How Did the Reunion Flaperon Float?

inboard end
Inboard end of flaperon, top. Click to expand.

One of the many important details yet to emerge publicly about the Reunion flaperon is how it floated in the water. Presumably, French investigators have immersed it in saltwater to see how it settles. Since the results of that test haven’t been released, the only clue available to us is the the sea life visible in photographs. As I’ve written, the flaperon is liberally encrusted with goose barnacles. These animals are a type of crustacean that attaches while young to a floating object and spends its entire adult life affixed to the same spot. Since they obviously can only survive underwater, every part upon which they were growing must have been well submerged for a considerable period of time.

Above, the inboard end of the flaperon, as seen from the top looking down. This is where the ID plate should have been attached. Barnacles are growing all around the rim of this end, and to my eye extend beyond the plane of both the upper and the lower surface, so this entire end appears to have been submerged.

More pics after the jump.

The next picture shows the other end, the outboard end, again looking from the top down.

Outboard end
Outboard end, upper side. Click to expand.

Again, barnacle growth is profuse all the way around, especially on the upper surface, but it seems to extend beyond the plane of the lower surface as well, though this is harder to see. Here’s a close up:

Closeup of outboard leading edge. Click to enlarge

Next is a shot of the flaperon upper surface. Barnacles scattered liberally about, though they seem to be happiest on the jagged exposed honeycomb where the trailing edge appears to have been ripped off; it’s the topmost edge in this image:

Top of flaperon
Flaperon upper surface, trailing edge at top and inboard side to the right. Click to enlarge

A view of the trailing edge shows that barnacles have enthusiastically colonized both the upper and lower surfaces:

Flaperon trailing edge, piece carried upside-down with inboard edge to the right. Click to enlarge

Finally, here’s a shot of the underside of the flaperon:

MH370 search: Debris found on Reunion being sent to France
Bottom of flaperon, with outboard edge to the right and trailing edge up. Click to enlarge

This one really deserves to be seen at full resolution. This is clearly the least barnacle-covered side of the flaperon–the critters seem not particularly to favor undamaged, painted surfaces. But it seems to my eye that even here they have colonized all the way around the edge of this face, in greater or lesser densities.

In other words, it’s barnacles all the way around.

UPDATE 8/27/2015: One of the most frequent comments I’ve received is that for an object that’s spent nearly a year and a half in the ocean, it doesn’t have much growing on it. Reader @Matbythesea posted a link to a story containing this image:

Click to expand.


It shows a Japanese skiff that was carried out to sea by the 2011 tsunami and washed up in Washington State 15 months later, so was adrift for about the same amount of time that a piece of MH370 would be today. Like the flaperon, it is covered primarily in goose barnacles, though perhaps of a different species. As it happens, I was on the phone yesterday with famed ocean-drift expert Curtis Ebbesmeyer, professor emeritus of oceanography at the University of Washington, talking about the flaperon, and he specifically cautioned me that it is not possible to nail down the route and time afloat of drifting debris from the animal life growing on it, because things grow at different rates depending on, or instance, how nutrient-rich the water happens to be. Still, the difference in population density is striking. One other thing I’d note is that it appears that the skiff floated with its stern in the air with a foot or two of freeboard, with algae growing on the surface just below the water, and the goose barnacles growing a foot or so deeper. On the flaperon, in contrast, we do not see an intermediate zone of algae growth.


38 thoughts on “How Did the Reunion Flaperon Float?”

  1. Sorry for being so clueless, but what is the importance of how it floated?

    To me, the flaperon is important because it confirms that MH370 crashed into the Indian Ocean. It may be important if it sheds any light on how or why. Will knowing how it floated help with that?

    Or do we suspect that it sinks like a stone and therefore has appeared as part of the conspiracy?

  2. What I’m getting is it means the (1) object was submerged (2)most of the time that it was in the water and (3) the size of the barnacles determines how old they are and indicate the minimum amount of time it was submerged. If the oldest barnacles are older than the length of time since the plane’s disappearance, it isn’t MH370. Or something like that 🙂

  3. @jeffwise,

    In your last image, I see no barnacles on the underside, nor any on the edges extending past the underside (i.e into air in a upside down floating scenario).

    At the top along the clean linear break, there are some but extending towards the top of the flaperon (downwards into water, in the above scenario).

    Inside the hinge bracket slot, bottom right of image, there are several barnacles, but none extending past the underside.

    All this would seem to match Mike’s model #2, where the flaperon model floats flat and around 90% submerged.

    The slot would be awash allowing barnacles to grow there, the trailing edge would probably also have been – just – awash and allow barnacles to grow towards the flaperon’s upper side, i.e. downwards into water.



  4. Could a 777 fly and land without a flaperon? I guess it would cause a few problems (I’m in IT, not aviation!) but could it have come off another plane that lost this part mid-air?

    Are there any records of emergency landings (rather than actual crashes) of 777s in this area?

  5. I would say it floated flat horizontally, not flat vertically and definitely mostly submerged (sans that one side with minimal barnacles) to pick up all the shells and barnacles as Mike says and as the French basically describe with their “entre deux eaux.” I’d go with the 90% submerged.

  6. During its 17 months at sea, the flaperon probably was tossed about quite a bit by wind and waves. Also it may have been bi-stable, floating upside up at one time, and upside down at another. Even the buoyancy may not have been constant, as internal spaces may have filled and drained depending on its orientation to gravity.

  7. It seems to me it could be easy to make an experiment. Either of the two Australian ships making searches in the search area could do that. An object similar to flaperon in terms of the surface constituents, and covered with the same paint could be but underwater and tied to one of the ships or so. The purpose of the experiment could be sealife attached to the object, how it develops in terms of time. The object could be photographed daily and some measurements could be done daily. I do not think it would cost much.

  8. What are the possibilities this flaperon is a teaser, a plant, to throw off the investigators or further confuse the search?

  9. @Nina

    It is hard to imagine the search being more confused than it is.

    As Napoleon wisely advised – “Never interrupt your enemy when he is making a mistake.”

  10. @Bruce Lamon

    I share your opinion. The whole sidebar into the floating flaperon physics seems like something to do while we are waiting for something important to happen. The fact is it floated. Who cares if it was 90% submerged or 80% submerged or 87% submerged?

  11. @jeffwise

    Jeff, can you point out why the orientation of the flaperon drifting in the water is considered important? Is it to do with whether there is enough surface exposed on the flaperon for it to be carried by the winds, as well as the ocean currents? In the location of the current search area, the prevailing winds are a strong westerly. So if this is the case, and he flaperon was in the water like an iceberg floats on water, then wouldn’t the flaperon then have ended up in Western Australia rather than Reunion Island? And that’s IF it was in the SIO in the first place. Is this why the orientation of the flaperon in the water important?

  12. @Velocity, @DennisW, The issue is not how much was submerged, but how much projected above the surface. Based on my eyeballing of the debris, the answer appears to be “zero.” And this is problematic, because inanimate objects cannot float neutrally. This is an issue that was raised by an anonymous source in La Depeche article.

  13. I have to question the assumption that “they obviously can only survive underwater.” Perhaps these goose barnacles are of a variety that truly can’t survive without constant submersion, but generally, goose barnacles are commonly found in the intertidal zone, meaning that they spend hours every day outside the water during low tide. Given that the flaperon is relatively thin and certainly at least partially submerged, it’s easy to imagine that water frequently sloshed over the top. Therefore, barnacles could have lived on every surface, even if it was floating with the same side up the whole time.

  14. @Kimber, You are thinking of acorn barnicles, which evolved from goose barnacles by developing the ability to avoid dessication in the intertidal zone. Goose barnicles will die if exposed to the air. Also, bear in mind that floating objects do not experience periodic immersion due to the tides; whatever’s above the waterline is “high and dry.”
    In time, the growth of barnacles, algae, mussels etc will gradually add weight to the object and can eventually sink it, at which point it falls the bottom. There the accreted growth can die and drop off, and the object can resurface. So it is possible for an object to float mid-water column, but dynamically, not statically.

  15. Perhaps this comment on PPRuNe makes sense?

    “an object without any active buoyancy control will either float or sink. It will not remain suspended mid depth. In fact the feedback that does apply (compression) further promotes this behaviour. However ! a heavy object with only a fraction percent buoyancy . when subjected to heavy swell will spend most of its time completely submerged ! This because when submerged there is only a small force bringing it back to the surface, …”

  16. Could the flaperon have been partially attached to the wing, keeping it submerged until being dislodged or broken off from metal fatigue by means of current/tidal flow? If that was the case, would that suggest that the part was submerged somewhat shallow?

  17. I was interested how clean the flaperon and the fragment found at Vabbinfaru were so I had a look at the composition of aerospace paints. The paint that would have been used on a plane of mh370 vintage would have contained chromate. In a marine environment, this would have acted as a mild anti-foulant.

    Apparently, the gooseneck barnacle can survive in the intertidal zone so it really doesn’t need to be continuously submerged to survive.

  18. @Pat Janseen, We’ve discussed the intertidal zone issue and the consensus seems to be that Wikipedia is wrong on this point; goose barnacles do not live in the intertidal zone.

  19. I can’t speak for all species, but goose barnacles certainly can survive out of water. Here in Spain, Pollicipes pollicipes (percebes) are a delicacy and you see them all over the rocks on the northern coast and estuaries (Galicia and Asturias). As the tides recede, they are exposed on the rocks for many hours. People scale down the cliffs and climb exposed rocks to harvest them. It’s one of the most dangerous jobs in the world.–644×362.jpg

    You can see them alive and kicking out of the water on any beach or rocky cove in that part of Spain.

  20. If all the 777’s are accounted for, are there sources of flaperons available to an individual or a group that may wish to fake evidence to mislead? Who would gain from such an act other than to put an end to the mystery or a hoax for fame to show it can be done? I would guess there isn’t a great number of stockpiles of this item that inventory can’t be verified for a missing item. Very convenient that an ID tag just goes missing.


  22. @Mariposita, Floating debris is not like a rock in a tidal zone; it is not periodically immersed. Whatever’s above the water line stays above the water line.

  23. Kimber hit the nail on the head. I was an underwater hull cleaner for 12 years. I know more about the nature of marine growth than anyone should ever know. In short, lots of goose barnacles (and other types of barnacles) thrive in the tidal zone, where they go through alternating periods of wet and dry…for many hours at at a time. An object bobbing in the water, near or on the surface, only needs to be at least partially wet some of the time for barnacle larvae to find a purchase. It doesn’t take much time or a lot of water. And the growth rate varies considerably, depending on species, water temperature, and nutrient levels. The same species will grow at different rates throughout the season depending largely on temperature changes. Cold water slows things down. As someone who spent way too many years watching barnacles and mussels grow on things, I’d say that the amount of growth on the flaperon appears highly plausible. Were it to have floated through the North Atlantic, or the Central Pacific, or some other region, the growth types and quantity might be different. But it’s not surprising that the flaperon is covered with goose barnacles, or any other barnacle for that matter. It’s not a mystery, it was simply inevitable.

  24. Jeff:

    Very interesting. Finding one piece only is more suspicious than finding none at all.

    Also, can you explain why the GeoResonance Bay of Bengal claim has never been investigated?

  25. I hope that you’re being facetious, but just in case you’re serious…Why would you assume that the falperon spent all of its time in the open air? Did you witness its attitude in the water prior to its arrival on the beach? So, none of its surface was ever covered with water at any one time? One portion of it always remained high and dry? Having spent over a year in the ocean, experience who knows how many storms and rough seas, that seems highly improbable.

    Besides, much of the debris that is drifting around out there spends a lot of time largely submerged. It’s just buoyant enough to remain in the upper tier of the water column as the currents push it around. Only the most buoyant materials remain largely exposed: things like plastics, wood, Styrofoam, etc. I worked underwater for 12 years in some of the most garbage-infested waters imaginable. I’ve seen how debris moves through the water first hand, so I’m not going to argue with you about it.

  26. @JeffWise
    I agree with you 100%. It seems suspicious to me that the smallest section of the plane is the one found. Is it possible that having landed on the ground by terrorists, the flapperon was mechanically ripped from the plane, and submerged in a body of ocean water to collect barnacle development. The motive for such action, as long as the mystery on unsolved, people will be fearful. Isn’t that the definition of terrorism

  27. Sorry, Mr Wise — you lost all credibility when you insisted that barnacles can’t grow and live on a surface that isn’t submerged 100% of the time.
    Anyone who has ever seen any kind of flotsam or marine litter is aware of this!
    Your “high and dry” scenario would only be possible in a completely and perpetually glass-calm sea — ie, impossible!

  28. What bothers me, is that goose neck barnacles are not generally found in the Indian Ocean, so did these barnacles attach themselves to the flaperon before it found itself in the Indian Ocean? Ie. Did they perhaps attach themselves off California, where they are found in abundance, and the flaperon was then placed in the Indian ocean, or on Reunion more recently than the plane crash?

  29. Jane, I spent a fair bit of time researching Lepas biology back then and as I recall the species found on the flaperon were endemic to the area.

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