc, producing maps to help guide the ocean-floor search beginning today.

The resolution of the maps was about 110 square meters per pixel, Daniel O’Malley, a spokesman for the ATSB, said by e-mail. That compares to the 64-meter length of an intact 777-200.

The GO Phoenix, owned by Perth-based oil and gas services company Go Marine Group Pty., has been hired by Malaysia’s government and its state oil company Petroliam Nasional Bhd. It will tow a side-scan sonar vehicle close to the sea floor to search for features of the ocean bottom. The vehicle can cover 194 square kilometers per day, according to its manufacturer.

Flight 447

Side-scan sonar sends out beams of soundwaves nearly parallel to the ocean floor, and use the reflected sound to detect the ‘shadows’ of objects sticking above the surface. The technology was used to detect the wreckage of Air France flight 447 in the Atlantic Ocean off the coast of Brazil, as well as the Tudor warship Mary Rose under the seabed near Portsmouth, England.

The sonar being used by Phoenix is capable of spotting features as small as 100 square centimeters as far as 1.2 kilometers away, according to the manufacturer’s website. That’s equivalent to someone at one of the piers of San Francisco’s Golden Gate bridge picking out a compact disc case on the opposite side.

Two more vessels contracted by the Australian government from Dutch engineering group Fugro NV will also take part in the search.

The Fugro Equator is currently in the search area carrying out further ship-based sonar surveys and will start deep-sea work around the end of this month, according to the ATSB.

The Fugro Discovery is due to arrive in Perth’s port of Fremantle today to pick up search equipment and a crew.