How the MH370 Flaperon Floated — UPDATED

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Fig. 1: A population of Lepas goose barnacles growing on a skiff carried out to sea by the 2011 Tohoku tsunami.

Goose barnacles of the genus Lepas live exclusively on debris floating in the open ocean. Like other barnacles, their larvae spend the early part of their life swimming freely and then, in a final larval phase called the cyprid stage, search out a floating object on which to settle. Once they find a suitable object, says marine biologist Hank Carson, “cyprids in general do do a fair bit of exploration for that cementation spot” upon it, and with good reason: they’ll spend the rest of their life there. Among the criteria they assess is how crowded a spot is, what the underlying substrate consists of, and how deep it is. Once satisfied, they glue their heads in place.

In general Lepas barnacles like to spread out, and prefer a spot in the shade; they grow best away from the top of the water column. The reason is that close to the waterline, the rising and falling of waves periodically exposes the animals to the air, which interferes with their feeding. It’s unhealthy for them in other ways, too. “The uppermost centimeters of water are normally a quite harsh environment with strongly changing ecological parameters, like water temperature, salinity (heavy rains or intense evaporation in tropical areas). Moreover they are subjected to intensive UV radiation,” says Hans-Georg Herbig of the Institut für Geologie und Mineralogie in Cologne, Germany. “From several organism groups it is known that they avoid the uppermost centimeters of the water column.”

Given a healthful environment, Lepas barnacles are notoriously fast-growing. The animals evolved to live on floating organic debris which after a time will break apart and sink, so time is of the essence. Whereas a species of goose barnacle that lives attached to a rock might take five years to reach sexual maturity,1 Lepas can do it in mere weeks. Japanese researcher Yoichi Yusa and his colleagues raised L. anserifera barnacles on tethered debris in a bay in Japan and found that “individuals on the average grew from 3 mm to more than 12 mm in capitulum length within 15 days and some were brooding.” Thus, in less than a month after settling onto a piece of debris, Lepas can begin producing new generations to further their colonization.2

As a result Lepas-settled flotsam can become extremely crowded in short order, with individuals crammed onto every available surface right up to the uppermost limit of what they can survive. Pictured above in Figure 1 is a Japanese skiff that was swept to sea after the Tohoku tsunami in March, 2011, and made landfall on a beach in Washington state in June of the following year, meaning that it floated capsized for about 15 months. If you think it’s remarkable that the barnacles could have grown so huge in so little time, think again. “They grow really fast,” says Cynthia Venn, a professor of oceanography and geology at Bloomsburg University in Pennsylvania. “That boat could get covered like that in six months, even.”

Venn has studied the genus Lepas intensively for more than twenty years. For ten of them, she collected specimens from NOAA’s Tropical Ocean and Atmosphere array of research buoys dotted across the central Pacific Ocean, carefully preserving material that the maintenance crews considered pesky marine fouling. “It was basically a 3-D time series of barnacle settlement,” she says. “I couldn’t find anyone to take the project so I just did it myself. I was able to go two cruises, for the rest I sent my studentsand they then shipped the barnacles back to me so I could work on them. I’ve got hundreds of thousands of barnacles in my garage.”

Looking at the skiff more closely, we see that the upper part of the hull is ringed with a very well-defined boundary below which the Lepas are cheek-by-jowl (orange line in Fig. 2, below). Above that lies an intermediary zone, extending to the waterline (green line), where algae predominate. While some barnacles are visible, they are small and few in number. “They get a better shot at what they’re going to eat if they’re a little bit below that,” says Venn. “I don’t know if it’s too much UV or just they don’t like the temperature changes, or what.”

waterline and Lepas line
Fig. 2: A close-up view of the skiff in Figure 1, showing the waterline (green) and “Lepas line” (orange)


A Lepas line is also easily seen in the picture below (Figure 3), which shows meteorological research buoys before (“a”) and after (“b”) a 26-month deployment in the North Pacific. “The waterline is at the center (max diameter) of the buoy, where there is a seam in the hull,” says Jim Thomson, a scientist at the Scripps Institution of Oceanography who studies the buoys.3 “The barnacles appear to start about 10 cm below that line.”

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Figure 3: A deep-ocean buoy before and after 26 months in the North Pacific.


Here’s another piece of tsunami debris, this one a refrigerator that made landfall in Hawaii in October, 2012, meaning that it was in the water for just over a year and a half. Both the Lepas line and the algae zone are clearly visible. The waterline, Venn says, would lie about where the green algae shades into black:

Fig. 4: A Japanese refrigerator that washed up in Hawaii after the tsunami.


You may have noticed that while the hard part, called the capitulum, is of similar sizes in all these pictures, the fleshy, goose-neck part (called the peduncle) is dramatically smaller on the Hawaii debris. Like other fleshy appendages, peduncles can change in size fairly dramatically, especially when they’ve been pulled from the sea. “How long they are kind of depends on how long they’ve had to dry out,” says Venn. So when scientists talk about the growth rate of barnacles, they usually talk about the length of the capitulum.

How Composite Objects Float

According to reader Gavin Grimmer, The upper and lower surfaces of 777 flaperon are “made of  honeycombed composite – presumably carbon fiber” while “the leading edge is mainly made from high tensile aluminum (2024-T3) apart from the fibreglass doubler.”4 As a general rule, things made of composite material exhibit excellent buoyancy. The honeycomb materials which makes up most of the volume of the composite skin weighs only about 5 percent as much as water.5 Composite aircraft parts, therefore, tend to float fairly high in the water, like this:

Fig. 5: The vertical stabilizer of Air France 447.


Mike Exner, one of the leading members of the Independent Group, conducted his own study of how the flaperon must have floated, building a model out of plastic poster board. After the interior compartment was flooded it settled into the water like this:

Mike Exner flotation test
Fig. 6: Mike Exner’s model of the Reunion flaperon.


Another example of a composite floating object is this motor boat, which  capsized in a storm off the northwestern coast of Australia and then was carried for eight months by waves and currents across the Indian Ocean to the island of Mayotte, near Madagascar — a very similar route that the MH370 presumably took on its journey from the 7th arc. Though the resolution is too low to discern the Lepas line from the algae zone, you can clearly see which part was above the water and which part was below:

Fig. 7: An Australian motorboat that journeyed upside-down across the Indian Ocean.


Now let’s turn our attention to the 777 flaperon that washed up on a rocky beach on Reunion Island. More than two months later, the French authorities still haven’t released a report detailing what they’ve learned about the piece, which now resides at a facility near Toulouse. Fortunately journalists took photographs of the flaperon from every angle shortly after it was discovered so that just by gathering publicly available images from the web we can assess the whole surface.

As a general observation, we should note that the general shape of the flaperon is plank-like: rectangular when seen from above, with an airfoil cross section. In referring to the part, I will use the nomenclature shown in Fig. 8, below.

Figure 8. The parts of the flaperon.

Note that the geometry of the piece is essentially planar, by which I mean that the faces do not bulge outwards. As a result, if one point on the edge of an end-cap is underwater, and the corresponding point on the edge of the far end-cap is under water, then the surface between them will be immersed, too. (You can get a sense of this “flatness” in Figures 10 and 14, below.)

To begin with, let’s look at the outboard end cap. Barnacles, either individual or in clumps, are circled in green. I have not necessarily circled all of them, but at least those necessary to show the range of distribution. (To see the full-resolution version of this and all subsequent images, click on the link in the caption.)

Outboard end cap
Fig. 9. The outboard end cap. For full resolution image, click here.


Given that the end-cap is rimmed in barnacles, it must have all floated below the waterline. One could argue that a small portion of the strip marked with the red line could emerge from the water, but to my eye it lies between the outer edges of the barnacle clusters marked “A” and “B,” which would not grow up out of the water.

Moving on to the leading edge, we see in Figure 10 (below) that there is a substantial accumulation of barnacles on the outboard end of it, as well as some growth on the inboard side. Though there is little or no growth between these areas, that portion must have been submerged by virtue of lying between those two submerged areas:

Outboard leading edge marked up copy
Fig. 10. The outboard end of the leading edge. For full resolution image, click here.


This view offers more detail of the inboard end of the leading edge. Growth is quite heavy, though only the tips of barnacle clusters extend outward beyond the plane of the leading edge:

Leading edge inboard marked up copy
Fig. 11. The inboard end of the leading edge. For full resolution image, click here.


It’s fairly self-evident that the top surface was immersed:

APTOPIX Missing Malaysia Plane
Fig. 12. The top surface. For full resolution image, click here.


As well as the trailing edge, where the flaperon was evidently severed along the line of a transverse spar. Here we see the top edge, along with some of the bottom:

Malaysia Confirms Debris Is From Malaysia Flight MH370
Fig. 13. The trailing edge. For full resolution image, click here.


Here’s the rest of the bottom part of the trailing edge:

Aft bottom edge copy
Fig. 14. Another view of the trailing edge. For full resolution image, click here.


Now let’s look at the inboard end cap.

French gendarmes and police inspect a large piece of plane debris which was found on the beach in Saint-Andre, on the French Indian Ocean island of La Reunion
Fig. 15. The inboard end cap. For full resolution image, click here.


Onward to the object’s final face, the bottom surface. It does not exhibit the same degree of encrustation as we see on the top side. In Figure 16, below, we see the underside of the flaperon with the trailing edge at top. We’ve already noted the presence of barnacles on the bottom of the trailing edge and the bottom of the inboard end cap. We haven’t seen as much yet of the bottom of the outboard end cap, so I’ll focus on that area in this image:

MH370 search: Debris found on Reunion being sent to France
Fig. 16. Bottom surface, outboard end. For full resolution image, click here.


Barnacle growth is much less profuse on the bottom than it is on the trailing edge, but there are enough individuals present on this portion to suggest that the entire bottom edge of the outboard end cap must have been submerged. So, therefore, must have the entire underside. Note that the numbers “1,” “2,” and “3” correspond to the clusters of barnacles marked likewise in Figure 9.

How did the Reunion flaperon float?

The contrast between the Reunion flaperon and other floating debris we’ve looked at is quiet stark. The piece that came off MH370 does not have a Lepas line. There is no significant area that could have protruded above the waterline. The entire surface resembles the deeply submerged areas seen on the other flotsam.

This fact evidently did not escape the French investigators who took custody of the piece. On August 21, the French news outlet La Depeche reported in August that “According to a Toulouse aeronautics expert who requested anonymity, the element of the wing would not have floated for several months at the water’s surface but would have drifted underwater a few meters deep.” Similarly, an article that ran in Le Monde on September 3, 2015, stated that “Les études de flottabilité du flaperon ont quant à elles confirmé que le débris flottait légèrement en dessous de la surface de la mer.”: “Studies of the flaperon’s flotation have… confirmed that the debris floated slightly below the surface of the ocean.”

This seems a reasonable assessment to Venn, based on the distribution of barnacles visible in photographs of the flaperon. “I think it was probably floating just barely subsurface,” she says.

This presents something of a paradox. “It is very hard to build something that will float slightly below the surface,” wrote David Griffin, an oceanographer with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), in an email. “The probability that an aircraft part does this is miniscule. The only way it can do this is if some of the object breaks the surface. If it does not break the surface AT ALL it must sink.”

One could just about imagine that, by sheer good luck, the flaperon might have wound up taking just enough water to give it an overall density almost exactly that of seawater, so that it floated with perhaps a minuscule portion above the water. But such a situation would not be stable. Objects floating with only very slightly positive buoyancy can be pushed below the surface by the action of large waves, says Sean Kery, a hydronamicist at CSC Defense Group who has extensive experience modeling the impact of waves on floating objects. If storm waves push down an object being held afloat by open air pockets, the increase in depth would cause those pockets to shrink, reducing their buoyancy and causing the object to sink further, a phenomenon well-known by recreational scuba divers, who must learn to keep inflating their BCDs as they descend. Of course, without an active compensation system like a BCD a flaperon that was neutrally buoyant at the surface would become negatively buoyant below it.

What’s more, even if an object did manage to float just barely touching the surface, it would eventually sink lower as marine life accumulated. “Things never stay statically neutral,” says oceanographer Curtis Ebbesmeyer. “It’s a dynamic situation. It has to do with infiltration of water, it has to do with the weight of barnacles growing on it.”

Thus, the distribution of barnacles on the Reunion flaperon is difficult to understand. Because they are found all over its surface, the flaperon must have settled into the ocean with a buoyancy exactly identical to that of seawater. And somehow it remained there, floating in a stable manner. Yet this is close to physically impossible.

How could the flaperon have remained underwater?

Given the seeming impossibility of the flaperon floating free across the ocean while submerged, is there another way it might have arrived in its current barnacle-encrusted condition? Since the piece must have been completely underwater, it might have become colonized on the sea bottom. That explanation, however, is problematic. The 7th arc passes through an area of the southern Indian Ocean that is thousands of feet deep. In order to have become colonized by Lepas on the seabed, it would have had to have floated thousands of miles to shallower water, sunk, then refloated to the surface and almost immediately been washed ashore. Also, while Venn says that while she has collected specimens from as deep as 100 meters, “that was not on the bottom or anywhere close to the bottom. It was simply 100 meters below the surface where the ocean was probably more than 5000 meters deep. I have never heard of Lepas colonizing anything on the sea bottom.”

Another possibility is that the flaperon was positively bouyant but remained beneath the ocean surface because it was tethered to the seabed. As it happens, in the past researchers have successfully managed to raise Lepas on substrates anchored offshore. In Yoichi Yusa’s experiment noted above, he collected Lepas specimens growing on pieces of driftwood and floating plastic and attached them to tethers in a bay in Japan. There he monitored their progress as they grew over the next month and a half.

The view of the flaperon seen in Figure 17, below, might provide evidence of how the tethering was accomplished. On the inboard edge of the upper face one can observe a peculiar strip where the surface appears considerably less weathered than the surrounding area:

APTOPIX Missing Malaysia Plane
Fig. 17: A mysteriously clean rectangle


When this was first pointed out to me I  figured it had to do with the missing piece of rubber gasket along the inboard edge of the top surface, which might have been knocked off by contact with a reef. But now that I look closer I see that it isn’t actually that. I’ve marked the “white area” on a photo of a new flaperon below (image reversed to make a left flaperon look like a right one):

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Fig. 18: The location of the mysteriously clean rectangle depicted on an intact flaperon.


It seems that something was clamped to the “lighter patch” that isn’t normally attached to a flaperon, and which was detached after the part spent some time in the ocean. Since it’s hard to imagine this happening without human agency, perhaps it was part of a tethering/untethering operation. Perhaps an anchor line was attached there.

Duration of immersion

Up until now, it has been assumed that the flaperon was deposited somewhere along the 7th arc soon when MH370 impacted the southern Indian Ocean on March 8, 2014. If it was actively tethered to the seabed, obviously, this timeline is no longer relevant. Instead, we can turn to the barnacles to provide some indication of the likely duration of the flaperon’s immersion.

“Assuming they have enough food, and the temperature is good, barnacles will follow a steady growth progression,” Venn says.

The clock starts running the moment the flaperon hits the water: So long as the water is warm enough, Lepas will begin to colonize an object almost immediately. (Yachtsman who make long oceanic passages report that after spending a few weeks heeled over on a single tack a section of hull that is normally high and dry can pick up a colony of Lepas; Venn says she has seen cyprids attach to material as ephemeral as floating paper bags.) While the precise growth rate depends on water temperature and food availability, a rough notion of these parameters is enough to yield a ball-park figure for how long immersion has continued. Earlier this year, Venn co-authored a paper in which she and her colleagues ascertained that a human body found floating off the cost of Italy must have been in the water at least 65 to 90 days, based on the size of the Lepas barnacles growing on its clothes.6

We can do something similar for the barnacles on the flaperon, using the Mayotte boat as a reference. Since both traveled through a similar stretch of the southern Indian Ocean, their growth rates should be in the same ball park.

By comparing features on the flaperon to reference objects of a known size (e.g., the rear door of a Gendarmerie Land Rover Defender in Figure 16) we can estimate the capitulum lengths of the largest barnicles on the flaperon. They turn out to be approximately 2.3 cm.

Applying the same technique to the Mayotte barnacles yields capitulum lengths of about 3.5 cm.

Yusa’s paper on Lepas growth rates states that “Individuals <5 mm long (mean ± SE = 3.09 ± 0.19 mm) grew rapidly, reaching 12.45 ± 0.54 mm on day 15 (Fig. 2). After that, their growth slowed and finally reached 16.26 ± 0.49 mm on day 42.”

The Lepas anserifera that Yusa studied are somewhat smaller than the Lepas anatifera that predominate on the flaperon, but if we use Yusa’s growth rate as a conservative lower bound, and suppose that the largest flaperon barnacles were 16.3 mm at day 42 and grew at 0.1 mm/day thereafter, that means it would take them another 67 days to reach 2.3 cm, for a total growth time of 109 days, or about four months.

If they proceeded to grow at 0.1 mm for the following four months, that would take them to 3.5 cm, which is what the Mayotte barnacles achieved.

Interestingly, when I asked Yusa via email how long it seemed to him that the colony had been growing on the Reunion Island flaperon, based on photographs I sent, Yusa answered: “I would guess that they had been there for a short time (between 2 weeks and a few months).”

Venn’s seat-of-the-pants estimate was “less than six months.”


Photographs of barnacles living on the MH370 flaperon discovered on Reunion Island, combined with expert insight into the lifecycle and habit preferences of the genus Lepas, suggest that the object did not float there from the plane’s presumed impact point, but spent approximately four months tethered below the surface.

UPDATE 10/10/15: Could the distribution of barnacles be explained by continual flipping?

Since I posted this piece yesterday evening, a number of people have suggested that perhaps the flaperon flipped over every few hours, allowing barnacles to survive on both sides. Such a scenario might also explain why the density of Lepas is rather low compared to that seen on other objects. It faces two difficulties, however.

First, the flaperon is broad and flat, and once its inner cavities were filled with water it would weigh thousands of pounds. With only a few inches of freeboard in even the most optimistic scenarios, it would be very resistant to being flipped — much more so than, say, the fridge, which nonetheless clearly floated in a stable manner. Even if it were fairly easy to invert, high waves and wind would be required to do so, which would mean that flaperon would have had to have spent a year or more in constant storm conditions. Yet tranquil conditions are actually more normal. “Calm seas are actually pretty common in the stable high pressure cells that more-or-less permanently inhabit the center of ocean basins,” says Hank Carson, who has traveled across the Pacific gathering floating debris. It’s hard to envisage anyhing flipping over a day like this.

Second, the reason that the Lepas line exists is that these animals don’t like to be exposed, even for a few seconds. They can survive close to the waterline, where they are risk being exposed and immersed with every wave cycle, but only a few small outliers attempt it. They are simply not adapted to frequent long-duration exposure, like their relatives who live attached to rocks in the intertidal zone. “I do not think they can survive more than one day above the water,” Yoichi Yusa told me, while Venn says she has seen them live as long as three days. Apart from the physiological stress of being exposed to what to them is a toxic environment, the animals would spend half their time unable to feed. So even if we imagine the essentially impossible scenario in which the flaperon keeps flipping back and forth every few hours, we would not expect to see dense aggregations of mature individuals.

The implications of low settlement density

While we can learn a lot about how long an object has been afloat by the length of Lepas capitula, it’s harder to draw conclusions based on the density with which they settle. Barnacles do not land randomly, like plant seeds, but actively sniff out an object’s surface in the cyprid stage before settling down in the spot they like best. While they prefer living in the shade, they even more prefer cracks and crevices, and dislike a smooth surface. You can see several places on the top of the flaperon where they’ve preferentially settled down into dings and divots. Most of the broad expanse of the upper and lower surfaces they have avoided, most likely because it’s just too smooth and exposed. They especially seem to like the exposed broken honeycomb on the trailing edge, which presumably offers a nice rough surface for holding fast to. Here they are living in quite high density, with some actually growing on top of one another:

(150806) -- THE REUNION ISLAND, Aug. 6, 2015 (Xinhua) -- Photo taken on Jul.29, 2015, shows shells growing on a piece of debris on Reunion Island. Verification had confirmed that the debris discovered on Reunion Island belongs to missing Malaysian Airlines flight MH370, Malaysian Prime Minister Najib Razak announced early Thursday. (Xinhua/Romain Latournerie) (jmmn)

By way of comparison, here’s a shot of the barnacles on the Mayotte motorboat. Their distribution is much more uniform on every surface — here Lepas seem to like everything equally well:


Therefore, I wouldn’t necessarily say that Lepas density on the flaperon is low, but rather that the suitability of the substrate is very heterogeneous.

328 thoughts on “How the MH370 Flaperon Floated — UPDATED”

  1. You could imagine the media frenzy if the French said anything like it? Was the eventual means of flaperon verification ever really published? Exactly what numbers and where – the first lot of serial numbers pertaining to 777 were made public.

  2. Thank you for a great summary and collecting information from many experts.

    I am curious about another, less sensational, possibility, that the flaperon was not floating in the same orientation the entire time.

    One can easily imagine it having two stable positions, on the top and the bottom surface. And if there was air or water trapped inside, it could also lean, with one of the two end caps sticking out of the water. A significant storm or perhaps curious large fish could periodically flip it from one to another of the stable orientations.

    In this way Lepas could grow on any one surface for only a few months before being exposed above water. Note that while there are many colonies, they are not nearly as dense as comparison in Fig 2 and 3., indicating that there was probably not enough time for multiple generations to grow on top of each other.

    A question that perhaps the experts can answer is what happens when the barnacles are exposed slightly above water, while perhaps still being occasionally splashed. Presumably they will stop growing and probably die eventually, but would the capitulum (shells) remain attached for a long time?

  3. Great analysis. What is the buoyancy of the barnacles? If they were attached to an object do they make it less buoyant? In other words do barnacles increase the specific gravity and cause the object to slowly sink? Could it have started at the surface and slowly sunk as barnacles attached?

  4. Congratulations on another amazing piece of analysis, Jeff. It would be fascinating to learn if the French came to a similar conclusion, but will not be publishing it.

  5. Great summary and cudos to publish it.

    Picking up Mikes thinking, that the flaperon might have changed its floating position in the water the following question came to my mind: Assuming the flaperon was colonized early, but environmental factors or its floating position caused the death of the barnacles, would the dead animmals stick to the surface or fall of without leaving a trace?

  6. Leaving aside the tethering possibility for the moment, does not the higher density of barnacles on the trailing edge suggest that it floated trailing edge down? That would seem likely as most of the buoyancy is further forward.

    if the flaperon started its drift in the far south is it possible that it had only been within the range of this species of barnacle for the last few months?

  7. Looking at the clean patch it appears that whatever was attached there was reinforcing the skin at that point as the tear has gone around it, suggesting that whatever it was was in place when the damage occurred.

  8. @Mike, @Paul Power, @Trip, @Dr R, @Retired F4: Thanks for your kind words.

    @Mike: Barnacles exposed above the water generally die after about a day and drop off, though Cindy Venn says she has seen them survive for up to three days. When they go they can leave behind a mark, like a white smudge. The problem with the multiple-orientations idea is that it would result in multiple barnacle-free areas.

    @Chris: You raise two great points. First, without a clear Lepas line it’s difficult to use the barnacle settlement pattern to deduce the orientation of the object they’re living on. While they prefer living in the shade, they even more prefer cracks and crevices, and dislike a smooth surface. You can see several places on the top of the flaperon where they’ve preferentially settled down into dings and divots. They especially seem to like the exposed broken honeycomb on the trailing edge, which presumably offers a nice rough surface for holding fast to.
    Second, that is indeed a reasonable scenario, although it doesn’t seem to fit with the drift models that have been generated for MH370. Here’s one that shows both drift path and water temperature:
    You’ll see that in order for debris to get to Reunion it has to almost immediately move into “yellow” water, which is sufficiently warm for Lepas to begin colonization.

  9. @Trip, I don’t know what the actual specific gravity of barnacles is, but they are heavier than water, and as more and more of them attach, an object will ride lower and lower in the water. This can have a significant effect when you’ve got gobs and gobs of the critters, as on the tsunami skiff in Fig. 1. Given the relatively sparse population on the flaperon they probably would not have had a very big impact.

  10. So, does anything rule out it being still attached to the plane for a time, then breaking off and floating to the island?

  11. @Craig, If it was attached in the deep sea and then broke off, that would explain the young age of the barnacles, but not how it managed to float totally submerged. So yes, that’s ruled out.

  12. Are we perhaps taking the expert’s opinions about barnacle lifestyle and preferences somewhat too literally?

    Jeff Wise wrote above:

    “Looking at the skiff more closely, we see that the upper part of the hull is ringed with a very well-defined boundary below which the Lepas are cheek-by-jowl (orange line in Fig. 2, below). Above that lies an intermediary zone, extending to the waterline (green line), where algae predominate. While some barnacles are visible, they are small and few in number.”

    Doesn’t that describe the whole of the flaperon floating almost totally submerged in a flat attitude? No part of the flaperon would be permanently below the Lepa line, and nowhere do we see a massive accumulation of barnacle that we would expect to see if the flaperon had been tethered below the Lepa line level below the surface.
    Jeff Wise wrote above in the Update:

    “First, the flaperon is broad and flat, and once its inner cavities were filled with water it would weigh thousands of pounds. With only a few inches of freeboard in even the most optimistic scenarios, it would be very resistant to being flipped — much more so than, say, the fridge, which nonetheless clearly floated in a stable manner.”

    Is that correct? The fridge was stable because it had so much buoyancy in excess of its weight. An object with zero or negative buoyancy complety under water does not resist turning over. The flaperon with near-zero positive buoyancy would turn over easily.

    jeffwise posted October 10, 2015 at 7:18 AM: “Barnacles exposed above the water generally die after about a day and drop off, though Cindy Venn says she has seen them survive for up to three days. When they go they can leave behind a mark, like a white smudge. The problem with the multiple-orientations idea is that it would result in multiple barnacle-free areas. ”

    Let’s keep in mind that the flaperon was found on the beach at La Reunion on July 29, transported to Paris where examination began on August 5. Had all the barnacles ‘gone’ by then?

  13. @Dennis: motive could be to create false impression ISAT data is independently corroborated. If so, would fit pattern of fake corroborating evidence presented to us over past 19 months.

  14. On reflection, my comment above about buoyancy is somewhat too general. If the center of buoyancy is different from the center of gravity, a fully submerged body will have a stable orientation and resist change of that orientation, depending on the distance between the center of gravity and the center of buoyancy. If the cavities in the interior of the flaperon are not completely filled with water, the movement of that water inside the cavities must also be considered.

  15. I think its a very important detail, that Jeff Wise is discussing here, when he says, that the air bubbles in a submerged part will kind of deflate or be compressed by the additional pressure of the water column, when taken down the water column by weather and waves. Thats indeed very good science and says, that this flaperon has to tell more than was revealed by the French now.

  16. Regarding ALL theories that rest on the assumption that the flaperon sank to the bottom at some point, even briefly, and then resurfaced later…ALL such scenarios are physically impossible. The honey comb skins could not remain sealed (buoyant) under the pressure of a deep submersion. The cells would collapse and fill with water, causing the flaperon to sink permanently.

  17. I’ve been obsessed with MH370 ever since March 8th 2014. This is my first comment here, been reading your work for a while now @jeffwise Personally this “flaperon” does not look like something that has been lost at sea for the last 19 months.

  18. I think it is important to find out in more detail how long the goose barnacles can survive or at least remain attached under less than ideal conditions.

    An estimate of them falling off after 1-3 days seems too short. There are many pictures of logs, boats washing on shore with many goose barnacles attached and none having fallen off. Its unlikely they would all be photographed within a day of being washed up in a big storm. There is also a number of such reports from UK, so they would spend a number of months in less than ideal water temperature. There are also pictures of round logs that appear completely covered on all sides. Such logs would presumably easily rotate in water.

  19. thank you, jeff, for your continued interest in finding out what happened to mh370. it is very troubling that we have never received a detailed report from the french. have they also been compromised or are they just holding their cards close until they have more proof of something? if enough people continue to ask questions and investigate, perhaps in time we will find the truth.

  20. If the conclusion stands, what would the implications be for the proposed debris path and ocean current modelling?

    It was found that debris would be expected after 12 to 24 months (assuming it would float immediately upon entry in the ocean).

    At first glance, this seems inconsistent with your conclusion, i.e. probable float time of weeks to a few months at most.

  21. The French investigators are holding back because they are still treating it as deliberately action by someone that wanted it to look like an accident.

  22. @Hendrik Beijeman, Right, the implication of this barnacle analysis is that the flaperon did not float after MH370 impacted the water. Indeed, the implication would be that the plane didn’t hit the ocean at all.

  23. @Sarah, It is indeed troubling, I hope that if public focus shifts to the troubling evidence presented by the barnacles then the authorities will feel the need to be more forthcoming.

  24. @Gysbreght – Seeing your photo made me chuckle. I drafted a message back in August (but didn’t post it) that proposed the flaperon floated just like the model in your photo.

    @Jeff – Wouldn’t this orientation support the barnacle colony:
    Almost flat, top surface down with the outboard end and trailing edge fully submerged with just a portion of the leading inboard edge above the waterline? Also, couldn’t cold water due to the approaching winter have delayed the onset of barnacle growth for many months? Perhaps. the flaperon was caught in a cold water gyre and wasn’t released to travel north until January?

  25. @Mike, Excellent points. I think you’re right, they don’t drop off after 1-3 days, but they die, and presumably fall off at some point after that. As I’ve been researching this out, I’ve come to realize that a lot of things float in the water that Lepas can live on, but having very different dynamics: a tethered buoy for instance is going to react to waves differently from a golfball-sized piece of pumice. Some substrates, like wood, can absorb water and provide a more amenable habitat when temporarily exposed than bare metal. Frankly I’m going to have to keep reporting this out. As for the log, it would indeed be problematic for that analysis I’ve prevented if it really has Lepas going all the way aorund; we’d really need to see the underside.
    What often happens with spherical or near-spherical objects like coconuts, I’m told, is that once marine life starts to settle on it, wherever they start to grow becomes heavier and ultimately the thing does develop a preferential orientation.

  26. @Lauren H, @Gysbreght: From what the Lepas experts are telling me I don’t think you can have whole edges out of the water like the soap in Gysbreght’s picture; they just don’t like to live above the waterline. I think an orientation that Lauren suggests is the most likely, in fact the only conceivable one, if my understanding of Lepas settlement patterns is correct: a couple of inches of the aft, inboard, lower corner could stick out of the water. Probably starting with a situation like that shown in Gysbreght’s picture, with one whole edge submerging, then another and another, until you’re left with just the bottom inboard edge out of the water, then 9/10 of that submerges as well so that only the final corner remains sticking ito the air. The three problems I see with this are: a) Lepas don’t seem to like to be that close to the waterline b) there’s no other indication of a waterline such as algae c) to float with such a tiny amount exposed would require a specific gravity so close to seawater that it would be right on the cusp of negative buoyancy; yet the closest barnacles to it aren’t particularly small, so the implication is that it would have floated this way stably for at least four months.

    As to your question about the gyre, Lauren, based on the drift simulations I’ve seen, if the flaperon came off near the current search area and remained swirling in cold water — which is certainly possible — it wouldn’t have time to then make it across the Indian Ocean to Reunion.

  27. The object shown in my post is a flat plastic box with water, colored with a few drops of Cabernet Chauvignon. Here it is shown almost empty floating upright:

    When I filled the box to the rim and put the lid on, a small bubble of air remained because of the corrugations in the lid:

    add hypertext prefix:

    The first thing I checked was how easy it is to flip the box over. That doesn’t require much force. The box almost floats in any orientation, except that when released vertically, it very slowly rotates and ends up almost flat, either upright or upside down as shown in the pictures.

    But the real point is that if you push the high corner down, the bubble moves to another corner and the box remains floating with that corner up.

  28. A tentative theory about the “lighter patch”.

    As I wrote earlier, I attribute the discolouring of the flaperon skin to combustion products in the engine exhaust, and something was clamped to the “lighter patch” while the flaperon was attached to the airplane. Wondering what could have been attached and using some imagination produced the following hypothesis.

    Jeff’s figure 18 shows a flexible seal on the upper inboard edge of the flaperon extending from the hinge bracket backwards until near the trailing edge. The seal looks like having a tubular cross-section with a flap for attaching it to the upper skin of the flaperon that protrudes beyond the inboard end rib. How was it attached? Perhaps it was originally glued to the skin extension, which also looks to be quite thin and of composite material, perhaps no more than the outer layer of the honeycomb sandwich skin. The seal is subject to wear, and probably was replaced more than once in the 12 years of service of the airplane, rendering the bond between sealflap and skin less durable. A fix was developed, that involved sandwiching sealflap and skin between two metal strips along the length of the seal, held together by hollow rivets, like the ones you find on jeans trousers.

    When the inpact with the ocean broke off the rear 30% of the flaperon, it took the whole seal and metal strips with it, and most of the skin extension sandwiched with it, except for the stub with the “lighter patch” of skin. That stub remained because it was reinforced by an angled strip below it attached to the rib.

  29. @Gysbreght – I agree that the flaperon would have turned over easily. It doesn’t matter how much it weighs, if its overall SG was near to that of seawater it would follow what the water around it did. If, for instance, it found itself on the front of a wave about to turn over it would turn over with it. Even non-breaking waves have a kind of circular, rolling motion inside them so I think it would have moved around quite a lot.

    @all – I was starting to wonder if the dark, roughly circular blotches, mainly on the inboard third the upper side, were the attachment points of barnacles that had died and fallen off. I know they are supposed to leave a white mark but I was thinking that perhaps these marks formed a substrate more easily colonised by algae (or perhaps bacteria?), hence the dark colour.

    However, anyone who has done a bit of mucking about in boats will realise that algae can grow on pretty well any surface from polished GRP to stainless steel and even anti-foul coatings. So after many months in the water, where are all the algae? There are plenty of algae that grow in the littoral zone so why are they so sparsely present on the flaperon? Look at figure 3b in Jeff’s piece above. There is a good coating of them on the upper part of the buoy, which, like the flaperon, presumably was awash while floating, although there is that clearer patch just above the Lepas line that I don’t understand.

    Incidentally, in Fig 17 there is a straight line that runs in an inboard – outboard direction and lines up with Jeff’s top left arrow and appears to continue on the clean patch. The line of a spar perhaps? But why should it affect whatever that is on the surface?

  30. chris posted October 12, 2015 at 10:48 AM: “Incidentally, in Fig 17 there is a straight line that runs in an inboard – outboard direction and lines up with Jeff’s top left arrow and appears to continue on the clean patch. ”

    Good catch! It is probly where the top surface of the retracted flaperon meets the upper skin of the wing:
    There’s another line further forward about halfway to the leading edge.

  31. @Gysbreght – The inboard flap in the movie has such a line on it. However, to my eye the flaperon does not appear to retract quite deeply enough into the wing for it to have a line in the position of the one in Fig 17.

  32. @Gybreght – PS, I think the other line you point out looks in about the right place for what you suggest.

  33. Jeff, a nice piece of investigative journalism, one of the best to date IMO.


    “Photographs of barnacles living on the MH370 flaperon discovered on Reunion Island, combined with expert insight into the life cycle and habit preferences of the genus Lepas, suggest that the object did not float there from the plane’s presumed impact point, but spent approximately four months tethered below the surface.”

    Ok, so tethering may be valid, but tethered to what may I ask? It certainly wasn’t tethered to the sea floor at the presumed impact point due to pressure dynamics on the honeycomb structure.

    Your independent expert advised you:

    “ Venn says that while she has collected specimens from as deep as 100 meters, “that was not on the bottom or anywhere close to the bottom. It was simply 100 meters below the surface where the ocean was probably more than 5000 meters deep. I have never heard of Lepas colonizing anything on the sea bottom.””

    If your conclusion is to stand, then it must have been tethered to something at much lower levels than at the presumed impact point.

    Could it have been tethered to the wing or section thereof, at some substantial depth where lepas will not colonise, only to break free due to some deep water condition experienced?

    This would contradict any flutter or release on impact theory. To my mind, Boyle’s Law would indicate any deep tethering below colonisation level would not allow the object to re float even if it broke free. Any buoyancy would be lost by >11 atm (100M).

    If tethering was an option, it had to be at substantially higher water levels.

    In reply to your lighter coloured patch on the inboard edge you write:

    ” Since it’s hard to imagine this happening without human agency, perhaps it was part of a tethering/untethering operation. Perhaps an anchor line was attached there.”

    When you look at the refurbed flaperon, you will note there is an extended ledge from the vertical end face along the whole of the top surface and a partial one on the lower edge. Both of these are missing (the top one from the riveted joint rearwards). You can see the fracture zone on the top surface where this ledge once fitted and how it mates with the missing trailing edge. These missing pieces went awol along with the trailing edge. I cannot explain the difference in colouration at the riveted join where a ledge once stood with any authority. It could be as simple as a construction adhesive between the joints.

    The Kevlar Cat barnacle buildup is interesting. It is highly colonised. These surfaces on which they are attached to are as smooth as the control surfaces of a flaperon or the deep ocean buoy. So I believe surface texture can be discounted to a degree. You say:

    “I wouldn’t necessarily say that Lepas density on the flaperon is low, but rather that the suitability of the substrate is very heterogeneous.”

    I would. For whatever reason, the density is far lower than the 3 other examples you present. The cat’s surface is as smooth as a flaperon’s……..control surface. It may come down to one being a painted surface, the other not. Could it not simply be that the flaperon floated, be it partially or submerged and untethered, to its final resting place, with little barnacle build up due to inherent buoyancy and anti fouling properties of the surface treatment used? – Occam’s??

    Again, like all things MH370, the flaperon provides nourishment for discussion, but without official release of detailed technical findings.

  34. @Gysbreght

    I don’t see what the missing trailing edge has to do with it. I see the contact point on both videos as being where the airfoil is at its thickest or very close to that.

    I see the soot on the inboard flap. I think I see some on the inboard end of the flaperon too, in a similar region to the dark marks on the Reunion one, though why it would end up in that mottled pattern on the latter is anyone’s guess I suppose.

  35. @Jeff – In your fig 2 and fig 3b there are a few barnacles above the Lepas line. Are these a different species perhaps or are some individuals more tolerant to the conditions higher in the column? They certainly look smaller than the main population. Whatever, could this give a clue to the smaller growing, sparser population on the flaparoony?

  36. chris posted October 12, 2015 at 12:34 PM: “I don’t see what the missing trailing edge has to do with it. ”

    It needs to be considered when comparing a chordwise position on a complete flaperon to that on a damaged one.

    Somewhat earlier in the last video, at about 7:30, the flaps are in an intermediate approach position and you can just see the top ends of the vertical parts in the rectangular arrangement of seals aft of the nose section, and the rearmost of those is where your line is.

  37. @ Gysbreght – I’ve been looking at the ‘soot’ again. I’m beginning to think it looks more like lubricating oil.

  38. Very interesting and thought provoking discussion.

    Is it possible that the part has been ‘cleaned’ or had barnacles removed during handling by the people who initially found it?

  39. @ Sharkcaver – I think some of the lower bracket is still there. At least the tapered portion is, then it merges with the mangle of the trailing edge.

    It looks like the edge of the skin we can see from the clean patch forward is more or less intact. If you look at the picture of the pristine flaperon you will see that the top gasket protrudes further than this edge so I assume the top bracket must do so as well. It is not visible from above, but if you look at it end-on (Jeff’s fig 15) you will see something like a section of the bracket having been bent downwards. Maybe it’s not that but it looks like it could be. Odd thing is, the rear end of it coincides with the back end of the clean strip. From there back toward the trailing edge all of the bracket is missing, having detached along the line of the ‘end-cap’

  40. @Gysbreght – I think you are correct. What confused me was that there appeared to be a third vertical on the video flaperon that does not appear on the picture of the intact one. Looking again at the Reunion flaperon I think I can see where this third vertical part was attached. (a bracket for another gasket?)

    Also on the video I don’t see a top gasket on the inboard end but I do on the outboard end.

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