Malaysia Airlines Flight 370: Experts Unable To Replicate Inmarsat Analysis 245
McGruber (1417641) writes "The lynchpin of the investigation of the disappearance of Malaysia Airlines Flight 370 has been the pings from the plane to one of Inmarsat's satellites. The pings are the sole evidence of what happened to the plane after it slipped out of radar contact. Without them, investigators knew only that the plane had enough fuel to travel anywhere within 3,300 miles of the last radar contact—a seventh of the entire globe. Inmarsat concluded that the flight ended in the southern Indian Ocean, and its analysis has become the canonical text of the Flight 370 search. It's the bit of data from which all other judgments flow—from the conclusive announcement by Malaysia's prime minister that the plane has been lost with no survivors, to the black-box search area, to the high confidence in the acoustic signals, to the dismissal by Australian authorities of a survey company's new claim to have detected plane wreckage. But scientists and engineers outside of the investigation have been working to verify Inmarsat's analysis and many say that it just doesn't hold up."
Re:Not so.... (Score:5, Informative)
The problem with this analysis is that the Doppler "spike" would not have come from a due South trajectory. It is most likely to have come from a change of trajectory almost directly towards teh satellite. The implication is that this was a "ping" that just happened to have occurred during a turning manouevre; given that the SATCOM terminal on the aircraft uses a high-gain steerable antenna, it is not surprising that an "unscheduled" ping took place during a turn, as the beam-steering unit reacquired the satellite.
The other massive confounder with this analysis is that the SATCOM terminal necessarily pre-compensates its transmissions for Doppler shift. The channel bandwidth in the Inmarsat Classic Aero system is sufficiently narrow that when received at the Satellite, the center frequency must be +/-250 Hz of nominal. As Doppler shift due to the expect motion of an aircraft is in the region of +/- 800 Hz, this can only be done by active pre-compensation.
You'll notice from the Inmarsat Data that the uncorrected Doppler shift is within 250 Hz of expected, indicating that some pre-compensation is present.
Without details of how the compensation works, analysis is very difficult, if not impossible. A scan of the patent literature suggests that both measured-Doppler compensation (i.e. the aircraft terminal measures Doppler shift on a satellite broadcast channel, and applies an equivalent compensation on its transmissions) and estimated Doppler compensation (i.e. the satellite terminal communicates with the aircraft's navigation reference unit to obtain heading, and velocity information, and then computes an expected Doppler shift which is applied to transmissions) may be in use.
Re:The explanation is simple (Score:0, Informative)
but, but, but fire cannot melt metal! This is how we know blacksmiths use their amazing psychic powers to soften metal, and the whole "forge" thing was just part of the cover-up!
Sheesh. You know, I love a good conspiracy theory but the Truthers couldn't even tell an entertaining story, even if you excuse their lack of understanding of middle-school science.
Hey dipshit: fire did not cause Building 7 to collapse. It was destroyed by demolition. Get a clue.
Re:What were the pings then? (Score:2, Informative)
What nobody seemed to be asking is why they never got even two consecutive pings, plus the locations where they heard the pings seemed to be literally all over the map.
Uh, what?
They heard pings in one area approximately every second for about two hours, and in other areas for shorter periods. So that's over seven thousand consecutive pings. And the ares they heard the pings were within a few kilometres of each other.
There's no question that they received signals consistent with the aircraft black box underwater beacon, only whether it was the aircraft black box underwater beacon or something else.
Re:Spy games (Score:5, Informative)
The why not is an easy one - spy satellites are put into orbits which cover the likely hotspots for their use, and changing those orbits lessens the useful life of the satellite fairly significantly.
Oh, and no one really wants to give away the true capabilities of their spy satellites...
Re:The explanation is simple (Score:5, Informative)
But that's the point, of course. Blacksmiths don't (usually) melt the metals they work with, just soften them a bit. And the construction of the various WTC buildings of course depended on the rigidity of the steel they were built with (in different ways in the different buildings).
Did you know there's a technical term for materials that, rather than melting with an abrupt state change, go through a long transition becoming gradually more plastic and malleable? We call those "metals".
Supposedly confirmed from other flights (Score:4, Informative)
The company claimed that they have confirmed their methodology using data from other airplanes flying in similar area.
Re:Simpler: Electrical Fire (Score:4, Informative)
None of the electronics went off before their last communication. Where is your source for that? There were alot of blogs that assumed that since the last Acars signal was at 1:07 am and the last communication, "Good night Malaysian three seven zero", was at 1:19am it was turned off. However that means nothing since Acars works in 30 min increments so it's next message wouldn't have been till 1:37 am. The system could have failed anytime between 1:19am and 1:37am.
Cell phones would not [slate.com] have been able to work at that distance and speed.
The flight's satellite phones wont work if eletronics are off.
Re:Given all the spy satelites pointed at hotspots (Score:4, Informative)
The number of suitable hangars with suitable runways to land on nearby is pretty limited. Maybe all of them should simply be checked.
That's been considered, and I assume the checks would already have been completed.
You can see all the known runways on this map: http://i.imgur.com/Iwa6Ali.jpg [imgur.com]
The rest of the discussion here is interesting as well. http://www.flyertalk.com/forum... [flyertalk.com]
Re:The explanation is simple (Score:5, Informative)
Just replying so that anyone else reading this isn't suckered in by your mistakes or ignorance:
1. Steel gets 'soft' enough between 500 and 700 DeC to lose most of its structural properties.
2. A typical fire - like something that could start in an office - can easily get to 700+ DegC. This includes the gas coming off the fire.
3. A bit of jet fuel could easily set most things inside an office building alight.
Source - I design buildings not to fall over in a fire.
play Jenga to find out, or turn on your stove (Score:5, Informative)
More specifically, it collapsed as though the FIRST floor could no longer support the weight of the entire building on top of it. You can see that in the videos.
You can see the exact same thing in your kitchen if you have a gas stove. I know it's more fun to read spy stories than to actually try an experiment, but just know that I'm going to ignore any replies from you until you try the experiment yourself.
Go get a few wire coat hangers or similar metal wire, and some pans. In your kitchen, set up some wire supports to hold a pan four inches above the flame. Try to make the supports symmetrical, like the way a professional building would be designed. Pretend that the wire costs a million dollars per inch, so you'll use the minimum amount of wire necessary to hold the pan up. A bundt cake pan or something with a central opening would be the best simulation, simulating the center elevator columns.
Also keep in mind WTC 7 was tricky to design because the first couple of floors were built around / over an existing power station, so it was designed to use fewer, stronger supports than most buildings would. (You can't put a 40' wide support column right through a part of the power station).
Once the first pan is in place, add three more "floors" (pans), so you have four or more floors, each a few inches apart.
Now tturn the fire on high and wait 5-15 minutes. What Wil happen is that the heat will soften the metal supports just a bit at first, then more so as they heat up. At some point (as high as 500-600 degrees), they'll get soft enough that they collapse under the weight of all those pans. The stack will drop, just like WTC 7.
I KNOW yyou want to argue with me right now. That's cool, you can do that. But first, go in your kitchen and give it a try. Then you can argue from actual knowledge as opposed to repeating silly ghost stories about topics you're unfamiliar with.