Category: MH370

A week after MH370 went missing, the Malaysian government dropped a shocker: Inmarsat, the satellite communications provider, had recorded signals from the plane that allowed them to calculate the plane’s distance from the satellite about once an hour for nearly six hours.

At first, the Malaysians only released a rough sketch of the final arc: two matching fragments of a circle, 3000 miles in radius, that stretched from Kazakhstan in the north to the remote Indian Ocean in the south. This in itself was a major step forward, in that it drastically reduced the numer of possible places the plane could have gone. But even more enticingly it suggested that if we had the numerical values for all the pings, and could figure out what speed the plane was flying at, we would be able to identify the route that the plane was taken and thus its precise final destination.

The scientists at Inmarsat recognized this immediately, and as Chris Ashton et al relate in their paper in the Journal of Navigation, they quickly plugged in the most logical speed value — typical airliner cruise speed, around Mach 0.83 — and concluded that the plane flew either to the middle of Kazakhstan or almost directly south into the Indian Ocean. (See image above.) As a result, the Malaysian government submitted a request to the Kazakh government asking that it be allowed to set up a search operation in the country, and planes were dispatched to search the ocean surface near the southern potential end point. Hopes were high. After satellites spotted what appeared to be floating material in the southern ocean, Australian Prime Minister Tony Abbott told his country’s parliament that it was a “potentially important development.’’

Of course the idea that the plane flew straight and fast, as airliners typically do, was just an assumption. Theoretically, it could have flown from ping ring to ping ring at any number of speeds along any number of routes, including straight, curvy, and zig-zag. Most of these alternatives would have resulted in the plane winding up at a lower latitude. And indeed, within a few days the authorities abandoned the southernmost search area and started scouring a section of the ocean much further north. The decision to shift the search zone appears to have been heavily influenced by a second set of data also derived from the handshakes exchanged between the plane and the satellite: the so-called BFO (“burst frequency offset”) data. After much head-scratching, Inmarsat believed that they had come up with an algorithm that allowed them to understand the physical implications of this data, and it told them that a) the plane had definitely gone south, not north, and b) the plane had not been flying straight and fast, as initially supposed, but instead taken a slower and/or meandering course and wound up about a thousand miles from the initial search area.

Frustratingly, for those of us who were watching from the sidelines and eager to understand what was going on, neither Inmarsat nor the Malaysians were willing to either release their numerical data nor to explain their BFO algorithm. We just had to take their word for it. Which was enormously frustrating, since it seemed tantalizingly plausible that if we had the data and understood the physical processes that generated it, we would be able to mathematically solve for the location of the plane. Et voila: mystery solved.

Finally, after much pressure from the public, the Malaysians did finally release most of the Inmarsat data in May; the following month, the Australian Transport Safety Bureau (ATSB) released a report which explained how the then-current search area had been arrived at and explained in some detail how the BFO algorithm worked.

Many independent experts, including members of the Independent Group, leapt at the chance to finally get under the hood of the BFO algorithm and see if they could reach their own conclusions about where the plane went. In time, however, their optimism faded. In turns out that the BFO data offers only a very imprecise gauge of a plane’s location or direction of travel. To test the algorithm, for instance, scientists working for the search effort compared BFO data received from a known flight with the plane’s actual path. They found that, of the thousands of possible paths that matched the BFO data, even the one that most closely matched the actual flight was hundreds of miles off in places.

We seemed to be almost back to where we started: we had a set of ping rings that showed us seven quite accurate (within 10 km, the ATSB estimates) arcs along which the plane must have been at seven moments in time, but with only vague intimations of where along those arcs the plane actually was.

Gradually, however, without much fanfare, it has become clear that other, non-BFO techniques can provide insight into how MH370 was traveling after it disappeared from radar, and these in turn offer a strong suggestion about where the plane went.

Continue reading How We Can Tell How Fast MH370 Was Flying

One of the many baffling aspects of the MH370 disappearance is the absence of radar data after the plane left Malaysian primary coverage at 18:22 UTC. If, as is generally presumed, the plane took a sharp left turn shortly afterward and flew into the southern ocean, it should have remained visible to Indonesian radar for more than an hour. Yet Indonesian military officials insist that nothing appeared on their radar screens.

This is an issue that has gotten less attention than it deserves, and for understandable reasons. Indonesia is a developing country, and a sprawling one at that. With a land area the size of Western Europe, it spans the same east-to-west distance as the continental United States. So one might reasonably assume that the country lacks the ability to comprehensively monitor its airspace. Why shouldn’t MH370 have passed through without a trace?

In fact, though, Indonesia has quite a capable air defense radar system, and one which it utilizes quite aggressively. In the last month alone, its air force has intercepted three civilian planes which wandered into the national airspace without first getting the proper permission.

The westernmost part of the country is covered by the Indonesian Air Force’s Radar Unit 231 at Lhokseumawe in Aceh, Northern Sumatera. The unit is equipped with a Thomson-CSF TRS-2215 radar, the type pictured above. The system, Indonesian military officials say, is capable of detecting aircraft up to 240 nautical miles away.

It demonstrated its capability last year, when the unit detected a Dornier 328 twin turboprop entering Indonesian airspace from the west. The plane was ordered to land at Sultan Iskandar Muda airport in Banda Aceh. It turned out to be a US Air Force Special Operations plane carrying five crewmembers; the pilot claimed he had been running low on fuel and didn’t realize that his paperwork to enter the country had expired. After being impounded for a few days the plane and its crew were allowed to leave.

Based on its specs alone, Radar Unit 231 (so much easier to spell than Lhokseumawe!) should easily have been able to detect MH370. The radar track released by the Australian Transport Safety Board (ATSB) in June shows that the plane came within 60 nautical miles of the installation before it disappeared from Malaysian and/or Thai military radar. Afterwards, according to the consensus view, the plane’s track should have stayed within the radar’s viewing range as it headed west, made a turn to the south, and proceeded into the southern Indian Ocean. (See map after the jump)

So how could the Indonesians have seen nothing?

Continue reading MH370 and the Mystery of Indonesian Radar

 

Newly emerged details concerning Malaysia Airlines flight 370’s electrical system indicate that whoever took over the plane was technically sophisticated, possessing greater knowledge of Boeing 777 avionics than most commercial line pilots. They also suggest that the plane’s captain, Zaharie Ahmad Shah, was not responsible for taking the plane.

The new information comes via Michael Exner, a satellite industry veteran who has been one of the most prominent independent experts investigating the airliner’s disappearance. Several days ago Exner gained access to a major US airline’s professional-grade flight simulator facility, where he was able to run flight profiles accompanied by two veteran 777 pilots. “This is a state-of-the-art 777 simulator, level D, part of one of the most modern training facilities on earth,” Exner says.

A little background. As is well known, approximately forty minutes after its departure from Kuala Lumpur for Beijing, someone turned off all communications between MH370 and the outside world. Around the same time the plane turned sharply to the left and headed back over the Malayan Peninsula. Among the systems that were shut off were satellite communications; the transponder; and two automatic reporting systems, ACARS and ADS-B. The plane went dark just as it entered the space between two air-traffic control zones and was temporarily unmonitored, a sign that whoever planned the diversion wished to avoid detection and was well versed in international air traffic control procedures.

For approximately the next hour, MH370’s progress was visible only to military radar. The plane flew straight and fast between established navigational points, indicating that the aircraft had not suffered mechanical accident. At 18.22 UTC the plane was heading west out into the Indian Ocean when it passed out of range of military radar. At that point, the plane became effectively invisible. Shrouded in night, with approximately six hours’ fuel aboard, the plane could have reached any point within a 3000-mile radius and no one on the ground would have been any wiser. But it did not stay dark. Less than a minute later, MH370’s satellite communications system was switched back on.

Over the span of several minutes, between 18.25 and 18.28, the Satellite Data Unit (SDU) transmitted a flurry of brief electronic messages with Inmarsat satellite 3F-1, which occupies a geosynchronous orbit above the Indian Ocean. In a report issued this June, the Australian Transport Safety Board stated that the signals were “generated as part of a Log-on sequence after the terminal has likely been power cycled.”

Until now, it has not been publicly known how such a power-cycling could have taken place.

Continue reading MH370 Evidence Points to Sophisticated Hijackers

When Australia called off the surface search for Malaysia Airlines Flight 370 on April 28, Prime Minister Tony Abbot explained that “It is highly unlikely at this stage that we will find any aircraft debris on the ocean surface. By this stage, 52 days into the search, most material would have become waterlogged and sunk.”

But would the debris really have sunk? Modern aircraft are made of metal, composites, and plastic, materials that do not get waterlogged. If, as the Australian Transport Safety Board (ATSB) believes is most likely, MH370 ran out of fuel and then crashed, it would have been moving at hundreds of miles per hour when it hit the sea. Much of the resulting debris would have settled down through the water column, but innumerable pieces would have remained afloat. After Air France Flight 447 went down in the middle of the Atlantic in 2009, searchers found some 3,000 pieces of debris scattered across the surface.

With the passage of time, the absence of MH370 debris becomes increasingly puzzling. Recently Emirates Airlines CEO Tim Clarke expressed frustration over the ATSB analysis of the plane’s fate, saying: ”Our experience tells us that in water incidents, where the aircraft has gone down, there is always something.” This is true. As far as I know, there have been no cases where a commercial airliner has crashed into the sea and no parts were recovered, even if the crash occured in an unknown location far out in the middle of the ocean, as MH370’s presumably did.

Consider the fate of the Boeing 377 Stratocruiser “Clipper Romance of the Skies,” which disappeared on the first leg of a planned round-the-world flight somewhere between San Francisco and Hawaii in 1957. An aircraft carrier was dispatched and found floating debris six days later, halfway between its origin and destination and 90 miles from its planned track, some 1,000 miles from the nearest land.

The area where MH370 is now believed most likely to have gone down is a bit further out to sea, some 1,500 miles southwest of Perth. But far more assets were been deployed in the search, including satellite, ships, and land-based aircraft. Indeed, the area was one of the first to be searched for surface wreckage back in March. 

Still, it’s easy to imagine that even pieces of debris might have been overlooked in the vastness of the sea, especially given the uncertainty surrounding the plane’s crash site. That’s why many have long thought that the first hard proof of the plane’s fate might well take the form of flotsam washing up on a beach somewhere.

 

Continue reading MH370: Where is the Debris?

If you were leading a high-profile international aircraft investigation, in command of the world’s most qualified technical experts and in possession of all the relevant data, would you bother listening to a rag-tag band of internet commenters, few of whom actually work in the space or aviation industry, and none of whom have access to all the data?

Most likely, you’d say: certainly not! But as time goes by, and the puzzle remains curiously impenetrable, you might find it worthwhile to pay a listen to what the amateurs were saying. You might even abandon some of your own conclusions and adopt theirs instead.

This appears to be the case in the search for Malaysia Airlines Flight 370, which disappeared en route from Kuala Lumpur to Beijing back in March. From the beginning, the authorities running the investigation — first, Malaysia’s Ministry of Transport, and later the Australian Transportation Safety Board (ATSB) — held their cards close to the chest, releasing very little information about the missing plane and maintaining a posture of absolute conviction.  The investigators’ self-confidence reached its apex in April, when their methodology led them to an area of ocean where underwater accoustic signals seemed to be coming from pingers attached to the plane’s black boxes. Officials assured the press that the plane would be found in “days, if not hours.” But then it wasn’t. A scan of the seabed found nothing; the pingers were a red herring (perhaps literally!). Back to square one.

Meanwhile, on the internet, a group of amateur enthusiasts had come together from all around the world to trade ideas and information about the missing flight. The group, which came to call itself the Independent Group (IG), emerged from various online comment threads and eventually grew to about a dozen individuals. This was a truly spontaneous, self-assembling crowd: there was no vetting of credentials, no heirarchy of any kind. (Full disclosure: I count myself among this group.) Basically, if you seemed to know what you were talking about and could comport yourself in a collegial fashion, you were accepted into the crowd.

While the mainstream press was reporting the ATSB’s pronouncements as received wisdom, the IG was raising red flags. IG members were among the most vocal critics of the ATSB’s contention that the accoustic pings probably came from black-box pingers. And later, after a public outcry led Inmarsat to release a trove of data received from the aircraft, and the ATSB issued a report explaining how it had come to identify its current search ear, the IG dove into the new information with abandon, quickly identifying holes in the data and weaknesses in the official approach. In a pair of papers, the group recommended its own search area, hundreds of miles to the southwest of the ATSB’s officially designated  zone.

Today, the ATSB has released an update to its earlier report, explaining why it has decided to reassess its conclusions and move its search zone to a new area — one that overlaps, as it turns out, with the IG’s recommended area. (In the graphic above, the white bracket shows the ATSB area; I’ve added a yellow dot to show the IG area.) Needless to say, this has caused elation within the ranks of the IG, who see the move as vindication of their methods, and indeed validation of their combined efforts over the last few months.

A few observations on the new report:

Continue reading In Search for Missing Airliner, Peanut Gallery Shows the Way

It’s been more than six months since MH370 vanished, and in some ways we know no more now than we did in late March: no new clues have emerged, no more data has been discovered.  In a sense, though, we have come a very long way. For one thing, we now understand how many of the “breaking news” developments that occurred in the early days were actually untrue. (There were no wild altitude swings, no “fighter plane-like” maneuvering, and probably no cell-tower connection with the first officer’s phone.) What’s more, thanks no doubt to a drumbeat of public pressure, the authorities have released a tremendous amount of data and provided useful explanations of how that data is being interpreted. And finally, a spontaneous collaboration between technical experts and enthusiasts around the world has provided a trove of insight into avionics, aerodynamics, satellite communications, and a whole host of other topics that collectively shed light on what might and what might not have taken place on the night of March 7/8, 2014.

While a great deal of information has become available, it has not always been easy to find; much of it, for instance, has been exchanged via email chains and Dropbox accounts. For my part, I often find myself rummaging through emails and folders looking for information that I’m pretty sure I’ve seen, but can’t remember where. So what I’d like to do with this post is try to aggregate some of the most basic facts — a set of canonical values, if you will, of the basic data on MH370. Necessarily, some of this data comes with implicit assumptions attached, so as far as possible I’ll try to make these assumptions explicit.

Okay, on to the data. What we know now:

The bedrock data. In the wake of MH370’s data, there were numerous news reports concerning information leaked by anonymous sources from within the investigation and elsewhere that have subsequently been either disproven or inadequately verified. For the purposes of the present discussion, the following are considered the bedrock sources of information upon which our understanding of the incident can be built — the “Holy Trinity” of MH370 data:

1. Up to 17:21: radio communications, ACARS, transponder, ADS-B
2. 17:22-18:22: military radar track. This information is of uncertain provenance but has been endorsed by the governments of both Malaysia and Australia. Furthermore, it plausibly connects the prior and following data sets.
3. 18:25-0:19: Inmarsat data, especially BFO and BTO values. There is some discussion as to how this data is best interpreted, but the numbers themselves are assumed to have been received and recorded by Inmarsat from MH370 via their 3F-1 satellite. The “ping rings” in particular are derived through relatively simple mathematics and should be regarded as established fact unless someone comes up with a specific mechanism by which some other result could be obtained.

Timeline. Courtesy of Richard Godfrey and Don Thompson, here is a basic timeline of MH370’s disappearance (all times UTC):

• 16:41:43 MH370 departs runway at KUL runway 32R
• 17:01:14 MH370 flight crew report top of climb at 35,000 feeet
• 17:07:48.907 Last acknowledged DATA-2 ACARS message sent from plane
• 17:19:29 Last radio voice transmission
• 17:21:04 Plane passes over IGARI waypoint
• 17:21:13 MH370 disappears from air traffic control (secondary) radar screens
• 18:22 Last primary radar fix
• 18:25:27 Inmarsat log-on request initiated by aircraft
• 0:19 Final transmission from aircraft to satellite

A more complete table of values, including the location of the plane at each point in time, can be found here, courtesy of the inimitable Paul Sladen. And Don Thompson has created an impressively detailed breakdown of the sequence of events, with a special focus on radio communications between the aircraft, ground, and satellite, here.

More stuff after the jump…

Continue reading What We Know Now About MH370

 

In what must as the most significant act of rapprochement in the history of underwater aircraft-accident investigation, it was learned today that the Fugro Equator, a bathymetry vessel contracted to map the seabed as part of the Australian government’s efforts to locate missing Malaysia Airlines Flight 370, has begun exploring the area that the Independent Group has identified as the jet’s most likely resting place. The chart above, supplied by Geoff Hyman [update 10/3/14: I’ve replaced it with a newer image from Don Thompson], shows the course of the Equator’s recent progress in red. The center of the Independent Group’s recommended area is marked with a blue cross. For months, the Australian Transport Safety Board has been focussing on an area hundreds of miles to the northeast, on the basis that flight routes that best fit Inmarsat data are most likely to terminate in such an area. The Independent Group has taken a different approach, and focused on routes that are both psychologically plausible and comport better with the way that airliners are actually flown. It is not known if the Equator’s current search zone indicates that the ATSB has come around to the independent expert’s line or reasoning, or is simply being thorough in mapping the entire zone where the plane might have come to rest.

Yesterday the “Independent Group” (IG) of technical experts looking into the disappearance of Malaysia Airlines flight 370 (of which I am a part) released a new report which made the case that the official search area now being scoured by undersea robots is not where the plane most likely crashed. The reason, the group explained, is that the Australian Transport and Safety Board has relied on a statistical model in which hundreds of possible paths were generated, then winnowed down to include only those that fit the timing and frequency data from the seven handshake pings; this resulted in a distribution whose greatest density coincides with the current search area. The Independent Group, in contrast, began by asking what possible routes most closely match the flight speeds and altitudes that a pilot would most likely choose:

The ATSB analysis used two basic analysis techniques referred to as “Data Driven” and “Flight path/mode driven”… While we agree that these statistical methods are reasonable techniques, both tend to overlook or minimize likely human factors in favor of pure mathematical statistics. This ATSB approach appears to have resulted in a conclusion that the most likely average speed was approximately 400 kts (Appendix A). However, 400 kts is not consistent with standard operating procedure (typically 35,000 feet and 470-480 kts), nor is it consistent with the likely speed a pilot would choose in a decompression scenario (10,000 feet and 250-300 kts). A speed of 400 kts may minimize the BTO and BFO errors for a given set of assumptions, but the errors can also be shown to be very small for other speeds. Given all the tolerances and uncertainties, we believe it is important to consider human factors with more weight… B777 pilots consistently tell us that under normal conditions, the preferred cruise attitude would be 35,000 feet and the TAS would be approximately 470-480 kts. We believe this is the most likely case for MH370, and note that the last ADS-B data available indicated that MH370 was at 35,000 feet and 471 kts at that time.

As can be seen in the chart above, the differing approaches result in search areas that are some 500 miles apart. The full report can be found online here.

UPDATE 9/12/14: Richard Godfrey has pointed out that a recent report from the ATSB  shows that the seabed-mapping effort has recently been extended some 200 nautical miles toward the IG search area:

 

 

At a press conference in Canberra today, Australian Deputy Prime Minister Warren Truss state that “further refinement of satellite data” indicated that missing Malaysia Airlines Flight MH370 had turned south earlier than investigators had originally thought. This implied, he said, that the plane had most likely would up further to the south than previously estimated.

The previous assumption was laid out in a report released in June by the Australian Transport Safety Board (ATSB), which included the map shown here. The document described a methodology for determining the search area which suggested that the plane did not make a single turn to the south and then fly on a straight-ahead course into the southern ocean, but rather lingered near western Sumatra for the better part of an hour.

After the report was issued, a loose coalition of experts from around the world called the Independent Group (of which I’m a part) released a statement which questioned the ATSB’s methodology, and in particular pointed out that signal data related to an attempted satellite phone call at 18.40 UTC indicated that the plane was already established on a course to the south. This fact allows the range of possible flight paths to be narrowed considerably.

As fate would have it, Truss’ announcement came just one day after the Independent Group issued a follow-up statement reminding the authorities that its own analysis suggested a search area futher to the south.

“The data is nothing new, but the fact that the Australian government has chosen to issue this statement is very interesting,” says Independent Group member Victor Iannello.

Truss was vague as to where the priority search area had shifted, saying it remained “within the search area” previously laid out in the southern Indian Ocean. This area, however, is more than 1,500 miles long.

It’s been two months since I last posted about MH370, so I think I’m overdue for an update. The big news that’s happened in the meantime is that on June 26th, the Australian Transport Safety Board (ATSB) released a report that laid out in admirable detail what the authorities felt they knew about the circumstance of MH370’s disappearance and how they had come to narrow down its likely location to the current search area. We now have a much clearer understanding of just what Inmarsat’s data reveals about the last four hours of the flight.

In the report, the ATSB explains that sometime after the plane vanished from radar screens at 18:22 GMT, whoever was in control  most likely became incapacitated and the plane flew on autopilot until it ran out of fuel and crashed into the depths of the Indian Ocean some time after 0:19 GMT. Its impact point, according to the ATSB’s calculations, was most likely somewhere in a region 1,000 miles off the coast of Western Australia.

As you’ll notice, that last sentence is extremely vague. The reason is that, as we now understand, the data is incapable of telling where the plane went with any degree of certainty. That is to say, you cannot recreate the airplane’s flight path using Inmarsat data alone. This is kind of a shocker, because for months now, Inmarsat has been telling the public that their mathematical wizardry had allowed them essentially to solve for the plane’s final location. This turns out to be false. For any given flight path, we can now calculate the expected BTO and BFO values; but given a set of BFO and BTO values, we cannot derive a unique flight path.

Take a look at the route chart at the top of this post, which comes from page 31 of the ATSB report. It shows the actual path of a Malaysia Airline jet that flew on the same day at MH370, as well as an “estimated” path generated from the BFO and BTO data recorded from that same airpline. If you’re like me, when you first saw this chart, you assumed that Inmarsat had decoded the BFO and BTO data so thoroughly that they could generate specific flight paths like this one. Give them BFO and BTO data, and they could draw you a line on the map; no wonder they say they know exactly where to spend $56 million scouring the sea bed. But if you read the accompanying text, what it says is: “Using only the starting location and an equivalent number, and approximate time spacing, of BFO and BTO values as the accident flight, predicted paths were created and compared against the actual flight paths.” Reading between the lines, the ATSB was able to generate not just the route illustrated here, but dozens or possibly hundreds, and chose this one as the most promising for MH021.

There’s another disappointing realization embedded in the ATSB report. Continue reading What Could Have Happened to MH370?