Malaysian Airlines MH370 contact lost
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Even if the currents were at a leisurely walk of 3 Knots x 24 hours in a day (currents never sleep) = Debris Field 72 miles from ditching / impact in just one day
It is now going on 15 days since MH370 went missing
15 days x 72 miles = 1080 NM from ditching / impact
Now going back to basic pilot trainer class if you are one degree off course in 60 miles you will be one mile off course.
1080 / 60 = 18 miles plus or minus the debris field could be located with just one degree change in the ocean currents vs. those who plot the currents.
All of these numbers could be multiplied by two or three with all the verbals in the Southern Indian Ocean.
It is now going on 15 days since MH370 went missing
15 days x 72 miles = 1080 NM from ditching / impact
Now going back to basic pilot trainer class if you are one degree off course in 60 miles you will be one mile off course.
1080 / 60 = 18 miles plus or minus the debris field could be located with just one degree change in the ocean currents vs. those who plot the currents.
All of these numbers could be multiplied by two or three with all the verbals in the Southern Indian Ocean.
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Apart from hypoxia, are there any other scenarios that would account for the crew and passengers being incapacitated AND the plane being able to fly for another 5-7 hours?
Freight God
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Primary radar can be used to compute distance as it would be proportional to the transit time taken by a pulse of energy to travel to the object and back again. As they have azimuth, they may be also have SOME elevation resolution.
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that to me says you think they searched there because of the arc.
You also still seem to think it flew all along one of these arcs it did not.
It was seen on malay and Thai mil primary radar and the Malayasia track was confirmed later
If you think mil radar will not pick up unidentified planes please explain why they have them!
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Current military primary surveillance radar DOES provide altitude
For all who think that primary radar cannot indicate altitude, please look up the SPS-48 - which entered service in the U.S. Navy over 50 YEARS ago and is just a typical example of a long range 3-D radar type.
Phased array 3-D surveillance radars are common in military air defense service as we really don't like to just have interceptors go wandering around trying to determine if the bogey target is at 10K or FL450.
Now, the fair point here is that the height accuracy is definitely affected by the target range, but less than ~4K foot altitude error at 200 nm range is definitely common.
(Lonewolf50 - I was on the design team for the NTU many, many years ago. It's good to see it spoken of well.)
Phased array 3-D surveillance radars are common in military air defense service as we really don't like to just have interceptors go wandering around trying to determine if the bogey target is at 10K or FL450.
Now, the fair point here is that the height accuracy is definitely affected by the target range, but less than ~4K foot altitude error at 200 nm range is definitely common.
(Lonewolf50 - I was on the design team for the NTU many, many years ago. It's good to see it spoken of well.)
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Originally Posted by BOAC 
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Yes, everyone, I do understand the margins of error (as yet unknown) on this '40 degree arc', but I still reckon that the odds of the a/c tracking ACROSS the arcs and at least one ping being at some other angle would be high.
A very valid point, why would anyone navigate along a route exactly the same distance (elevation) from a satellite?
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Yes, everyone, I do understand the margins of error (as yet unknown) on this '40 degree arc', but I still reckon that the odds of the a/c tracking ACROSS the arcs and at least one ping being at some other angle would be high.
A very valid point, why would anyone navigate along a route exactly the same distance (elevation) from a satellite?
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Originally Posted by MB
The 40 degree arc is based upon the altitude of the plane at the LKP.
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Re Satellite imagery
Just watching a BBC News interview with David Mearns (Blue Water Recoveries Ltd), expert in marine recovery. He was describing where the search may be directed now, assuming drift, and comparisons with the locations of the Australian and Chinese imagery. Also using current information to work backwards to calculate a predicted area for any original ditching.
When asked that all this assumes the material photographed is positively identified as part(s) of MH370, he implied the Australians and Chinese would not be chasing things likely to have another obvious origin.
When asked that all this assumes the material photographed is positively identified as part(s) of MH370, he implied the Australians and Chinese would not be chasing things likely to have another obvious origin.
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Inmarsat tell us the pings were 'all' at 40 degree elevations. Since we know where the first ping was transmitted (roughly), please explain how it got to the SIS, pinging at the same elevation all 7 times without tracking along the arc?
Either that or I do not understand the criticism.
Few possible routes - given several Inmarsat arcs
@awblain
RichardC10 has posted that he has used computer simulation to determine that if a set of several Inmarsat arcs is available then if a constant course is assumed then two unique track can be obtained - one for each hemisphere.
http://www.pprune.org/rumours-news/5...ml#post8386704
says:
I have the impression that Mr RichardC10 is cluefull.
In my view the whole post is worth a careful read.
the number of possible routes likely isn't very large.
http://www.pprune.org/rumours-news/5...ml#post8386704
says:
The result is that there is only one constant heading course from the last recorded radar position that matches the example set of ping arcs, that is the destination is uniquely defined by the interim and final ping arcs (if interim arcs exist). There is a (rough) mirror course in the southern hemisphere which may be hard to distinguish as the last recorded radar position was close to the equator.
In my view the whole post is worth a careful read.
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BOAC
they had a track but were not certain it was 370, they tracked it to the straits of malacca until losing contact.
The fact that it was 370 was confirmed at a mid week conference by the minister based on a variety of data, so your sleepy byes argument is like most of your argument -rubbish
- read the posts in this thread and you will see. Half+ the mil probably asleep at the wheel at the time. Oh, do ask the Russians who popped a Badger up in the Firth of Forth a few years back....................... :-)
The fact that it was 370 was confirmed at a mid week conference by the minister based on a variety of data, so your sleepy byes argument is like most of your argument -rubbish
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Primary radar can be used to compute distance as it would be proportional to the transit time taken by a pulse of energy to travel to the object and back again. As they have azimuth, they may be also have SOME elevation resolution.
http://upload.wikimedia.org/wikipedi...a/Mps-16-1.jpg
To track position of plane like T7 at FL 300+ and distance about 200nm was very easy. Blips were clear and you could see them in a second on the screen.
Last edited by Karel_x; 22nd Mar 2014 at 17:55.
Keeping Danny in Sandwiches
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Inmarsat
I understand that the arcs are based on the time difference between TX and RX of the signal from the satellite. Would such a signal frequency experience doppler shift if the aircraft was travelling towards or away from the satellite?
The other inference of the aircraft ACARS responding to the satellite is that there must have been power on that particular bus.
I understand that the arcs are based on the time difference between TX and RX of the signal from the satellite. Would such a signal frequency experience doppler shift if the aircraft was travelling towards or away from the satellite?
The other inference of the aircraft ACARS responding to the satellite is that there must have been power on that particular bus.
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Confused?
BOAC:
What is the basis of your assertion concerning what Inmarsat has said? I don't believe I've seen any such statement. Have I missed something?
A massive search effort is being expended ON THE 40 DEGREE ARC at supposed fuel exhaustion point. Inmarsat tell us the pings were 'all' at 40 degree elevations. Since we know where the first ping was transmitted (roughly), please explain how it got to the SIS, pinging at the same elevation all 7 times without tracking along the arc?
MB, Its the intersection of two spherical surfaces. One being the earths surface the other being the locus of all points a certain distance from the satellite based on signal travel time.
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MB - I don't think you understand the 40 degree elevation actually. Work out please (someone did it way back here) what difference a 6nm change in altitude would make in angular terms over a distance of 22000nm +? Un-measurable, I suggest. Altitude has very little to do with it. The 'red arcs' are probably drawn as ground position but would be near as dammit the same at 40,000' - a 3-D 'corridor' if you like.
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Originally Posted by oldb
was confirmed at a mid week conference by the minister based on a variety of data
I remain totally unconvinced so far of any 'stated facts' - except LKP and the 'essence' of the Inmarsat man's words. Everything else is 'subject to'. You, of course, are entiltled to believe all statements from Malaysia.
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Apart from hypoxia, are there any other scenarios that would account for the crew and passengers being incapacitated AND the plane being able to fly for another 5-7 hours?
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The terminal probably has to correct for doppler shift, because low bit-rate channels are very narrow; doesn't take much of a frequency shift to end up transmitting on or listening to an adjacent channel. There's a lot more flexibility in timing, which presumably explains why it doesn't try to correct for that.