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Long-rumored police report of cell tower connection leaks at last — UPDATED


Twitter user @AirInvestigate just tweeted this picture. Thanks to reader Ventus45 for posting the link in comments. This presumable is part of the 1,000-page Royal Malaysian Police report that the Independent Group and others have been sitting on for months.

When Victor Iannello described the contents of this report to me, he implied that the only parts that were interesting were 1) the pages describing the flight simulator hard drive data points in the southern Indian Ocean, and 2) confirmation of the Penang cell-phone tower connection with Fariq’s phone. Apparently there was nothing in the rest of it that suggested any hint of what might have happened during the fateful final flight.

Here I’ve used Google Earth to drop a 32 km radius circle centered on Bandar Baru Air Itam on top of a map of MH370’s flight path taken from the “Bayesian Methods” e-book:


UPDATE 11/12/16: @Airinvestigate has posted a second part of the document on Twitter. He describes it as “parts clipped & redacted.”


Interesting to note that the Malaysian police are on the same page with many of those here in this forum in concluding that the plane was flying in excess of 500 knots and at an altitude of 35,000 to 45,000 feet–very clearly not the behavior of someone looking for an emergency landing spot.


Thoughts on Australia’s New MH370 Report — UPDATED


Earlier today, the Australian Transport Safety Board released a document entitled “MH370 — Search and debris examination update.” Perhaps occasioned by the recent completion of the towfish scan of the Indian Ocean seabed search area, the document updates earlier ATSB reports and offers some intriguing insights into what may have happened to the plane. Some thoughts:

— The first section of the report expands upon an assertion that the ATSB made in an earlier report: that the BFO values recorded at 0:19 indicate that the plane was in an increasingly steep dive. Indeed, the newly published calculations indicate that the plane was in an even steeper dive than previously reckoned: between 3,800 and 14,600 feet per minute at 00:19:29, and between 14,200 and 25,000 feet per minute at 00:19:37. On the lower end, this represents an acceleration along the vertical axis from 37.5 knots to 144 knots in eight seconds, or 0.7g. On the higher end, this represents an acceleration along the vertical axis from 140 knots to 247 knots, likewise about 0.7g. If the plane were freefalling in a vacuum, its acceleration would be 1.0g; given that the airframe would be experiencing considerable aerodynamic drag, a downward acceleration of 0.7 would have to represent a near-vertical plunge, which a plane would experience near the end of a highly developed spiral dive.

— The second section describes end-of-flight simulations carried out in a Boeing flight simulator in April of this year. These tests were more detailed than others carried out previously. Evidently, modeled aircraft were allowed to run out of fuel under various configurations of speed, altitude, and so forth, and their subsequent behavior observed. Thus, the exercise modeled what might have happened in a “ghost ship” scenario. Notably, it was found to be possible for the plane to spontaneously enter the kind of extremely steep dive described in the previous section. This being the case, the report states, the plane “generally impacted the water within 15 NM of the arc.” This is not surprising, considering that the plane had already lost altitude and was plummeting straight downward. This offers a tight constraint on where the plane could plausibly be if the 0:19 BFO analysis is correct.

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Towfish Scan of MH370 Search Zone Completed (UPDATED)


Image courtesy of Richard Cole. Click through for full size.


Search crews in the remote southern Indian Ocean have completed a task so vast and technically ambitious that it once seemed impossible: to scan a three-mile-deep, 120,000 sq km swathe of seabed using a side-scan sonar “towfish” in hopes of finding the wreckage of missing Malayia Airlines 777 MH370. After considerable delay due to mechanical problems and bad weather, the final square miles were scanned on October 11 by the research vessel Fugro Equator. The $180 million project turned up no trace of the missing plane, though searchers did find several long-sunken sailing ships.

The Fugro Equator will next use an AUV, or autonomous sub, to scan selected areas where the rugged seabed topography was too rough for adequate imaging by the towfish. “The total combined area of the spots that will be surveyed with the AUV is very limited, but still required to ensure that no area has been missed,” says Fugro spokesman Rob Luijneburg.

The Australian National Transport Board (ATSB), which is overseeing the search, expects this fill-in work to be completed by the end of February.

The fact that that the Pennsylvania-sized towfish scan had been completed was first noticed by Richard Cole, a space scientist at University College London who has been meticulously logging the search ships’ movements via online tracking services and then posting charts of their progress on Twitter. “At the completion of Equator’s last swing in mid-October the target of 120,000 square kilometers had been achieved, at least as far as my calculations show,” Cole wrote me last week. Both Fugro and the ATSB subsequently confirmed Cole’s observation.

The 120,000 sq km area has special significance in the effort to find MH370, because ministers from the four countries responsible for the search have made it clear that if nothing turns up within it, the search will be suspended. Unless new evidence emerges, the mystery will be left unsolved.

Plans to search the seabed were first mooted during the summer of 2014, after officials realized that metadata recorded by satellite-communications provider Inmarsat contained clues indicating roughly where the plane had gone. At first, investigators were confident that the wreckage would be found within a 60,000 sq km area stretching along the 7th ping arc from which the plane is known to have sent its final automatic transmission. When nothing was found, ministers from the four governments responsible for the search declared that the search zone would be doubled in size.

In December, 2015, officials declared that the search would be completed by June, 2016. In July of 2016, Malaysia’s transport minister indicated that it would be finished by October; weeks later, a meeting of the four ministers pushed the completion back to December. Last week, the Australian Safety Transport Board announded that “searching the entire 120,000 square kilometre search area will be completed by around January/February 2017.”

In an email to me, ATSB communications officer Dan O’Malley said his organization will issue a report on the seabed search once the full scan is completed. Under ICAO guidelines, Malaysia will only be obligated to release a comprehensive final report on the investigation once it has been formally terminated; so far, Malaysia has only talked of suspending the search, not ending it.

The bulk of the work has been carried out by ships pulling a sidescan sonar device on a long cable. This so-called “towfish” uses reflected sound waves to create an image of the sea floor. By sweeping up and down the search zone in much the same way that a lawnmower goes back and forth across a lawn, searchers have been able to build up a comprehensive image of the search area’s bottom.

But, just as a landscaper might have to use a weedwhacker to clean up areas around rocks or stumps, searchers will have to fill in gaps in the scan where underwater mountains, volanoes and escarpments have prevented the towfish from getting a close enough look.

“A total area for search by the AUV is difficult to give because it concerns a number of relatively small spots that all are relatively difficult to reach and in difficult terrain,” Luijnenburg says.

The fill-in work will be carried out by an Autonomous Underwater Vehicle deployed from the Fugro Equator. The Kongsberg Hugin 100 is capable of diving to depths of up to 15,000 feet and can maintain a speed of 4 knots for up to 24 hours before being retrieved by the mothership. Whereas the side-scan sonar of the towfish has a resolution of 70 cm, the AUV’s sonar has a resolution of  10 cm, and so can image the seabed in much greater detail, as well as taking photographs when necessary.

Meanwhile, as the AUV work progresses, a Chinese vessel will deploy an Remotely Operated Vehicle (ROV) to take photographs of targets previously identified as being of interest. The ATSB has stated that none of these targets are “category one” targets, namely those likely to have come from MH370, however. Says Cole, “In the absence of category one targets there must be a list of targets from the sonar search that look the most interesting, so the question is how far down that list they are going to go.”

While the fill-in work must be carried out in order for the work to be declared 100 percent done, little prospect remains that the missing plane will be found in the southern Indian Ocean.

NOTE: This story was updated 10/26/2016 to include comments from Fugro spokesman Rob Luijnenburg.


What If Zaharie Didn’t Do It?


Two men, strangers to one another, go into the cockpit of an airplane and lock the door behind them. They take off and fly into the night. One radios to ATC, “Good night, Malaysia 370.” One minute later, someone puts the plane into a turn. It reverses direction and disappears.

Question: Did one of the men take the plane?

For many, it’s inconceivable that there could be any other answer than “of course.” Moreover, that since the details of the incident suggest a sophisticated knowledge of the aircraft, the perpetrator could obviously only be the man with the vastly greater experience — the captain. As reader @Keffertje has written: “Though I try to keep an open mind to all other scenarios, the circumstantial evidence against ZS simply cannot be ignored.”

For others, blaming the captain without concrete proof is immoral. There are MH370 forums where the suggestion that Zaharie might be considered guilty is considered offensive and hurtful to the feelings of surviving family members. Even if one disregards such niceties, it is a fact that an exhaustive police investigation found that Zaharie had neither psychological problems, family stress, money problems, or any other suggestion that he might be suicidal. (Having broken the story of Zaharie’s flight-simulator save points in the southern Indian Ocean, I no longer think they suggest he practiced a suicide flight, for reasons I explain here.) And far from being an Islamic radical, he enjoyed the writings of noted atheist Richard Dawkins and decried terror violence. And he was looking forward to retiring to Australia. If he was trying to make the Malaysian government look bad, he failed, because in the absence of an explanation there is no blame to allocate. And if he was trying to pull off the greatest disappearing act of all time, he failed at that, too, since the captain would necessarily be the prime suspect.

So did Zaharie do it, or not?

This, in a nutshell, is the paradox of MH370. Zaharie could not have hijacked the plane; only Zaharie could have hijacked the plane.

I’d like to suggest that another way of looking at the conundrum is this: if Zaharie didn’t take the plane, then who did? As has been discussed in this forum at length, the turn around at IGARI was clearly initiated by someone who was familiar with both aircraft operation and air traffic control protocols. The reboot of the SDU tells that whoever was in charge at 18:22 had sophisticated knowledge of 777 electronics. And the fact that the plane’s wreckage was not found where autopilot flight would have terminated tells us that someone was actively flying the plane until the end. But who? And why?

If Zaharie did not do it, then one of the passengers and crew either got through the locked cockpit door in the minute between “Good night, Malaysia 370” and IGARI, or got into the E/E bay and took control of the plane from there.

If we accept that this is what happened, then it is extremely difficult to understand why someone who has gone to such lengths would then fly themselves to a certain demise in the southern Indian Ocean. (Remember, they had the ability to communicate and were apparently in active control of the aircraft; they could have flown somewhere else and called for help if they desired.)

Recall, however, that the BFO values have many problems. We get around the paradox of the suicide destination if we assume that the hijackers were not only sophisticated, but sophisticated enough to conceive of and execute a spoof of the Inmarsat data.

Granted, we are still left with the issue of the MH370 debris that has been collected from the shores of the western Indian Ocean. Many people instinctively recoil from the idea that this debris could have been planted, as a spoof of the BFO data would require. Fortunately, we don’t have to argue the subject from first principles. Detailed physical and biological analysis of the debris is underway, and should be released to the public after the official search is called off in December. As I’ve written previously, several aspects of the Réunion flaperon are problematic; if further analysis bears this out, then we’ll have an answer to our conundrum.


Implications of the JIT’s MH17 report


Last week, the Joint Investigation Team conducting a criminal investigation into the downing of idH17 issued their preliminary findings. Here’s what I think are the main takeaways.

— The findings strongly endorse the work of “open source intelligence” pioneer Eliot Higgins and his group, Bellingcat. In the immediate aftermath of the shoot-down, it was accepted by nearly every pundit and journalist that the missile had been fired accidentally by poorly trained militiamen who had somehow gotten their hands on an SA-11 Buk launcher and had a acquired a target without bothering to first identify it. But by painstaking work and great resourcefulness, the Bellingcat team was able to piece together an extremely convincing timeline, by which the launcher was brought across the border from a specific Russian military unit, was transported under the direction of the GRU (Russian military intelligence), shot down MH17, and was sent back across the border that night. As I’ve written previously, the timeline described by Bellingcat does not fit with the hapless-militiaman scenario very well. As the New York Times reported, “It is unlikely that anyone not connected with the Russian military would have been able to deploy an SA-11 missile launcher from Russia into a neighboring country.”

— While still admiting the possibility that the Buk crew acted on its own, the report shifts the emphasis to the once-unthinkable: that the missile launch was ordered by higher-ups:

…an investigation is conducted into the chain of command. Who gave the order to bring the BUK-TELAR into Ukraine and who gave the order to shoot down flight MH17? Did the crew decide for themselves or did they execute a command from their superiors? This is important when determining the offences committed by the alleged perpetrators.

As the New York Times put it, the JIT has signaled that it intends “to build an open-and-shut case against individual suspects and to diagram the chain of command behind the order to deploy and launch.”

One can just about imagine a wet-behind-the-ears lieutenant, newly trained and sitting nervously in the cab of his Buk TELAR, messing up and accidentally firing a missile at an unidentified target. But it is harder to imagine an experienced senior officer mistakenly giving the order. Indeed, the higher one goes up the chain of command, the less likely that the decision was made without explicit or implicit endorsement by an immediate superior. The implication, then, is that the order to shoot down MH17, if it did come from anywhere, came from the very top.

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Assessing the Reliability of the MH370 Burst Frequency Offset Data


Last week we discussed what we know about the first hour of MH370’s disappearance, based on primary radar data and the first Inmarsat BTO value. Today I’d like to talk about the BFO data and what it can tell us about MH370’s fate.

As longtime readers of this blog well know, the Burst Frequency Offset (BFO) is a type of metadata that measures how different the frequency of an Inmarsat signal is from its expected value. It is an important value to a communications satellite operator like Inmarsat because if the value gets too large, the system will be operating outside its approved frequency limit. One cause of such a change would be if a satellite begins wandering in its orbit, which indeed was the case with MH370. The fact that the Satellite Data Unit (SDU) aboard MH370 did not properly compensate for drift in the Inmarsat satellite overhead is the reason the BFO data contains a signal indicating what the plane was doing.

While each of the BTO values recording during the seven “pings” tells us fairly precisely how far the plane was from the satellite at that time, the BFO data points taken individually do not tell us much about the plane was doing. Taken together, however, they indicate three things:

  1. After the SDU logged back on with Inmarsat at 18:25, the plane took a generally southern course. If we didn’t have the BFO data, we wouldn’t know, from the BTO data alone, whether the plane followed a path to the north or to the south (see above.)
  2. The plane had turned south by 18:40. The BFO value at the time of the first incoming sat phone call at 18:40 indicates that the plane was traveling south.
  3. At 0:19:37 the plane was in a rapid and accelerating decent.

However, as I’ve previously described, if all of these things were true, then the plane would have been found by now. So at least one of them must be false. In the course of my interview with him, Neil Gordon said that the ATSB is firmly convinced that #3 is true, and that as a result he suspects that #2 is not. Specifically, he points out that if the plane were in a descent at 18:40, it could produce the BFO values observed. Thus it is possible that the plane did not perform a “final major turn” prior to 18:40 but instead loitered in the vicinity of the Andaman Islands or western Sumatra before turning and flying into the southern ocean. If this were the case, it would result in the plane turning up to the northeast of the current search area. An example of such a route has been described by Victor Iannello at the Duncan Steel website.

It is worth nothing that such a scenario was explicitly rejected as unlikely by the Australian government when they decided to spend approximately $150 million to search 120,000 square kilometers of seabed. The reason is that it was deemed unlikely that the plane would just happen, by chance to be descending at the right time and at the right rate to look like a southward flight. For my part, I also find it hard to imagine why whoever took the plane would fly it at high speed through Malaysian airspace, then linger for perhaps as much as an hour without contacting anybody at the airline, at ATC, or in the Malysian government (because, indeed, none of these were contacted) and then continuing on once more at high speed in a flight to oblivion.

Well, is there any other alternative? Yes, and it is one that, though historically unpopular, is becoming imore urgent as the plane’s absence from the search area becomes increasingly clear: the BFO data is unreliable. That is to say, someone deliberately altered it.

There are various ways that we can imagine this happening, but the only one that stands up to scrutiny is that someone on board the plane altered a variable in the Satellite Data Unit or tampered with the navigation information fed back to the SDU from the E/E bay. Indeed, we know that the SDU was tampered with: it was turned off, then logged back on with Inmarsat, something that does not happen in the course of normal aircraft operation. It has been speculated that this depowering and repowering occurred as the result of action to disable and re-enable some other piece of equipment, but no one has every come up with a very compelling story as to what that piece of equipment might be. Given the evident problems with the BFO data in our possession, I feel we must consider the possibility that the intended object of the action was the SDU itself.

When I say BFO tampering has been “historically unpopular,” what I mean is that almost everyone who considers themselves a serious MH370 researcher has from the beginning assumed that the BFO data was generated by a normally functioning, untampered-with SDU, and this has limited the scenarios that have been considered acceptable. For a long time I imagined that search officials might know of a reason why tampering could not have occurred, but I no longer believe this is the case. When I questioned Inmarsat whether it was possible that the BFO data could have been spoofed, one of their team said “all Inmarsat can do is work with the data and information and the various testings that we’ve been doing.” And when I raised the issue with Neil Gordon, he said, “All I’ve done is process the data as given to me to produce this distribution.” So it seems that the possibility of BFO spoofing has not been seriously contemplated by search officials.

If we allow ourselves to grapple with the possibility that the BFO data was deliberately tampered with, we quickly find ourselves confronting a radically different set of assumptions about the fate of the plane and the motives of those who took it. These assumptions eliminate some of the problems that we have previously faced in trying to make sense of the MH370 mystery, but introduce new ones, as I’ll explore in upcoming posts.


How MH370 Got Away


One minute after MH370’s flight crew said “Good Night” to Malaysia air traffic controls, and five seconds after the plane passed waypoint IGARI at 1720:31 UTC, the plane’s Mode S signal disappeared from air traffic control screens. As it reached the border of the Ho Chi Minh Flight Information Region (FIR) approximately 50 seconds after that, the plane made an abrupt 180 degree turn. The radius of this turn was so small, and the ground speed so low, that it appears to have been effected via a semi-aerobatic maneuver called a “chandelle.” Similar to a “box canyon turn,” this involves climbing under power while also banking steeply. The maneuver offered WWI pilots a way to reverse their direction of flight quickly in a dogfight.

Chandelles are not a normal part of commercial 777 operation. They would not be used by pilots responding to in-flight fire.

The fact that such an aggressive maneuver was flown suggests that whoever was at the controls was highly motivated to change their direction of flight. Specifically, instead of going east, they wanted to go west.

At the completion of the left-hand U-turn the plane found itself back in Malaysia-controlled airspace close to the Thai border. It flew at high speed (likely having increased engine thrust and dived from the top of its chandelle climb) toward Kota Bharu and then along the zig-zaggy border between peninsular Malaysia and Thailand (briefly passing through the outer fringe of Thai airspace) before making a right-hand turn south of Penang. We know this “based mostly on the analysis of primary radar recordings from the civilian ATC radars at the Kuala Lumpur (KUL) Area Control Centre (ACC) and at Kota Bahru on the east coast of Malaysia; plus (apparently) the air defense radars operated by the RMAF south of Kota Bahru at Jerteh, and on Penang Island off the west coast,” according to AIN Online.

At 18:02, while over the small island of Pulau Perak, the plane disappeared from primary radar, presumable because it had exceeded the range of the radar at Penang, which at that point lay 83 nautical miles directly behind the plane. Then, at 18:22:12, another blip was recorded, 160 miles to the northwest.

The most-asked question about the 18:22 blip is: why did the plane disappear then? But a more pressing question is: why did it reappear? If the plane was already too faint to be discerned by Penang when it was at Pulau Perak, then how on earth could it have been detected when it was three times further away?

One possibility is that it was picked up not by Malaysian radar, but by the Thai radar installation at Phuket. An AFP report from March 2014 quoted Thailand’s Air Marshal Monthon Suchookorn as saying that Thai radar detected the plane “swinging north and disappearing over the Andaman Sea,” although “the signal was sporadic.”

At 18:22, the plane was approximately 150 miles from Phuket. This is well beyond the range at which Penang had ceased being able to detect the plane. What’s more, when the plane had passed VAMPI it had been only about 120 miles from Phuket. If it hadn’t seen the plane when it was at VAMPI, how was it able to detect it when it was 30 miles further? And why just for a momentary blip?

I don’t believe that, as some have suggested, the plane climbed, was detected, and then dived again. As Victor Iannello has earlier pointed out, the plane was flying at around 500 knots, which is very fast, and suggests a high level of motivation to be somewhere else, not bleeding off speed through needless altitude changes.

I propose that what happened at 18:22 was that the plane was turning. Entering into a right bank, the plane would turn its wings temporarily toward the Phuket radar station, temporarily presenting a larger cross section. Then,  when the plane leveled its wings to straighten out, the cross section would shrink, potentially causing the plane to disappear. Read the rest of this entry »


Fascinatingly Mysterious New Flaperon Barnacle Data


Last month Robyn Ironside, the National Aviation Writer at the News Corp Australia Network, published what struck me as an extremely important article in the Daily Telegraph about the work of scientist Patrick De Deckker, who had obtained a sample of a Lepas anatifera barnacle from the French judicial authorities and conducted an analysis to determine the temperature of the water in which the barnacle grew. A snippet:

The same 2.5 centimetre barnacle was used by both French and Australian examiners — but different techniques applied. “For my analysis, I used a laser to create little holes of 20 microns, over the length of the barnacles. In all we did 1500 analyses,” said Professor De Deckker.

Intrigued, I reached out to Ironside, asking if she could tell me more about De Deckker’s work. She very graciously did just that, and shared this extremely interesting nugget, a verbatim quote from De Deckker:

The start of the growth was around 24 degrees (Celsius) and then for quite some time, it ranged between 20 and 18 degrees (Celsius). And then it went up again to around 25 degrees.

This is surprising. The graphic above shows the water temperature in July 2005, which I take to be a rough proxy for the water temperature in March 2014. (I would be extremely grateful if someone could extract granular sea-surface temperature maps for March 2014 to July 2015 from NASA or NOAA databases available online.) It shows that the waters in the seabed search area are about 12-14 degrees Celsius. To find 24 degree water would mean trekking 1000 miles north, above the Tropic of Capricorn.

It has long been known that Lepas anatifera do not grow in waters below about 18 degrees Celsius, and that in order to begin colonizing the flaperon (if it began its journey in the search zone) would have had to first drift northwards and wait for warmer months and warmer latitudes. What’s peculiar is that this particular Lepas would have to have waited a good while beyond that, until the flaperon arrived in water six degrees above its minimum. As I’ve written before, Lepas naupali are common in the open sea and in general are eager colonizers of whatever they can glue their heads to.

Peculiarity number two is that after this period of initial growth the flaperon then found its way into significantly colder water, where most of its total growth took place. What’s weird is that every drift model I’ve ever seen shows currents going through warm water before arriving at Réunion. Where the heck could it have gone to find 18-20 degree water? And how did it then get back to the 25 degree waters of Réunion Island, where it finished its growth?

I’m frankly baffled, and am appealing to readers to ponder historical surface temperature data and drift models to help figure out what kind of journey this plucky Lepas might have found itself on.



Trailer for Gringo: The Dangerous Life of John McAfee

Catch the full documentary on Showtime starting September 24.


Commentary on Neil Gordon Interview


Today I’d like to discuss some of the implications of what DSTG scientist Neil Gordon said in the course of the interview I published yesterday.

In particular, I’d like to look at what he told me about the ATSB’s interpretation of the 0:19:37 BFO value. Essentially, Gordon assures us that the experts have looked at what the manufacturers know about how these boxes work, and the only interpretation they can come up with is that the BFO value was the result of a very steep rate of descent–specifically, 5,000 fpm at 00:19:29 and then 12,000 to 20,000 fpm at 00:19:37. This is got a gentle deterioration; it’s accelerating at about 1/2 g, so that in another 8 seconds, at that rate, the descent will be at 19,000 to 35,000 fpm, that is to say going straight down at 187 to 345 knots. Remember that the plane had already been losing speed and altitude for five to fifteen minutes before the second engine even flamed out, and losing more altitude in the subsequent two minutes before the 00:19:29 ping was logged. Thus, both velocity and acceleration point to a situation in which the plane will be hitting the surface in short order. Bearing in mind that the plane would be in a spiral dive if unpiloted, I can’t see how it could have traveled more than 5 nm from the last ping, let alone 15nm, let alone 40 nm. It would have hit soon, and it would have hit hard.

One possible explanation would be the idea that the plane was in a phugoid: plunging quickly, then rising again, then plunging again. But as I wrote in a previous post, simulator runs by Mike Exner suggest that these extreme rates of descent are characteristic of the later stages of an unpiloted post-flameout plunge, when phugoid effects are overwhelmed. Thus, if the ATSB is correct in interpreting the final BFO value as a very steep plunge–as Gordon assures us they must–then the plane should be well within 15 nautical miles of the seventh arc.

The chart above (based on the invaluable work of Richard Cole) shows a band of seabed, marked in red, defined by an outer border that is 15 nm beyond the 7th arc and an inner border that is 15 within the 7th arc. As you can see, this band has almost entirely been searched out to the 99% confidence level as defined in Figure 2 of my previous post (located at the intersection of the 7th arc and 94.85 degrees east). All that remains is a rectangle approximately 17 km wide and 150 km long, for a total area of 2,550 sq km.

According to Figure 3 in that same post, the DST calculates that the probability that the plane crossed the seventh arc northeastward of 96.75 degrees east longitude is effectively zero. To search to this longitude would require covering another 3,700 or so sq km. Thus, to cover all the seabed that MH370 could plausibly have reached, if the ATSB’s BTO and BFO analysis is correct, would require another 6,250 sq km of seabed scanning, which is more or less what the ATSB has been planning to search anyway. Unfortunately, the search at present is not taking place in either of these remaining areas.

As I see it, there are four possibilities at this juncture:

  1. Both the BFO and the BTO analysis are correct, and the plane is lying somewhere in the remaining 6,250 sq km described above.
  2. The BTO analysis is correct, but the BFO analysis is wrong. In this case, the plane was not necessarily descending with great rapidity, and instead might have been held in a glide, and is most likely in “Area 1” shown above.
  3. The BTO analysis is incorrect, and the BFO analysis is correct. The plane was indeed descending very rapidly during the last ping, but the plane was further to the northeast somewhere in “Area 2.”
  4. Both BTO and BFO analysis are incorrect. The plane could be just about anywhere.

I happen to believe that the DSTG knows what it is doing, and that 2 through 4 are not the case. On the other hand, the unsearched areas remaining are at the far fringes of likelihood, and so don’t feel that #1 is a high-probability option, either. No doubt some will argue that the plane might have been overlooked within the area already searched, despite assurances from officials that if it was there they would have seen it.

Frankly, we’re running out of compelling options.