Search for MH370 reveals secrets of ocean depths – Part 1

By on 23 August, 2016
mh370-malaysian-airlines

Source: Flickr user Byeangel CC BY-SA 2.0

 

This two part article was written by Position founding editor Jon Fairall and was first published in the June/July 2016 issue of Position magazine.

On 8 March 2014, a Boeing 777 registered 9M-MRO operated Malaysia Airlines Flight 370, a scheduled service between Kuala Lumpur and Beijing. It took off half an hour after midnight and at 1:19 in the morning the captain of the aircraft, 53-year-old Zaharie Ahmad Shah from Penang, made a routine call to Air Traffic Control. Neither he, his aircraft, or the 238 other people on board, were ever heard from again.

In the two years since, the overwhelming response to the incident, from both flying veterans and the interested public, has been incredulity. How is it possible that a big jet aircraft can simply disappear in a world where accurate satellite positioning and global communications networks are routine?

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There are a hundred theories, each more unlikely than the last, as to what happened on the aircraft. There is little evidence with which to differentiate between them. In modern mythology, MH370 has come to occupy the same place as the Mary Celeste did in the world of sail. In 1872, she was found off the Azores, perfectly seaworthy, but absent her crew. Like the souls of MH370, they had simply vanished. Like MH370, their fate obsessed a generation.

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The search area along the 7th Arc, derived from Inmarsat data. The most dominant feature of the seafloor is a fossilised plate boundary called Broken Ridge that stretches from south of Perth, into the southern Indian Ocean where it meets the southern edge of the Ninety East Ridge. Source: Geoscience Australia

 

Entering uncharted territory

There is one group of people who will reap some reward from the disaster however. For oceanographers, geologists and geomorphologists, the deep sea search for MH370 has given them their best view yet of the deep ocean floor south and west of Australia.

They have received this glimpse of the remote sea floor because, to be accurate, MH370 didn’t just vanish with that last call from the aircraft. The aircraft’s flight path has been reconstructed for six hours after 1:19. Four days after the incident, the chief of the Royal Malaysian Air Force, Data Sri Haji Rosian Bin Saad, announced that an unidentified aircraft had travelled across the Malay Peninsula in the early hours of 8 March. He said it was last sighted 370 km north west of Penang.

Even more of the flight path was reconstructed by investigators at Inmarsat. They demonstrated that the aircraft turned left after that last radar sighting, heading deep into the southern Indian Ocean.

London-based Inmarsat owns communications packages on planes which, in the case of MRO, was used to send messages between the two Rolls Royce Trent turbines and engineers at Rolls-Royce. Although this messaging system had been turned off, things were arranged so that every hour the system generated a short message, or ping, to test the data path. Six valid pings were received from the aircraft, the last at 08:11.

Then at 08:19 there was an unscheduled ping, as if the device had turned off and then rebooted. Authorities suspect one of the engines ran out of fuel at that point, interrupting the electrical supply. That was the final message from the aircraft.

Although the system did not generate a position fix, by some adroit re-engineering of the signal, it was possible to calculate the position of the device at each ping, somewhere along an arc on the Earth’s surface. Inmarsat first pin-pointed the position of the last ping at a point about 1,000 km west of Exmouth. By the time they had refined their techniques however, the search area had moved about 1,500 km south and west, along the so called `7th arc’, to give a search area stretching more than 2,000 km, 90 km wide, from latitude 20 S to 39 S.

Piecing together the clues

The plane left other clues. Bits and pieces have washed up half a world away, on the coast of Africa. On 29 July 2015, debris was found in the sand on Saint-Andrea beach on the French island of Reunion, about 4,000 km west of the most likely impact site. Later analysis by the Bureau d’Enquetes et d’Analyses in Toulouse concluded the debris was part of the control surface of the starboard wing.

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Multi-beam sonar reveals the bottom in unprecedented detail. Source: Jon Fairall.

Then, in February 2016, a US holiday maker in Mozambique, Blaine Gibson, was walking on a sandbank in the Mozambique Channel when he found a suspicious fragment. The news interested a South African teenager, Liam Lotter, who had been 300 km further south, in southern Mozambique, the previous December. He had also found a fragment on the beach that he had kept. Both pieces were flown to Australia for analysis.

On 19 April 2016, the Australian Transport Safety Bureau released a report on the two pieces of debris. One piece was identified as part of the flap track fairing. (Three of them protrude from the trailing edge of the wings on a 777.) The other piece was a panel from the tail wing. In both cases, the ATSB confirmed the pieces were “almost certainly” from 9M-MRO.

More recently, some other items have come to light. A damaged suitcase and other flotsam was found in the Mozambique Channel. More debris was found on the island of Reunion. A piece of the engine cowling turned up in Mossel Bay in South Africa. An additional piece of debris, possibly from the interior of the aircraft, was found on Rodrigues Island, 600 km west of Mauritius.

Although more than 4,000 km separates the most easterly and westerly of these pieces, models of ocean currents used by CSIRO suggest the locations of these items are consistent with the Inmarsat-derived crash location. David Griffin, a physical oceanographer at CSIRO, has been working with data on ocean currents gathered by the US National Oceanic and Atmospheric Administration between 1990 and 1997.

The data, he says, is “consistent with MH370 having crashed near the 39°S-32°S segment of the 7th arc on 8 March 2014. The computer modelling cannot refine the ATSB’s sea-floor search area – it just increases our confidence that the flight path analysis underpinning the choice of sea-floor search area is not wrong.”

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3D modelling from the MH370 search area encompassing the seabed on and around Broken Ridge. Source: Geoscience Australia

 

None of this goes to answering the big question about why the incident happened. For that, investigators would need access to the aircraft itself and any clues remaining locked up in the flight data recorders.

Finding the wreck is the Holy Grail of the search effort. At this writing, two year’s work by a fleet of survey ships and the expenditure of over $100 million has been fruitless. At least, it has been fruitless for the families of those whose loved ones perished, for the aircraft engineers who would like to know how to stop this happening again, and for Malaysian Airlines, who would like to assure its passengers that it is not cursed by some almighty power.

 

This article is the first in a 2-part exclusive feature article. Part-2 will delve into the technologies being used in the search for MH370 and the findings so far.

To read Part-2, sign up to the spatial newsletter to ensure you catch it when it is published next week. Otherwise please subscribe to Position magazine to continue reading it in full.

Jon Fairall is the founding editor of Position magazine. He now operates as a freelance journalist and author.

 

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