The Lost Airliner

Perhaps the single most comprehensive summary of developments — or lack thereof — in the MH370 mystery is by Bruce Drum of World Airline News. It lays out the state of knowledge about what happen to missing Malaysian Airlines jet and where the search may go from here. Australia has drilled a dry hole in it’s last best guess area which it is scouring with the autonomous underwater vehicle called the Bluefin-21. “The Bluefin-21 will be redeployed in this new area. The exact new area is still being determined.”

The new phase “will be a major undertaking … The equipment used for the search will likely include a towed sonar, an Autonomous Underwater Vehicle with mounted sonar, and optical imaging equipment. We expect the search to begin in several months and take up to 12 months to complete.” The very fact they didn’t find anything in the first search underscores how uncertain the knowledge is. Plan A failed, it’s now on to Plan B.

Why are they looking in the the new area? It’s one of the other possibilities suggested by the satellite signalling system which is all they’ve got to go on after the last reliable radar data.

Following the loss of primary radar, the only available information was from satellite signalling messages, also referred to as ‘handshakes’, between the ground station, the satellite and the aircraft’s satellite communication system. For each transmission to the aircraft, the ground station recorded the burst timing offset (BTO) and the burst frequency offset (BFO). …

The meaning of the BTO is straightforward. It defines the “arcs” along which the plane might be found. These rings describe the famous ‘arcs’ that were used to determine the “northern” and “southern” routes which formed the set of possible locations for MH370. “There were 7 handshakes between the ground station and the aircraft after the loss of primary radar data. The location rings calculated from the recorded BTO values are shown in figure 4. … The 00:19 signalling message (7th arc) was a logon request from the aircraft. This is consistent with the satellite communication equipment on the aircraft powering up following a power interruption. The interruption in electrical supply may have been caused by fuel exhaustion.”

The BTO is a measure of the time taken for a transmission round trip (ground station to satellite to aircraft and back) and allows a calculation of the distance between the satellite and the aircraft. Based on this measure, a possible location ring can be mapped on the surface of the earth (Figure 3). An analysis of SATCOM system parameters showed that the accuracy of the rings was ± 10 km. This analysis was validated using recorded BTO values from the initial stage of the flight when the aircraft’s position was known.

How far did it go?

Why aren’t they looking in the north? Much of the answer can be found in the Australian Transportation Safety Bureau (ATSB) report, which describes the BFO or burst frequency offset (BFO) in much more detail than the news articles. The BFO is the source of Doppler data, “the recorded value of the difference between the received signal frequency and the nominal frequency at the Ground earth station (GES).”

Once the known error associated with the BFO is removed, the remainder is the Doppler Effect associated with the relative motion of the aircraft to the satellite (ΔFup). For a given relative motion, there are many combinations of aircraft speed and heading that will produce the correct frequency change (BFO). There is however a limited range of speeds at which an aircraft can operate and therefore the number of feasible speed/direction solutions is limited.

Those limitations constrain positions on the arcs. The BFO generates a series of best-fit-to data lines which intersect with the BTO arcs. These intersections arewhat defines the Southern area.

Intersection

The searchers are working on the theory that the 00:19 signal — the last arc — occurred near to the aircraft’s fuel exhaustion, and therefore the wreckage is near to it. “The intensified search will begin in August 2014 and is expected to take up to 12 months, depending on weather conditions. The successful tenderer will use the data from a bathymetric survey (already underway) to navigate the search zone, which has water depth between 1000 and 6000 meters.”

The ATSB investigators very carefully avoid making any conclusions about what happened on MH370, except to say that the airplane appeared to be flying in a manner consistent with autopilot for a long time. Were there dead men at the controls? Was everyone on the airplane dead for hours? The Malaysian police, for whatever it is worth, have named “captain Zaharie Ahmad Shah as the chief suspect, if human intervention is to blame.”

Police have not out alternative causes, such as mechanical failure or terrorism – they simply suggest that if foul play is involved, Captain Zaharie is the likely perpetrator. He is known to have installed a flight simulator in his home, and police investigators now say he had programmed flights out into the Indian Ocean that involved landing on a small island airstrip. The data had been deleted from the simulator but police were able to recover it.

That’s like saying that if Inspector Clay was murdered then somebody’s responsible. How much meaning there is in the Malaysian police report is questionable. Something happened on MH370 but we don’t know what it was. Nor perhaps can we ever know. Given the size of the search area, probabilities and assumptions have to worked into the position modeling. Abstraction makes it tractable but it introduces a necessary simplification or “white lie” into the analysis. We cannot know exactly how far the simplification lies have taken us from the truth, and all we can do is make the best guesses and hope they are close enough.

Plan A failed. Maybe Plan B must fail as well. The sea is a big place. Maybe the writers of Plan 9 have the right lines for the MH370 mystery.

Col. Edwards: This is the most fantastic story I’ve ever heard.
Jeff: And every word of it’s true, too.
Col. Edwards: That’s the fantastic part of it.

Recent items of interest by Belmont readers based on Amazon click-throughs.
Capitalism: The Unknown Ideal
Quantum: Einstein, Bohr, and the Great Debate about the Nature of Reality
Quantum Enigma: Physics Encounters Consciousness
The Camp of the Saints
With the Old Breed: At Peleliu and Okinawa
Cretaceous Dawn
Let Me Be Clear: Barack Obama’s War on Millennials, and One Woman’s Case for Hope

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Rebranding Christianity for $3.99, or why the truth shall make you free
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Storming the Castle at Amazon Kindle for $3.99, why government should get small
No Way In at Amazon Kindle $8.95, print $9.99. Fiction. A flight into peril, flashbacks to underground action.
Storm Over the South China Sea $0.99, how China is restarting history in the Pacific
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