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The difficulty of searching for MH370 in a giant rubbish patch

Frustratingly, the search for missing Malaysia Airlines flight MH370 has turned up many floating objects, but none of them are from the plane. That’s largely because the latest search area is likely to…

Debris or not debris? Floating rubbish could hamper the search for MH370. AAP Image/AP Pool, Kim Christian

Frustratingly, the search for missing Malaysia Airlines flight MH370 has turned up many floating objects, but none of them are from the plane.

That’s largely because the latest search area is likely to be in one of the world’s hotspots for accumulated debris – an area nicknamed the Indian Ocean garbage patch.

Previous and current search areas for missing airplane MH370, as well as predicted regions of marine debris accumulation in the Indian Ocean

Location unknown

Based on satellite tracking and fuel consumption of the MH370 aircraft, it has been proposed that the plane probably crashed somewhere in the southeast Indian Ocean.

As the exact location is unknown, the current priority is to locate floating debris from the aircraft, so that oceanographic models can be used to narrow the search area.

The sizes and types of floating debris resulting from an aircraft crash depend on how it hit the water. With previous plane crashes in the ocean, the floating debris included pieces of the aircraft’s structure (such as wings and fuselage), cabin equipment including seat cushions and life vests, personal items like water bottles, and victims' bodies.

While some pieces of debris sink over time, others will stay floating on the surface – the only clues to the location of the rest of the wreck.

Vast debris fields

The problem is that there are already vast amounts of debris floating in the world’s oceans. The presence of this debris in the search region means that crews are wasting resources and time trying to identify floating objects unrelated to MH370.

The most abundant type of marine debris is tiny plastic fragments less than 5 mm in length. However, these do not hamper sea search operations, as they are invisible to observers aboard ships and airplanes.

Ocean debris large enough to be spotted from aboard ships are mostly chunks of plastic left over from the disintegration of larger objects. Plastic bottles, bags, buoys, rope, expanded polystyrene items, and fishing nets are also very common. Nets are often big enough to be seen by airborne searchers.

Fishing gear spotted by an observer aboard the airplane Royal New Zealand P3 Orion during the search for the missing airplane MH370. Source: AFP

Swirling currents collect rubbish

Although rubbish is found throughout the oceans, some places are more litter-strewn than others. Unfortunately for those looking for MH370, their search area is probably right in the middle of one such garbage patch.

Each of the world’s five major ocean basins feature large, loop-shaped surface currents called gyres. Driven by wind patterns in the subtropics, the gyres in the Northern Hemisphere (the North Pacific and North Atlantic gyres) rotate clockwise, whereas those in the Southern Hemisphere (the South Pacific, South Atlantic and Indian Ocean gyres) spin anti-clockwise.

All of these gyres funnel debris into “convergence zones” where floating rubbish accumulates – hence the nickname “ocean garbage patches”.

Mean plastic concentrations (pieces per km2) at different parts of the world’s ocean. The currents that form the subtropical gyres are displayed as black arrows in the top map, together with mean concentrations of floating debris, as measured by searches from vessels. The bottom map shows mean concentrations of microplastics, as measured by sampling. Note that they are far much more abundant than large marine debris. Adapted from Boyan et al., www.theoceancleanup.com

Surveys of ocean debris have confirmed the locations of some of these plastic pollution hotspots, although the existence of others is largely surmised using computer models.

We know that large plastic items, of the kind that could frustrate the search for MH370, are found at high densities in some well-studied areas. More than 10 pieces per square kilometre have been found in waters near populated coastal areas, in the Mediterranean Sea, and in the subtropical North Pacific (the infamous North Pacific garbage patch).

But the garbage patch in the southern Indian Ocean is still poorly mapped, and model predictions of its whereabouts differ considerably between studies. At least one analysis puts the current MH370 search area right in the middle of the Indian Ocean garbage patch (although other research says otherwise), meaning the chances of encountering unrelated debris may now be higher than in previous search regions.

Describing the difficulty of the search, Australian Defence Force vice-chief Mark Binskin said: “We’re not searching for a needle in a haystack, we’re still trying to define where the haystack is”.

Add ocean debris into the mix, and we may very well find that when we finally track down the haystack, it’s full of things that look like needles.

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22 Comments sorted by

    1. Peter Davies

      Bio-refinery technology developer

      In reply to Alice Kelly

      By all accounts it appears whoever had control of the plane took a series of deliberate and pre-planned manoeuvrings and flight paths to avoid detection. The suggestion then that they then flew on till they ran out of fuel seems to me implausible since with this level of planning why leave the final destination to fate?

      I would expect they knew about the garbage patch, I also suspect what Alice suggests that they put the plane down under controlled crash to minimize debris. They clearly did not want to be found.

      Why???

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    2. Peter Davies

      Bio-refinery technology developer

      In reply to Peter Davies

      I am going to add one more flight of fancy to the haystack problem, if the intent is not be found, and you know your aircraft emits a satellite ping every hour, and you know precisely when this occurs, then flying in a straight direction on seemingly your final leg for a few hours, but then changing course abruptly after your last "Ping" and flying on at full power for 50 minutes extends the search area by hundreds of kms in every direction, including back the way you came... I am sure the search authorities have considered this, but it is a big ocean. My thoughts and heart goes out to the families left behind.

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    3. Ted O'Brien.

      Farmer.

      In reply to Peter Davies

      No fuel means minimal oil slick, though wings might float for a while.

      If the plane was intact and nose dived into the water, how deep would it penetrate. Every 10 metres of depth would increase the water pressure by an atmosphere, compressing the gas in foam components.

      If it penetrated 50 metres or more under the surface, a lot of stuff that might have floated if on the surface would instead sink.

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    4. JB Rawson

      Writer

      In reply to Alice Kelly

      Alice, the photo in that link is disgusting. I've edited a lot of stories about ocean garbage, but never seen a pic like that before. Thanks (kind of)!

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    5. Bruce Tabor

      blogger

      In reply to Alice Kelly

      Alice, I agree. I suspect for whatever reason, this was a sophisticated murder-suicide, with the pilot not wanting to leave evidence of agency, for reasons of honour, life insurance or whatever.

      My guess: the pilot disabled all tracking he was aware of/able to disable then diverted the flight. The aircraft was flown to 45,000 feet soon after diversion and probably depressurised to kill the passengers and other crew. The pilot then flew to one of the world's most inaccessible regions, exhausting the fuel so as not to leave an oil slick and then put the plane down as gently as possible over the Diamantina Deep - at over 7km deep it is possible the deepest area of the Indian Ocean.
      http://en.wikipedia.org/wiki/Diamantina_Deep
      In any case the evidence would suggest that whoever did this simply did not want the aircraft and the cause of it disappearance to be found.

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    6. Alice Kelly
      Alice Kelly is a Friend of The Conversation.

      sole parent

      In reply to JB Rawson

      JB, if you go to the beach, lie in the sand next to a pile of fine shells, and then look at the coarser sand next to the shells and other bits.... much of the coarse sand is not sand but granulated plastic.
      I wonder if there's such a thing a a clean beach.

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    7. Allan Gardiner

      Dr

      In reply to Peter Davies

      It's quite possible that some of the flight crew and perhaps some other persons aboard flight MH370 parachuted to safety somewhere soon after its having been lost from radar, and either told some of the passengers which heading to take if they wished to take control of the aircraft, if they of course had access to the flight deck, or the pilots just engaged the autopilot before baling out so that the aircraft would head for a remote area like that of the Indian Ocean.

      Don't be surprised if some of those persons who were known to be aboard MH370 surface sometime down the track and are ready to spin a good yarn about how they miraculously survived, and would have of course identified themselves earlier, but amnesia or something else, like being held captive on foreign soil for several months/years made this quite impossible for them.

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    8. Greg North

      Retired Engineer

      In reply to Peter Davies

      Peter, they have had fires on planes that have had toxic fumes overcoming passengers and crew.
      If there had been an electrical fault that cut out communications and even navigation equipment, that would have been reason enough for the pilots to head off course towards where they thought nearest suitable emergency landing could be, hence the track west initially and then they may have thought about heading back south to KL and through a combination of navigational limitations and gradually becoming…

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    9. Greg North

      Retired Engineer

      In reply to Alice Kelly

      So the case has been heard and the jury has come in with Judge Alice doing a summary I see.

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    10. Greg North

      Retired Engineer

      In reply to Allan Gardiner

      You see lots of good yarns spun Allan, even without using parachutes and having amnesia, maybe something else though from a bottle.
      There's sure to be a plethora of novels, even another Lost and a few films come out in years to come.

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    11. Peter Davies

      Bio-refinery technology developer

      In reply to Greg North

      Greg, at the moment all we have is scenarios from limited official information, but from what has been released the plane not only changed direction but flew a via navigation way points also changing height where needed to (apparently) avoid radar.

      In terms of terrorists I am surprised no one has claimed responsibility already even if they had no involvement, but if some group actually did then I cannot see their silence as achieving anything except in a very narrow scenario which I won't put in writing on a public forum. There are limits to speculation.

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    12. John Doyle

      architect

      In reply to Alice Kelly

      It also means all seafood is contaminated. From plamkton to whales, no exceptions.

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  1. Kenneth Mazzarol
    Kenneth Mazzarol is a Friend of The Conversation.

    Retired Auto Engineer and teacher

    There is something fishy going on here. A powerful influence, is using the plane 'disaster' as a diversion from something else. Orchestrating another twin tower catastrophe somewhere perhaps in retaliation for Osama Bin.....what's his name????

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    1. Greg North

      Retired Engineer

      In reply to Kenneth Mazzarol

      " There is something fishy going on here. "
      It's a whale of a story you reckon do you Kenneth?

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  2. MItchell Lennard

    Researcher - Distributed Energy Systems

    Thanks for the interesting article

    While not wishing to add to all of the speculative nonsense , just to answer Alice's question as factually as possible.

    Without any pilot input at all the aircraft would land quite gently. The 777 Flight Control System (FCS) pitch channel has two envelope protection limits, one for overspeed and one for slow speed ( stall). Depending on the last Autopilot VNAV outer loop setting as the engines failed ( as fuel exhausted) the autopilot would either try and…

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  3. John Kelmar

    Small Business Consultant

    I cannot believe that dozens of satellites would have tracked this plane throughout its journey, as it is possible to identify a the face of a person in a crowded street in any city of the world.

    Unfortunately Australia and Malaysia do not own these satellites, and those that do are denying their existence.

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    1. Greg North

      Retired Engineer

      In reply to John Kelmar

      I think you may find John that many more satellites are tasked over land areas rather than oceans just in case you left the nit out of your double negative.
      As it is, there would then need to be satellites covering the Indian Ocean or other areas at the time of the planes suspected flight in a particular area and then all the footage from a few satellite transmissions would need to be examined, that having been done for some reports of debris that many days later would need to be found for examination as is occurring with planes and ships even if it all to date is just see flotsam.

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  4. Gary Meyers

    Honorary Fellow Marine Research at CSIRO

    Thanks for the article Chari and Julia. It's a nice bit of oceanography. Helpful I think.

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  5. Jack Humphrey Joseph West

    logged in via Facebook

    After the cargo has been reclaimed, the plane (and passengers(?)) was flown into the Indian Ocean with the surgical precision for NOT leaving any sign, parts, luggage, debris and or black-box! Let alone location!
    Alice K is rather spot on with her theory quote: "If the pilot did try to avoid detection, he probably tried to enter the ocean with minimum impact, if this is possible."

    Anything is possible: even remote controlled flying of the plane. Tony Abbott et al. has to simply ask the commander at Diego Garcia, or indeed the Commander in Chief, where is Peter Wood and the other passengers ... now? MH 370, "the plane may never be found" (Abbott) .......

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