Malaysian Airlines MH370 contact lost
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I think one thing that may have been overlooked, is how far north of Banda Aceh the plane would have had to have flown to avoid Indonesian radar (they said they didnt track it)....So, if we concluded and calculated that the plane ended it's trip sometime not long after the partial handshake, it was in the air for a total flight time of somewhere around 7.38 to *unknown* extra minutes. Let's "speculate" that it was 8hrs. We "conclusively" know about 1:34 (initial flight and turn back), which takes us over Pualu Perek. What we dont know is how long the flight continued north so as to avoid turning over Indonesia. If we said "okay...30 minutes" and then turned south...that takes off 2:00, leaving remaining flight time of somewhere around 6 hours. Lets then "speculate" that the plane turned somewhere 300km past Indonesia, so as to avoid Indonesian radar. "If" the plane maintained a speed of 850kmh (only saying that as it seems a lower flight level=lower speed and it "may" have lowered its flight level according to the reports), then "unknown" travel (after disappearing!) would be somewhere near 5100km....Take off 300km (avoidance of Indonesian radar), then its 4800km. That would mean the crash zone could not be below Perth....Actually somewhere west of Geraldton would be closer.
I understand that this is all "speculation", but so is pretty much everything else at this point
I understand that this is all "speculation", but so is pretty much everything else at this point
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One thing we do not know which may have affected the range of the aircraft is exactly how far WNW it flew from Butterworth. It appeared to drop off primary radar at 200nm. Further elucidation of this may have been possible by data collected by other agencies not disclosed for security reasons.
However, if this is so, it does make it even more confusing that the final position appears to be closer to Perth. It would help to explain the time and speed, however.
However, if this is so, it does make it even more confusing that the final position appears to be closer to Perth. It would help to explain the time and speed, however.
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Mises,
Not impossible at all when you consider that the only thing they have to work with is the Doppler shift values.
When you have only the Doppler shifts, the only thing you know is the speed of the aircraft RELATIVE TO the satellite. You don't know the distance between the two, and nor do you know precisely the track of the aircraft.
You can estimate a track, based on an assumption of the aircraft's true speed. If you assume a different speed, however, then the entire track direction changes, as does each ping position along it.
If the estimated track had stayed the same, then I would agree with your "impossible" claim. But note that they have come up with a new track.
But, the current location is shorter than the previously estimated position for a KNOWN TIME 8.11, which was based on a slower speed. That's impossible.
When you have only the Doppler shifts, the only thing you know is the speed of the aircraft RELATIVE TO the satellite. You don't know the distance between the two, and nor do you know precisely the track of the aircraft.
You can estimate a track, based on an assumption of the aircraft's true speed. If you assume a different speed, however, then the entire track direction changes, as does each ping position along it.
If the estimated track had stayed the same, then I would agree with your "impossible" claim. But note that they have come up with a new track.
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No, in less time.
He was out of fuel sooner. The last ping really doesn't define when exactly flight ended, we don't have this data, not yet.
He was out of fuel sooner. The last ping really doesn't define when exactly flight ended, we don't have this data, not yet.
They flew faster for a shorter distance still doesn't pan out.
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Maybe I have missed something but it seems that calculations of final position based on satnav pings is assuming the signal received at the satellite is strictly Line Of Sight, which may not be the case. There is a well known phenomena called Tropospheric Ducting
E-skip, tropospheric ducting and other VHF propagation phenomena « Engineering Radio
,amongst a few other VHF propagation effects that typically occur in areas of temperature inversions (warmer air above cooler air). Under these conditions VHF signals can travel far beyond LoS range making it nearly impossible to determine the position of the transmitting station.
As a young amateur radio operator I remember holding a conversation with a man in Houston from my apartment in Austin (~200km) using a low power 146 MHz walkie talkie. Since then I have listened to conversations between two people in Louisiana as clear as if they were across the neighborhood as well as an equivalent discussion originating in Oklahoma.
There is a chance, no matter how remote, that the emissions from MH370 could have been caught in a tropo duct for a considerable distance and emerge generally pointed skyward where the satellite picks it up. In that case the ping timing calculated doppler effect may point to a spot the actual aircraft never passed through.
E-skip, tropospheric ducting and other VHF propagation phenomena « Engineering Radio
,amongst a few other VHF propagation effects that typically occur in areas of temperature inversions (warmer air above cooler air). Under these conditions VHF signals can travel far beyond LoS range making it nearly impossible to determine the position of the transmitting station.
As a young amateur radio operator I remember holding a conversation with a man in Houston from my apartment in Austin (~200km) using a low power 146 MHz walkie talkie. Since then I have listened to conversations between two people in Louisiana as clear as if they were across the neighborhood as well as an equivalent discussion originating in Oklahoma.
There is a chance, no matter how remote, that the emissions from MH370 could have been caught in a tropo duct for a considerable distance and emerge generally pointed skyward where the satellite picks it up. In that case the ping timing calculated doppler effect may point to a spot the actual aircraft never passed through.
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as the APU and/or RAT took over electrical generation (causing the satcom to re-set and send a new initial handshake request).
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tropopause
It is all at lower altitudes if the plane was above 20,000 would not have any affect as signals would be going up at 15-25 degrees not down to the sea, air is dry and rh is very low (basic met) SALR DALR
If the sat was low on horizon maybe could like when you look and see the black inversion layer but above an inversion layer signals are refracted up not down
If the sat was low on horizon maybe could like when you look and see the black inversion layer but above an inversion layer signals are refracted up not down
When you have only the Doppler shifts, the only thing you know is the speed of the aircraft RELATIVE TO the satellite. You don't know the distance between the two, and nor do you know precisely the track of the aircraft.
The combination of changing ping time and doppler gives further information, but does not appear to be sufficient to identify a single location without assumptions about speed, fuel, and altitude.
It's all going into a mathematical model. When some of the assumptions (variables in the equation) change, the results change.
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Ping Circles
If the last 3 ping circles are known, then assuming reasonably constant speed, altitude and direction, there will be 3 equidistant intersecting points along the actual path which can be found on those circles.
No need for doppler measurements.
Anyone see a problem with this geometrical method?
No need for doppler measurements.
Anyone see a problem with this geometrical method?
The consequences of the laws of physics can sometimes be counterintuitive.
Faster does not necessarily mean further.
In nil wind conditions, any airspeed above the aircraft's best range speed will result in shorter range.
Much faster equals much shorter.
Faster does not necessarily mean further.
In nil wind conditions, any airspeed above the aircraft's best range speed will result in shorter range.
Much faster equals much shorter.
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time and position
01:34 02:15 18:15 Last primary radar contact by Malaysian military, 200 miles (320 km) NW of Penang
Props are for boats!
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Olasek,
I agree the SATCOM makers who ever they are being Rockwell Collins, Honeywell, etc, will know the reason and the logic behind that last partial ping. We don't know yet. Let's hope they have an answer and are being called upon by the investigation team...
Only if you believe that partial ping had anything to do with running out fuel, I personally see little confirmed evidence of that.
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buttrick (03:47):
From the published chart the six "pings" before the 00:11 read on the chart at:
~18:25, ~18:28, 19:40, 20:40, 21:40 and 22:40. They are not every hour, as written everywhere:
Is any body have an idea why there are 3 pings in about five minutes around the time the plane ("possibly") turn south?
01:30 02:11 18:11 First of seven automated hourly Classic Aero pings (handshakes) (since last ACARS transmission) via the Inmarsat-3 F1
~18:25, ~18:28, 19:40, 20:40, 21:40 and 22:40. They are not every hour, as written everywhere:
Is any body have an idea why there are 3 pings in about five minutes around the time the plane ("possibly") turn south?
Last edited by Shadoko; 29th Mar 2014 at 03:53. Reason: Add "possibly"
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Only if you believe that partial ping had anything to do with running out fuel, I personally see little confirmed evidence of that.
Pure speculation.
Pure speculation.
It would be exactly the sort of consequence of the gennys going off-line and RAT or APU coming on line.
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time and position
Assuming that the "last radar return" is true, (it is possible that the military radar had labelled a different aircraft at the IGARI waypoint).
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I'm really questioning the primary returns at GIVAL and IGREX
But I think you have to be reasonable. Every piece of info, every map analyzing possible tracks shows all tracks converging at IGREX, this seems to be an undisputed origination point for the tracks heading South. I haven't seen any mention that it could still be disputed.
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They just had a plane and 239 people disappear on their watch. Despite the fact that no physical evidence has been found, the Malaysian President said the plane is destroyed and all the passengers are dead. A profoundly disturbing conclusion like this needs a better explanation than "oh some clever satellite guys in England worked it out."
They have a duty to explain this conclusion in excruciating detail, not just morally, but legally under agreements signed under the auspices of the ICAO.
Personally, I don't doubt the conclusion that the a/c is somewhere in the Indian Ocean, but I am starting to doubt the Malaysian authorities competence and commitment to transparency in this investigation.