Archive for February, 2018

MH370 Search Update – Feb 16, 2018

Status of current underwater search. (Click on image to enlarge.)

Recent Activity

After a short stop in Fremantle for to re-fuel, re-supply, and change crew, Seabed Constructor, operated by Ocean Infinity, is back searching for the wreckage of MH370. Ocean Infinity is under contract with Malaysia to use its team of eight autonomous underwater vehicles (AUVs) to scan the seabed in the Southern Indian Ocean (SIO) in search of wreckage from the aircraft. Under the terms of the contract, Ocean Infinity will only be paid if the wreckage is found. The search is occurring in multiple six-week long “swings”, of which the first swing has been completed, and the second swing is just beginning. Subsequent swings will also require a stop in Fremantle for servicing.

For the first swing, Ocean Infinity began by searching the 25,000 sq km of seabed that ATSB and CSIRO have designated as the priority area (shown in white in the figure). So far, Constructor has scanned about 7,500 sq km of seabed, including 5,000 sq km within the priority area that was designated by CSIRO as the “primary area” (solid white). There remains about 20,000 sq km of the priority area that is unscanned (translucent white). Beyond that is the extended search area, which reaches to about 29S latitude along the 7th arc (translucent green), and is expected to be searched at a width of +/- 25 NM from the 7th arc. Under ideal conditions, the eight AUVs are capable of scanning about 1,200 sq km of seabed each day. Recognizing the possibility of weather and operational constraints,  a more realistic expectation might be about 25,000 sq km per swing. However, until Ocean Infinity gains more operational experience, it is difficult to predict what scan rates are realistically achievable.

With the sparse and imprecise evidence we have, it is impossible to assign a high level of certainty to any impact site, as the satellite data and the drift models allow a broad range of possibilities. So, it becomes a numbers game–the more area searched, the higher probability of finding the wreckage. However, within that broad range, there are some “warm spots” that are based on assumptions about navigation inputs and other evidence.

What We Know So Far

In the previous post, I estimated the probability of finding the wreckage as 67%, assuming all of the priority and extended areas are scanned. (This probability will vary some depending on how far north the search reaches.) Considering that only 5,000 sq km of that area were scanned in the first swing, and assuming that there are equal probabilities within that total area, the probability of finding the debris field within the primary area would be about 4.4%. Considering this low percentage, it should come as no surprise that the wreckage has not yet been found, and we are far from the point of re-thinking the search strategy.

Within the area searched so far, there are three warm spots that CSIRO has designated as priorities, based on satellite images of objects that could have been MH370 debris, and from drift models that estimated the points of impact from the location of these objects. Last August, the highest priority location (CSIRO Priority 1) was described by CSIRO’s David Griffin in these words: We think it is possible to identify a most likely location of the aircraft, with unprecedented precision and certainty. Unfortunately, all three of these locations have now been scanned with negative results. Unless positive news is being withheld, the confidence expressed by CSIRO was unfounded. This is not a total surprise: The objects captured by the satellite images had too much surface area to likely be from MH370, and the location of the potential impact sites were  not consistent with the high speed descent suggested by the final BFO values.

Two other warm spots have been at least partially searched in the first swing. The first is an impact location near 34.7S latitude that Inmarsat derived by minimizing the BFO error. More recently, Bobby Ulich proposed a location near 34.8S latitude that was based on a path of constant true heading (CTH). We should know soon whether or not these warm spots are completely eliminated.

Another warm spot that should be searched during the current swing is based on a great circle path between waypoints BEDAX and the South Pole. I first proposed this path in August 2014, and I still consider it to be among the best possibilities because of the excellent fit of the BTO and BFO data, and because of the simplicity of navigating in the direction of true south. That said, despite the attractiveness of this scenario, we don’t know whether the aircraft was navigated in this manner, so it remains one of many other possibilities.

As shown in the figure above, there are warm spots that reach as far north as 27S latitude that are based on certain navigational inputs. Although the match to the BFO data is not as good for paths ending that far north, the BFO error is still well within what was recorded for previous flights of the 9M-MRO airframe. The drift models also favor an impact point further south than 27S. However, for debris discovered on the beaches of Eastern Africa, there could have been a considerable delay between the time of discovery and the time of arrival near the shore, and this uncertainty reduces the accuracy of the drift models.

In a nutshell, although the previous search swing has eliminated some possibilities, we are still very early in the search process, and it is much too early to draw any conclusions.

Unknown Activities of Seabed Constructor

The figure below from Richard Cole shows the recent behavior of Seabed Constructor. At the end of the last swing, Constructor returned to the outer leg of the primary search area, which had been previously scanned. After following the pattern of a 5-km circle, it retraced what we believe was part of a previous path of an AUV, and then disabled its AIS data, which made it impossible to remotely track. When the AIS was eventually re-enabled three days later, Constructor had left the search area, and was traveling back to Fremantle. What activities occurred during these three days is not known.

Seabed Constructor’s path, as adapted from the work of Richard Cole. (Click on image to enlarge.)

At the start of the search for the current swing, Constructor again returned to the southern end of the outer leg of the primary search area, and seems to be actively searching the seabed in this location. The activities in the current area are likely related to activities that occurred when the AIS was disabled during the last swing.

Some possibilities that have been proposed by others to explain the behavior are:

  • Constructor is re-scanning areas that had poor quality or missing data either because of malfunctioning equipment or challenging terrain
  • There are one or more promising points of interest that are under being comprehensively investigated
  • A search is underway to locate equipment that was lost in the previous swing
  • Some combination of the previous possibilities

Whatever the reason for the unexplained behavior, it is noteworthy that there was no reference to the behavior in either of the last two weekly updates from Malaysia. As Malaysia has two observers on Seabed Constructor, Malaysia is certainly aware of the surrounding circumstances. Malaysia’s decision to omit pertinent information in the weekly reports further erodes the public’s confidence in the Malaysian-led investigation. Credibility is not possible without transparency.

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