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New Information May Narrow Down Malaysian Jet's Path 227

Posted by timothy
from the not-that-hard-to-lose-a-plane dept.
mdsolar (1045926) writes with this excerpt from Slate on the still-missing Malaysian Airline flight "In a case that is swirling with uncertainties, a few pieces of evidence have stood apart for seeming reliability. Among them was the revelation last Saturday by Malaysia Prime Minister Najib Razak that his country's investigators, in collaboration with U.S. authorities, had analyzed an electronic ping that MH370 had broadcast to the Inmarsat satellite at 8:11 a.m. on the morning of the disappearance. Based on this data, the investigators had determined that at that moment MH370 must have been somewhere along one of two broad arcs: one which passed through Central Asia, and the other of which covered a swath of largely empty Indian Ocean, far to the south. The revelation left a burning question unresolved: what about the six earlier pings, which had been exchanged between the aircraft and the satellite about once per hour? Could any position data be deduced from them? Today, Inmarsat revealed some crucial information. 'The ping timings got longer,' Inmarsat spokesman Chris McLaughlin stated via email. That is to say, at each stage of its journey, the aircraft got progressively farther away from the geostationary satellite's position, located over a spot on the equator south of Pakistan, and never changed its heading in a direction that took it closer—at least for very long."
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New Information May Narrow Down Malaysian Jet's Path

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  • by careysub (976506) on Saturday March 22, 2014 @01:02AM (#46549223)

    Here is a very detailed account of the trajectory data now available from Reuters [reuters.com]. Maybe someone on this board knows air routes in South East Asia and can provide analysis or pointers to useful maps?

  • Re: Sigh. (Score:3, Informative)

    by Anonymous Coward on Saturday March 22, 2014 @01:24AM (#46549299)

    Yes they do. (Or very nearly -- the index of refraction of air to RF pulses is very nearly 1)

  • by Solandri (704621) on Saturday March 22, 2014 @01:45AM (#46549353)
    The planes have ELTs [wikipedia.org] designed to activate upon impact and relay their GPS location to satellites (Steve Fossett's plane would've been found within hours if he had had one of these). AFAIK those aren't waterproof though. The escape slides (which double as rafts) should have EPIRBs aboard, which are waterproof. However if the rafts aren't deployed then obviously they'll sink and the EPIRBs won't do a whole lot of good.

    The black boxes give off a 35 KHz acoustic ping every second. The batteries should be good for 30-35 days. Unfortunately, 35 KHz sound attenuates rapidly in seawater, so you only likely to hear it up to about 2 km away. If the plane is sitting in more than 2 km of water, the only way you'll hear the pings is if you're very lucky on the surface, or from deep water submersibles.

    I think the assumption was that you would have enough radar data to narrow down the search area to a few hundred or few thousand square km at most. AF447 was probably considered a fluke. Now that a second plane has "disappeared" in a similar manner, expect to see the required locating equipment changed. One obvious change would be to equip all commercial aircraft with an EPIRB designed to float free if the plane sinks. It won't give you the plane's exact location due to wind and currents, but it'll prevent these "we have no idea where the plane is" situations. Unlike the previous locating idea posted on /. which cost $100k per plane, an EPIRB only costs a few hundred dollars.
  • by hankwang (413283) on Saturday March 22, 2014 @01:48AM (#46549365) Homepage

    "they already have such beacons which ping for 30 days after activation. Why are they not picking any of that? "

    http://en.wikipedia.org/wiki/U... [wikipedia.org]

    Typical detection range is 5 km. Say the plane can be in a 2000x2000 sq km area. Then you have to search in a search path that is 200x2000=400,000 km long. That's 10x around the earth and will take a while.

    And the ocean is 4 km deep once you're well away from land; because of the vertical distance you have less horizontal range.

  • Re: Sigh. (Score:5, Informative)

    by ClickOnThis (137803) on Saturday March 22, 2014 @02:02AM (#46549423) Journal

    Radio transmissions do not occur at the speed of light.

    Radio waves and light waves are both electromagnetic radiation, just at different wavelengths. In vacuum, electromagnetic radiation travels at speed c for all wavelengths. In non-vacuum media, there may be some dispersive effects that cause the speed to change with wavelength, but those effects are very small in air.

    In short, radio waves travel at the speed of light because, in a very real sense, radio waves are light, just not light at a wavelength our eyes can see.

  • by Anonymous Coward on Saturday March 22, 2014 @02:11AM (#46549457)

    Skyvector [skyvector.com] is your friend.

  • by Anonymous Coward on Saturday March 22, 2014 @02:17AM (#46549475)

    http://www.wired.com/autopia/2014/03/mh370-electrical-fire/

    I believe something like that happened. Occam's razor and so on...

    The fact that the pilot had built his own simulator also has a mundane reason that somebody on pprune had tracked down: He assisted with giving a real pilot's feedback to a third-party developer of aircraft for flight simulators (X-Plane IIRC).

  • Re:Sigh. (Score:4, Informative)

    by AK Marc (707885) on Saturday March 22, 2014 @02:36AM (#46549533)
    They use a shared TDMA return to best allocate bandwidth. The timing is measured in microseconds (and no, not millions of them). The time to the GEO satellite can be learned and used to deduce distance, thus an arc. It's pretty accurate.
  • by KeensMustard (655606) on Saturday March 22, 2014 @04:11AM (#46549775)

    Small boats regularly depart illegally from Indonesian beaches,

    It 's not illegal to leave Indonesia by boat.

    heading for other countries and when told about it, the Indonesians show zero interest in arresting and charging the crews and passengers or even taking them back.

    People travel by boat between countries all the time. In my country (also Australia) 30,541 boats arrived here in the 2011/2012 FY. [portsaustralia.com.au]That's just the commercial vessels, not including pleasure craft, navy visits etc.

    Of course the Indonesians aren't interested in stopping something that is not illegal or immoral, or damaging to their economy, or ours.

  • by Stellian (673475) on Saturday March 22, 2014 @04:20AM (#46549797)

    Here's a map of the pings:
    http://theaviationist.com/wp-c... [theaviationist.com]

  • Map not factual (Score:5, Informative)

    by craighansen (744648) on Saturday March 22, 2014 @10:26AM (#46550989)

    Unfortunately, this map has non-factual locations for the circles other than 8:11. The angle information for the earlier pings has not been released, but artwork was drawn up that estimated these earlier pings from the reported estimated tracks attributed to the NTSB. This artwork, drawn by Scott Henderson, was likely the source for the map on theaviationist.com's site. See http://willyloman.wordpress.co... [wordpress.com] for details.

    Inmarsat has been coy about the exact value of the ping angles. They issued a press release that said that the information had been given to the Malaysian government, and that anyone who wanted details should contact Malaysia. See http://www.inmarsat.com/news/i... [inmarsat.com] IMHO, they have been doing this because the earlier ping data may make clearer that the aircraft track takes it over Malaysia, where the lack of detection may be a source of official embarrassment.

    The earlier ping data may also indicate whether MH370 overflew Indonesia, or whether it flew west to avoid Indonesia, and that has an effect on the plane's remaining range and the estimate of the flight's bearing when it presumably turned southward toward the 90E/45S region where the SAR operations have been focused lately. It would appear that this data was factored into the NTSB track estimates, but the lack of an official release of the angle data has hampered the armchair/amateur speculation about the location. IMHO, if MH370 avoided overflying Indonesia, it may have been a deliberate attempt to lay a false track in a west or northwest direction.

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