Archive for March, 2025

Is Armada 7806 Returning to the MH370 Debris Field?

by Victor Iannello Posted: Sunday, 3/9/2025

After a day in port in Fremantle, Australia, to refuel and resupply, Armada 7806 is headed back to the MH370 search area. Based on an average speed of around 10 knots, it should reach there around 02:30 UTC on March 11.

There is a sign that this phase of the search will be shorter than expected: Armada 7806 is self-reporting through Automatic Identification System (AIS) marine tracking that its destination is Cape Town, South Africa. As this is considerably further from the search area than Fremantle, it would make no sense to travel to Cape Town and then return to the search area. A leg to Cape Town would also limit the time that Armada 7806 could spend in the search area, as the port-to-port time is typically less than four weeks.

So why might Armada 7806 be returning to Cape Town after visiting the search area. I offer three possibilities:

  1. During the last phase, something resembling a debris field was detected. If so, Armada 7806 might travel to this spot, launch one or more AUVs, and get better data, including possibly images. After a short time gathering this data, it might travel to Cape Town before it is reassigned a new mission. Another vessel with ROV capability would then be assigned to better document the debris field and perhaps recover some wreckage.
  2. There are ongoing contractual issues between OI and Malaysia and the search will be cut short even if no debris field is detected.
  3. The AIS destination is not correct, either due to an error or due to misdirection.

With the recent announcement by Malaysia saying that the search contract with Ocean Infinity is approved and the signing is imminent, it reduces the probability of (2). Once the contract is signed, we can almost completely eliminate this possibility.

If (3) is correct, we would expect that Armada 7806 would remain in the area for a number of weeks to collect more data and then return to Fremantle. If (1) is correct, the time in the search area will be short. So the length of time that Armada 7806 remains in the search area will tell us a lot.

It is difficult to assign relative probabilities to these three scenarios. Perhaps it is confirmation bias that I believe that (1) is most probable. In any event, we’ll know more in the coming days.

Steep Slope

We can zoom into where Armada 7806 is headed to see why this area might be interesting. Presently (and this could change), Armada 7806’s course is towards a steep slope that was searched with AUVs during the last phase of this search. This steep slope also lies within the areas scanned previously by GO Phoenix using a towfish during the ATSB-managed part of the previous search effort. Parts of this slope were also previously scanned by Ocean Infinity with the vessel Seabed Constructor and its team of seven AUVs. A return to this area once again highlights the difficulty in scanning terrain with steep slopes and other uneven topography, even with AUVs.

The part of the steep slope that seems to be the target is part of the same slope that we designated the High Priority Search Area (HPSA), but further south along that slope. At the time we identified the HPSA, we were not aware that so much more of the slope was not adequately scanned during OI’s last search. If the debris field is truly along this slope, our recommendation to fill-in the low quality data near the 7th arc before extending outwards from the arc was accurate. We said:

As the a) final BFO values, b) the lack of IFE log-on, and c) the end-of-flight simulations all suggest an impact close to the 7th arc, a high priority should be to scan the areas closest to the 7th arc that were either never scanned or have low quality data before searching new areas further from the 7th arc. However, with pilot inputs, it is possible that MH370 glided after fuel exhaustion beyond the areas that were previously scanned. Therefore, searching wider along the 7th arc should also be part of the search plan if areas closer to the 7th arc are unsuccessful in locating the debris field...A steep slope to the south of where UGIB predicts MH370 crossed the 7th arc happens to lie along the extended path of the reconstructed route, and much of this slope remains unscanned. For this reason, the unscanned area surrounding S34.52 E93.84 should be designated a High Priority Search Area.

Although we are speculating about what might take place next based on very limited information, the next several days could prove to be very interesting.

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New MH370 Search Continues

by Victor Iannello Posted: Tuesday, 3/4/2025

Ocean Infinity (OI) has completed the first phase of its subsea search for MH370 in the Southern Indian along the 7th arc in the Southern Indian Ocean (SIO). As expected, Armada 7806, with its fleet of three autonomous vehicles (AUVs), is searching in the vicinity of the area proposed by OI in March 2024, generally between 34S to 35S latitudes. Armada 7806 is currently in port at Fremantle for refueling and resupplying. It is expected that the turnaround will take around a day, and that Armada 7806 will return to the 7th arc for the second phase of the search.

We know approximately what areas were searched based on the position of Armada 7806 as deduced by AIS reports transmitted via satellite and made available to the public via various marine tracking sites. However, the exact locations searched depend on the track followed by the AUVs after they are launched from the ship during their “sorties”, and this is unknown. Because launches and recoveries while the Armada 7806 is moving slowly or stopped, some additional information can be gleaned by the ship speed.

The figure below shows more details of the search area. Shown in the figure is the sonar data from the first search managed by the ATSB as contracted to Fugro and GO Phoenix (mixed brown shading), the outline (yellow) of the previous search conducted by OI using Seabed Constructor and its team of seven AUVs, and the outline (red) of new areas that OI proposed to search in March 2024. The tracks of Armada 7806 are shown by the circles and connected lines (purple), where the circles are representative of hourly position reports. Where the circles are clumped is indicative of either a launch or recovery of an AUV, which gives us some insight as to the areas searched.

The first location searched was the area we previously designated as the High Priority Search Area, which lies due south of where MH370 was estimated to have crossed the 7th arc, as presented in UGIB 2020. This lies at the border of where OI conducted its previous search. Other areas searched by Armada 7806 were either previously searched by the ATSB or OI. In some cases, Armada 7806 is searching in an area previously searched by BOTH the ATSB and OI.

The reason for re-searching these areas is apparent from the figure below, which includes the terrain features from bathymetry data and shows the spots in which the ATSB sonar data is poor quality, ambiguous, or missing (so-called “data holidays”), depicted as olive-green areas with white outlines. It is apparent that the search so far has focused on “filling in” the areas missed by previous searches, in particular where the terrain was challenging due to steep slopes. Although the AUVs have better ability to follow terrain contours in comparison to the towfish vehicles used by the vessels contracted by the ATSB, the steepest of slopes also present challenges to the AUVs.

Discussion

The search strategy to date is to progressively eliminate large areas that have the highest probability of finding the MH370 debris field. In our opinion, it makes sense to completely eliminate the areas closest to the 7th arc before proceeding outward from the 7th arc into areas not previously searched. The final BFO values at 00:19:29 and 00:19:37 suggest that at these times, MH370 was in a progressively steep descent of around 0.7g downward acceleration. It is possible that the pilot recovered from this dive and glided further from the 7th arc. After infilling the previous data, the search will likely continue into the new areas proposed by OI, which would at least partially consider the dive-glide scenario. Progressively eliminating large areas of seabed is more sensible than jumping between hotspots. Even the High Priority Search Area we recommended only represents an area that we believe has higher relative probability than other areas, but cannot considered to be a “high probability” area because of the many assumptions that were required to reconstruct the UGIB 2020 path.

Finally, we consider the search recommendation presented in Ulich and Iannello (2023), which included the provision for searching outward from the 7th arc to account for a 70-NM glide. This is shown by the black racetrack below, and includes most of the area proposed by OI to search. This would extend past the 15,000 km2 represented by the search area OI proposed in March 2024 (red outline). It would also include the search area recommended by Blely-Marchand, which surrounds 35.6°S, 93.1°E.

It is unclear whether OI will search other areas if the search in this area is unsuccessful.

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