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EXPLANATORY JOURNALISM: The TerryReport
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News, commentary, opinion on politics, government, books, social trends, American life, travel, cycling, books, other stuff
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NORTH/SOUTH FLIGHT MAPS ARE PROBABLY WRONG AND LITTLE MORE THAN EDUCATED GUESSES, SENDING THE SEARCH OFF COURSE AGAIN
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News media around the world are suggesting that the missing Malaysian Air jet could have followed a flight path north or south from its last known position. This should be put under the heading of “informed speculation”, which is only one or two notches better than mere speculation.
As far as I can tell, the supposition which underlines the two flight paths is derived from the idea that one Inmarsat satellite was receiving small bursts of information from the aircraft. If the plane had gone beyond the footprint of that given satellite, Inmarsat III, then the bursts would have been picked up by a different satellite and, therefore, we would know the direction in which the plane was flying.
Here is what is wrong with the underlying assumption behind those two flight paths: It is based on the fact that the bursts were still coming, indicating that the aircraft was in flight without any known direction or speed. What if it were essentially flying in circles? What if it flew west for a time, then turned back east and then turned back west? The same satellite would have been receiving the bursts, but it wouldn’t have gone anywhere, east or west, in the time period.
Inmarsat says they can do calculations to show about how far from the satellite the aircraft was at the time a given burst was sent, but those calculations, obviously, are not nearly good enough to provide anything close to accurate position information.
What one cannot rule out cannot be discounted in a strange, unmediated investigation like this one. So, by my understanding of satellite technology and what little I know about how Inmarsat helped government officials in Malaysia come up with the north/south possibilities, those maps are probably worse than useless because they are creating a new false assumption about where the aircraft might be. Bad information is worse than none. The vector lines from the last position should go outward from the last known position to the entire area the aircraft could have reached without crossing into a new satellite footprint. That means the search area is millions of square miles wide, making any intentional discovery of wreckage almost an impossibility.
This entire search process is clearly in need of someone to take it over and direct it in a more calm, intelligent way. One safety expert said Sunday that we might find that some wreckage of the aircraft in the months or years to come when it washes up on a beach somewhere. Right now, that looks like the likeliest possibility.
Doug Terry, 3.17.14
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This is an example of how the north/south paths are being reported by media around the world. This clip is from the Washington Post:
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Based on an analysis of satellite contact the plane made in its final hours, investigators think it could have ended up anywhere along one of two massive arc, extending north into Asia and south into the Indian Ocean. The northern and southern corridors are being treated with “equal importance”, Hishammuddin said.
The northern corridor crosses 11 countries from Thailand to Kazakhstan. The southern is far more remote and stretches through areas that are uncovered by radar. To help with the northern area, Malaysia’s government has requested help from nearly a dozen Asian countries, including Burma, Pakistan, Bangladesh, Uzbekistan and Turkmenistan and Australia. The Malaysian Foreign Ministry on Sunday held a briefing for 22 countries and asked them to share satellite and radar data that may give clues into the plane’s whereabouts.
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In addition to the north/south probable flaw, it is startling that the Malaysian government would only now be asking nearby countries to check their radar signatures. When a plane is missing, it is missing. Asking for a routine check of any unknown aircraft passing through their radar systems, it would seem, could have been done within the first 24 to 48 hours (at the most).
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The Inmarsat III satellite system (see comment below)
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Hypoxia, oxygen deprivation, should not be ruled out as a possible cause for flight 370 flying for a long time after it changed directions. More on this coming up soon on The TerryReport.
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CNN obtained this comment from an American officials, unnamed. It seems that they are somewhat confused about how the Inmarsat satellite could locate the aircraft.
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"We're trying to get up to speed on what that means and how to interpret it," one U.S. official told reporters. "It's sort of a new technology for us."
"We have never had to use satellite handshaking as the best possible source of information," the official said.
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This map shows the satellite that would have picked up the signals from the still flying Malaysian Air flight 370. The wide blue oval shape represents the satellite that would have been picking up signals from 370 near the time of its last contact with ground control. The large green oval shape is the footprint of the next, westward satellite, which did not pick up any signals from the flight.
The assumption seems to be that since it did not cross into the footprint of another satellite by going straight west or east, it must have been flying north or south. This assumption, at first blush, is reasonable, but the movements of the aircraft up to that point do not support reason. The movements were erratic after it left Malaysian airspace both in direction and altitude. There is no reason to assume those movements became less erratic later, unless one knows there was a specific target, somewhere the aircraft was intentionally being flown. From what we know now, that was not the case, of course. The actual probable search area extends west from the last point of known contact to the large green oval (satellite footprint) that extends westward well beyond the southern boundary of India. In other words, it is an area almost too large for any search to have a good chance of finding anything.
ADDED COMMENTS (4:50 PM, eastern time, 3.17.14):
CNN reports that the Inmarsat satellite has to “know” the angle at which the signals are being sent and returned to the aircraft. This is contrary to my long understanding of how satellites operate, unless they are using a spot beam (focused on a smaller area) technology. Generally, satellites operate as simple relay points, a signal comes in and it is sent back out to a wide area, covering the entire footprint of the service area for that particular satellite. This is often referred to a a bent pipe system in which the satellite has no role in processing signals, they simply hit the bent pipe and are sent on their way.
There is a reason that satellites generally operate with this kind of simple transponder relationship. The more onboard processing there is on a satellite, the bigger and heavier it gets, which makes launching it more difficult and expensive and maintaining it in good operating condition more risky. The idea is to put as much power as possible into handling as many signals as possible, thus reducing the onboard processing of signals. Some satellites, particularly newer ones, do onboard processing, such as sending signals from one satellite to the next to allow them to be downlinked to different areas of the world, but, in the main, the up and down pipe system is what is used, sort of like an image bouncing off a mirror. Spotbeams, which are used on the Inmarsat fleet of satellites, redirect the signal to a specific, smaller area to increase the amount of power going to a specific application, thus allowing for higher data rates and/or smaller terminals.
The Inmarsat website, citing information about its worldwide satellite telephone system, says that the satellites use GPS information in order to assign the proper spot beam to the sat phone. The system on flight 370, however, was said not to contain GPS information. (If it had that information, this entire debate would be moot.) There is a serious conflict here. The maps showing sweeping lines up and down from the last known position of flight 370 are said to reflect information obtained from the satellite about the angle at which the aircraft was in relation to the satellite. If a spot beam were being used, why would the angle encompass such a large area? How would the satellite assign the spot beam without the GPS information, which Inmarsat’s website says is necessary for that function? This doesn’t add up and The TerryReport stands by the above conclusion that the two sweeping arcs depicted and distributed around the world are most likely the product of informed guessing and probably capable of doing more harm than good.
The search area, at minimum, should extend forward from those arcs by several hundred miles, at least, and the chances of finding wreckage becomes more a matter of blind luck, even if the maximum number of search planes were deployed. The area to be searched, in short, appears to be close to the size of the entire lower 48 states. If this is the correct conclusion, it doesn’t mean searching should be called off, but that it might need to be doubled and doubled again in terms of the number of planes being used and, further, that we probably will need to wait for some new information, some breakthrough, to allow a more focused search.
I will post additional information or clarification here as it becomes available.
Doug Terry, 3.17.14
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to go to recent posts, nearly 300 pages of news and comments filed during the first nine months of 2013 and during the critical election year of 2012.
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to go back to prior years (500+ pages) of The TerryReport
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