Malaysian Airlines MH370 contact lost
Join Date: Apr 2008
Location: Paris
Age: 74
Posts: 275
Likes: 0
Received 0 Likes
on
0 Posts
About 50M to pay out for 239 passengers. Sounds like a bargain by western standards. Certainly not something that will hurt the bottom line of the insurers. I wonder whether the airline also gets a similar discount for the plane?
I feel really sad for the relatives, they got shoddy treatment from beginning to end, no hard information, no closure, laughable compensation. Let's hope their government doesn't retaliate in kind if something similar happens on their territory.
I feel really sad for the relatives, they got shoddy treatment from beginning to end, no hard information, no closure, laughable compensation. Let's hope their government doesn't retaliate in kind if something similar happens on their territory.
Join Date: May 2011
Location: UK
Age: 61
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
$50k is (as the title says) just an interim payment. The Montreal Convention limit is $175k, but unlimited if Malaysian can't prove it wasn't their fault (reverse burden of proof).
Join Date: Apr 2014
Location: Washstate
Age: 79
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
Inmarast confident in Hot spot
BBC News - Malaysian MH370: Inmarsat confident on crash 'hotspot'
The UK satellite company Inmarsat has told the BBC that the search for the missing Malaysia Airlines jet has yet to go to the area its scientists think is the plane's most likely crash site.
Inmarsat's communications with the aircraft are seen as the best clues to the whereabouts of Flight MH370.
The hunt for the lost jet is currently taking a short break while ships map the Indian Ocean floor.
When the search resumes, the Inmarsat "hotspot" will be a key focus.
But so too will a number of areas being fed into the investigation by other groups.
Australian authorities are expected to announce where these are shortly.
--- goes on . . .
The UK satellite company Inmarsat has told the BBC that the search for the missing Malaysia Airlines jet has yet to go to the area its scientists think is the plane's most likely crash site.
Inmarsat's communications with the aircraft are seen as the best clues to the whereabouts of Flight MH370.
The hunt for the lost jet is currently taking a short break while ships map the Indian Ocean floor.
When the search resumes, the Inmarsat "hotspot" will be a key focus.
But so too will a number of areas being fed into the investigation by other groups.
Australian authorities are expected to announce where these are shortly.
--- goes on . . .
Join Date: Mar 2014
Location: SW USA
Posts: 67
Likes: 0
Received 0 Likes
on
0 Posts
INMARSAT Claim
BBC News - Malaysian MH370: Inmarsat confident on crash 'hotspot'
"The UK satellite company Inmarsat has told the BBC that the search for the missing Malaysia Airlines jet has yet to go to the area its scientists think is the plane's most likely crash site."
" the Ocean Shield ship never got to the Inmarsat hotspot because it picked up signals some distance away that it thought were coming from the jet's flight recorders."
"By modelling a flight with a constant speed and a constant heading consistent with the plane being flown by autopilot - the team found one flight path that lined up with all its data.
'We can identify a path that matches exactly with all those frequency measurements and with the timing measurements and lands on the final arc at a particular location, which then gives us a sort of a hotspot area on the final arc where we believe the most likely area is," said Mr Ashton."
The article doesn't provide coordinates of the alleged "hotspot".
"The UK satellite company Inmarsat has told the BBC that the search for the missing Malaysia Airlines jet has yet to go to the area its scientists think is the plane's most likely crash site."
" the Ocean Shield ship never got to the Inmarsat hotspot because it picked up signals some distance away that it thought were coming from the jet's flight recorders."
"By modelling a flight with a constant speed and a constant heading consistent with the plane being flown by autopilot - the team found one flight path that lined up with all its data.
'We can identify a path that matches exactly with all those frequency measurements and with the timing measurements and lands on the final arc at a particular location, which then gives us a sort of a hotspot area on the final arc where we believe the most likely area is," said Mr Ashton."
The article doesn't provide coordinates of the alleged "hotspot".
Join Date: Oct 2007
Location: France
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
If the similitude is from a log-on, and you are probably right, why the first happened? The second have been associated with a possible flame-out and the start of the APU for a time long enough for the AES to come on line. But then, if the Satcom had been shut down sometimes after 17:07 (failed for any raison, or shut down to "fly in silence"?), what could have been the raison of the unit to go live again?
I understand from what happened later, that a "ping" was due around 08:07 (because the one hour timer). Was this "Log Control - Log-on Interrogation" (from the GES) canceled because there was no answer to other requests around 18:03? Or it is because someone tried to join the aircraft by the Satphone that THE "pings" happened?
Another consideration: from the graph below, one can see that the BTOs of R-Channel and T-Channel are, for each, very consistent, whatever unit is used:
And there is a ~5000 microseconds difference between them (4987 is the average of the BTO differences of each time the RX alternate between R and T along the timeline).
The BTO for T-Channel when the aircraft was in KL (9800 microseconds at 16:00:28) is too small for a signal could reach any point on a line below the satellite (at this time, it takes ~13560 microseconds for the light between KL and and a point at Earth surface below 3F1). Could the published BTOs for T-Channel be computed in another way that R-Channel?
OK, enough questions...
I understand from what happened later, that a "ping" was due around 08:07 (because the one hour timer). Was this "Log Control - Log-on Interrogation" (from the GES) canceled because there was no answer to other requests around 18:03? Or it is because someone tried to join the aircraft by the Satphone that THE "pings" happened?
Another consideration: from the graph below, one can see that the BTOs of R-Channel and T-Channel are, for each, very consistent, whatever unit is used:
And there is a ~5000 microseconds difference between them (4987 is the average of the BTO differences of each time the RX alternate between R and T along the timeline).
The BTO for T-Channel when the aircraft was in KL (9800 microseconds at 16:00:28) is too small for a signal could reach any point on a line below the satellite (at this time, it takes ~13560 microseconds for the light between KL and and a point at Earth surface below 3F1). Could the published BTOs for T-Channel be computed in another way that R-Channel?
OK, enough questions...
Join Date: Mar 2014
Location: N. California
Age: 80
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
I would love to know what speed they believe it flew at.
When I plot a track from POVUS to the area of the Ocean Shield search I come up with a ground speed of about 300kts.
When I plot a track from POVUS to the area of the Ocean Shield search I come up with a ground speed of about 300kts.
Join Date: Oct 2007
Location: France
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
When the "Raw data" were published, there was also some maps with speeds indicated for each path. There is a copy of the different documents there:
https://drive.google.com/folderview?...kk&usp=sharing
The original doc was named "MH370 - Maps.pdf" and the only other info in the doc is the "name" of the author : UUU.
https://drive.google.com/folderview?...kk&usp=sharing
The original doc was named "MH370 - Maps.pdf" and the only other info in the doc is the "name" of the author : UUU.
Join Date: Jun 2009
Location: Canada
Posts: 464
Likes: 0
Received 0 Likes
on
0 Posts
I think so. I believe the aircraft can transmit at any time on the R-channel, but is assigned specific timeslots on the T-channel (you can see T-channel assignment messages in the logs). So the logged offset is probably the offset from the assigned timeslot, and the logs presumably show the aircraft transmitting a few milliseconds before it was supposed to.
Join Date: Apr 2014
Location: usa
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
R-Channel and T-Channel
The Inmarsat notes state that they only used the R-Channel BTO values. But, as you look through the Released Data, there and many many more data points that were ignored. If you plot all of the R-Channel BTO values, along with all of the (T-Channel BTO + 5000uSec), they line up extremely well.
With all of the data plotted on a chart you will also see the jitter, or noise, at each point in time is a spread of 60uSec to 80uSec with one especially noisy period with a spread of 120uSec (16:06-16:09UT sitting at the gate...). Keep that in mind when considering what resolution we should expect after converting signal latency to a ring, arc, or even a specific physical location.
The BTO numbers are offset (reference to the 'nominal terminal' in the notes). The key is simply to calibrate the measured time to the known location(s) at the gate (16:00-16:30 or even 16:41) and while ADS-B data is available (16:42-17:07UT). The BTO reflects the round trip time GES-satellite-AES, after subtracting the time to the nominal terminal location (GES-satellite-NomTerm).
{for those into the details, the 1st tricky part is that the earth is not round... So, converting from BTO to elevation angle and then to 'ping rings' gets complicated bu the true 'flattened' shape of the earth}
{The second tricky part is deciding where the 'real' satellite is used Vs. where the idealized fixed representation of the satellite is used... Because that affects the calculated elevation angle }
-Bill
<<edited to correct the sign in my equation above. - T-Channel BTO values are lower than R-Channel BTO by 5mS, so to align them, I should have written (T-Channel BTO + 5000uSec).>>
With all of the data plotted on a chart you will also see the jitter, or noise, at each point in time is a spread of 60uSec to 80uSec with one especially noisy period with a spread of 120uSec (16:06-16:09UT sitting at the gate...). Keep that in mind when considering what resolution we should expect after converting signal latency to a ring, arc, or even a specific physical location.
The BTO numbers are offset (reference to the 'nominal terminal' in the notes). The key is simply to calibrate the measured time to the known location(s) at the gate (16:00-16:30 or even 16:41) and while ADS-B data is available (16:42-17:07UT). The BTO reflects the round trip time GES-satellite-AES, after subtracting the time to the nominal terminal location (GES-satellite-NomTerm).
{for those into the details, the 1st tricky part is that the earth is not round... So, converting from BTO to elevation angle and then to 'ping rings' gets complicated bu the true 'flattened' shape of the earth}
{The second tricky part is deciding where the 'real' satellite is used Vs. where the idealized fixed representation of the satellite is used... Because that affects the calculated elevation angle }
-Bill
<<edited to correct the sign in my equation above. - T-Channel BTO values are lower than R-Channel BTO by 5mS, so to align them, I should have written (T-Channel BTO + 5000uSec).>>
Join Date: Mar 2014
Location: N. California
Age: 80
Posts: 184
Likes: 0
Received 0 Likes
on
0 Posts
@Shadoko
Thanks for the link.
The map also shows speeds in the low 300kt range.
Isn't maximum range speed higher than this for a 772?
Why would it be flying so slow?
Thanks for the link.
The map also shows speeds in the low 300kt range.
Isn't maximum range speed higher than this for a 772?
Why would it be flying so slow?
Join Date: Oct 2009
Location: Australia
Posts: 367
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: May 2011
Location: UK
Age: 61
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Good grief - they searched where they did because they (thought they had) detected ULB pings. Even if the pings didn't turn out to be from MH370, it would have been pretty stupid to have swanned off to the Inmarsat "most probable" location, while meanwhile the ULB batteries would have died in a "less probable" location.
This hindsight-enhanced armchair second-guessing of a very professional search team gets a bit ridiculous at times.
This hindsight-enhanced armchair second-guessing of a very professional search team gets a bit ridiculous at times.
Join Date: May 2006
Location: London
Age: 69
Posts: 237
Likes: 0
Received 0 Likes
on
0 Posts
This morning's Guardian has an article based tonight's BBC Horizon programme - it states that Inmarsat believe the "hot-spot" is further south and west from the area that was searched.
This is the article ;
MH370: searchers not looking in the best place, satellite experts say | World news | theguardian.com
This is the key bit ;
"It was by no means an unrealistic location but it was further to the north east than our area of highest probability," Chris Ashton at Inmarsat told Horizon.
Experts from the satellite firm modelled the most likely flight path using the hourly pings and assuming a speed and heading consistent with the plane being flown by autopilot.
"We can identify a path that matches exactly with all those frequency measurements and with the timing measurements and lands on the final arc at a particular location, which then gives us a sort of a hotspot area on the final arc where we believe the most likely area is," explained Ashton."
This is the article ;
MH370: searchers not looking in the best place, satellite experts say | World news | theguardian.com
This is the key bit ;
"It was by no means an unrealistic location but it was further to the north east than our area of highest probability," Chris Ashton at Inmarsat told Horizon.
Experts from the satellite firm modelled the most likely flight path using the hourly pings and assuming a speed and heading consistent with the plane being flown by autopilot.
"We can identify a path that matches exactly with all those frequency measurements and with the timing measurements and lands on the final arc at a particular location, which then gives us a sort of a hotspot area on the final arc where we believe the most likely area is," explained Ashton."
Join Date: Feb 2008
Location: UK
Posts: 66
Likes: 0
Received 0 Likes
on
0 Posts
A model for interpreting the BFO data
Over the last couple of weeks I have been developing an analysis of possible tracks for MH370. After adjustment for a very small cumulative frequency drift term during the flight (2Hz), the final results predict search areas very close to those published by the authorities.
I have written a paper on the analysis, posted here.
https://www.dropbox.com/s/ez4sxffxyl...14_issue_1.pdf
I have tried to be thorough but at the expense of being long. This was a lot of work – my wife thinks I am barmy!
The main progress on the system analysis that allows this level of analysis was on the nature of the mysterious D3 component. I have worked from the Inmarsat note with the data logs that stated it is related to the AFC system, plus some documents from Miteq that describe the Inmarsat AFC system. The conclusion is that D3 is related to the total Doppler shift on the pilot frequency used in the AFC system at Perth for the C-band downlink. This pilot frequency is generated (at L-band) at the TT+C ground station for Inmarsat 3F1 which is at Fucino, Italy (the so called primary ground station in the Miteq document). Because this is in the Northern hemisphere and Perth the Southern, the Doppler on the combined link is less than the C-band link to Perth alone. The combined Doppler can be calculated precisely. Details are in the paper.
The set of possible tracks used for the analysis is generated with two parameters, a) a speed for the leg from the turn-back point to the 18:29UT ping-ring, b) a different but constant speed for the rest of the legs. This is a parameterisation of the flight path, the speeds of the first part of the flight (before 19:41UT) can be adjusted without changing the conclusions, but the BFO and BTO data do not in themselves require that complication. This is again discussed in the document. I have not used any of the possible radar contacts with MH370 as a constraint on the model.
In general I have been trying to replicate and understand the analysis techniques that I believe the investigating authorities have used. The published work has always emphasised constant speeds, presumably on the basis of some analysis of the possible aircraft modes. I am not trying to second guess what the authorities have done.
I have used the chi-squared statistical test to judge whether models of the track can be excluded on the basis of the data. This is a quantitative test, rather than just picking the best fit. I don’t know what statistical tests the official analysis has used.
Comments are welcome of course.
I have written a paper on the analysis, posted here.
https://www.dropbox.com/s/ez4sxffxyl...14_issue_1.pdf
I have tried to be thorough but at the expense of being long. This was a lot of work – my wife thinks I am barmy!
The main progress on the system analysis that allows this level of analysis was on the nature of the mysterious D3 component. I have worked from the Inmarsat note with the data logs that stated it is related to the AFC system, plus some documents from Miteq that describe the Inmarsat AFC system. The conclusion is that D3 is related to the total Doppler shift on the pilot frequency used in the AFC system at Perth for the C-band downlink. This pilot frequency is generated (at L-band) at the TT+C ground station for Inmarsat 3F1 which is at Fucino, Italy (the so called primary ground station in the Miteq document). Because this is in the Northern hemisphere and Perth the Southern, the Doppler on the combined link is less than the C-band link to Perth alone. The combined Doppler can be calculated precisely. Details are in the paper.
The set of possible tracks used for the analysis is generated with two parameters, a) a speed for the leg from the turn-back point to the 18:29UT ping-ring, b) a different but constant speed for the rest of the legs. This is a parameterisation of the flight path, the speeds of the first part of the flight (before 19:41UT) can be adjusted without changing the conclusions, but the BFO and BTO data do not in themselves require that complication. This is again discussed in the document. I have not used any of the possible radar contacts with MH370 as a constraint on the model.
In general I have been trying to replicate and understand the analysis techniques that I believe the investigating authorities have used. The published work has always emphasised constant speeds, presumably on the basis of some analysis of the possible aircraft modes. I am not trying to second guess what the authorities have done.
I have used the chi-squared statistical test to judge whether models of the track can be excluded on the basis of the data. This is a quantitative test, rather than just picking the best fit. I don’t know what statistical tests the official analysis has used.
Comments are welcome of course.
Keeping Danny in Sandwiches
Join Date: May 1999
Location: UK
Age: 76
Posts: 1,294
Likes: 0
Received 0 Likes
on
0 Posts
"It was by no means an unrealistic location but it was further to the north east than our area of highest probability," Chris Ashton at Inmarsat told Horizon.
The interesting point of this is that it is based on constant groundspeed. Have they been though the aloft winds for the 8th March and integrated them into the constant TAS to obtain a groundspeed (the track would be the same if it was on LNAV)?
Does anyone have access or a link to the actual winds aloft at that time, it could be an interesting line to follow?
Join Date: Apr 2014
Location: usa
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
A model for interpreting the BFO data
RichardC
Good work, and a great write-up... (I will have to finish reading it later.)
Comparing notes between different analysis might help each...
The rumor is that the Pilot signal is coming form an Earth station in Burum, Netherlands. (minor difference from Fucino, Italy)
The work Victor Iannello, Mike Exner, Duncan Steel, Don Thompson and others (as referenced: http://tmfassociates.com/MH370Jun8.pdf ) Is narrowing in on the rumor that the EAFC was incorrectly programmed as to the Lat/Lon location for the Perth ground station. A positive (Northern Lat) for Perth results in roughly 30% reduction in the sat-Perth correction.
In addition to the satellite data, there was reportedly (rumor 3?) an extensive analysis of the fuel range of the flight. The ACARS report at 17:07UT would have provided a fairly accurate fuel weight at that time. (Initial Fuel loads on the ground has been mentioned in the press, and some people done some analysis with those numbers. But, the later ACARS numbers would be more accurate.) The work presumed some truth to early reports that the plane flew erratic or evasive maneuvers West across the peninsula and NorthWest over the Straits {between the turnaround (just after 17:22UT) and the last radar blip (18:22UT)}. The working assumption was that fueld consumption was much higher than would have occurred for level cruise at FL350. {multiple extreme changes in altitude (>45000ft to <5000ft), terrain hugging, and avoiding Thai & Indonesian airspace...}
There was also a belief that the last radar blips established the speed and altitude of the plane at 8:22UT = low (2900ft) and slow (?)... But, my review of the radar blips indicates a much higher speed (~ 500kts ground speed) and altitude (over 35000ft to have been visible on radar at that distance). -- I believe (aka my opinion...) that the fuel exhaustion analysis based on the (overestimated) early flight fuel consumption and the (underestimated) low altitude & speed - pushed the most likely search zone far to the North and East along the 00:11UT arc ('ping ring').
Recent statements from Inmarsat and other participants in the official search effort seem to support the idea that the new search area will be along the same arc, but further South and West, closer to the initial Inmarsat projected paths.
One previously released image "Example Southern Tracks" shows a red line for a "Constant 400 Knts Track", and a yellow line for a "Constant 450 knts Track". With a little adjustment for other improvements they may have made to their BTO+BFO models (and possibly the addition of an even faster track) I am expecting the search area to be more in line with these early proposed tracks.
one person's 'rumor' may another persons 'fact'...
Good work, and a great write-up... (I will have to finish reading it later.)
Comparing notes between different analysis might help each...
The rumor is that the Pilot signal is coming form an Earth station in Burum, Netherlands. (minor difference from Fucino, Italy)
The work Victor Iannello, Mike Exner, Duncan Steel, Don Thompson and others (as referenced: http://tmfassociates.com/MH370Jun8.pdf ) Is narrowing in on the rumor that the EAFC was incorrectly programmed as to the Lat/Lon location for the Perth ground station. A positive (Northern Lat) for Perth results in roughly 30% reduction in the sat-Perth correction.
In addition to the satellite data, there was reportedly (rumor 3?) an extensive analysis of the fuel range of the flight. The ACARS report at 17:07UT would have provided a fairly accurate fuel weight at that time. (Initial Fuel loads on the ground has been mentioned in the press, and some people done some analysis with those numbers. But, the later ACARS numbers would be more accurate.) The work presumed some truth to early reports that the plane flew erratic or evasive maneuvers West across the peninsula and NorthWest over the Straits {between the turnaround (just after 17:22UT) and the last radar blip (18:22UT)}. The working assumption was that fueld consumption was much higher than would have occurred for level cruise at FL350. {multiple extreme changes in altitude (>45000ft to <5000ft), terrain hugging, and avoiding Thai & Indonesian airspace...}
There was also a belief that the last radar blips established the speed and altitude of the plane at 8:22UT = low (2900ft) and slow (?)... But, my review of the radar blips indicates a much higher speed (~ 500kts ground speed) and altitude (over 35000ft to have been visible on radar at that distance). -- I believe (aka my opinion...) that the fuel exhaustion analysis based on the (overestimated) early flight fuel consumption and the (underestimated) low altitude & speed - pushed the most likely search zone far to the North and East along the 00:11UT arc ('ping ring').
Recent statements from Inmarsat and other participants in the official search effort seem to support the idea that the new search area will be along the same arc, but further South and West, closer to the initial Inmarsat projected paths.
One previously released image "Example Southern Tracks" shows a red line for a "Constant 400 Knts Track", and a yellow line for a "Constant 450 knts Track". With a little adjustment for other improvements they may have made to their BTO+BFO models (and possibly the addition of an even faster track) I am expecting the search area to be more in line with these early proposed tracks.
one person's 'rumor' may another persons 'fact'...
Join Date: Apr 2014
Location: usa
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
BFO Graph midpoint line
Gysbreght,
The midpoint line would be heavily influenced by the satellite movement, and the relative direction of the plane from the satellite. The satellite movement is sinusoidal, and the impact of the plane's location is far from linear (also containing a at least two trig function dependencies).
The orange mid-track line should be drawn on top of the other lines up to the point where the two paths diverge (~18:28). As drawn, the section of the orange line 18:28-29:41 is too low. (although, correcting that gives the orange line two distinct turns...)
It is the satellite reversing direction around 19:41UT (as just one of the contributors to the BFO) that puts the turn in each of the possible tracks.
- If the plane is to the North of the satellite, the satellite changes from approaching to moving away.
- If the plane is South of the satellite, then the satellite changed from receding to approaching.
Combining in the other BFO contributions leads to the appearance that the North track turns at a different time (20:41) than the South track (19:41). But, the lines drawn between data points are NOT real... We only have discrete measurements, with no indication on the chart of the BFO values in between. If you model the intervening times and fill in the expected BFO values, the two lines show a better symmetry, with the line turning closer to the actual satellite reaching its Northernmost point. (quite close to 19:41UT).
The midpoint line would be heavily influenced by the satellite movement, and the relative direction of the plane from the satellite. The satellite movement is sinusoidal, and the impact of the plane's location is far from linear (also containing a at least two trig function dependencies).
The orange mid-track line should be drawn on top of the other lines up to the point where the two paths diverge (~18:28). As drawn, the section of the orange line 18:28-29:41 is too low. (although, correcting that gives the orange line two distinct turns...)
It is the satellite reversing direction around 19:41UT (as just one of the contributors to the BFO) that puts the turn in each of the possible tracks.
- If the plane is to the North of the satellite, the satellite changes from approaching to moving away.
- If the plane is South of the satellite, then the satellite changed from receding to approaching.
Combining in the other BFO contributions leads to the appearance that the North track turns at a different time (20:41) than the South track (19:41). But, the lines drawn between data points are NOT real... We only have discrete measurements, with no indication on the chart of the BFO values in between. If you model the intervening times and fill in the expected BFO values, the two lines show a better symmetry, with the line turning closer to the actual satellite reaching its Northernmost point. (quite close to 19:41UT).
Join Date: Apr 2014
Location: usa
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Shadoko,
(I have read many of your prior posts. Your understanding and explanations of what you understand have been very good.)
The 'are you still there' handshakes follow roughly an hour after the last contact, or contact attempt, from the ground to the plane. You are correct that the 17:07UT (probably the ACARS report to RR) would have set the 1 hour timer. Then the 18:03 and 18:05 attempts to send a text message to the flight crew would have reset the 1 hour timer. The SDU (satcom, satellite modem, ...) reset at 18:25 and the following activity through 18:28 would have rest the timer again. Then, the vice phone call attempt at 18:39 to 18:40:56.354 would have been the last timer reset leading up to the 19:41 handshake and the next three (20:41, 21:41, and 22:41).
Then, the next voice phone call attempt (23:13-23:15) reset the timer.
At 00:11 (00:10:58.000), the are-you-there handshake seems to be a little early. I have no explanation for that...
Just to complete the walk through the handshakes...
the SDU restarted (again) at 00:19. Only the initial log-in was completed.
The ground station then checks on the plane at 01:15:56.
(not exactly an hour... But, I have a theory on this one... Possibly the 00:11 log-in had not completed far enough to terminate the prior connection established at the prior log-in (18:25-28). The last contact from that communications session was the voice call attempt that ended at 23:15. ...and that would be an hour.
the ground station retries the are-you-there message few times (01:16:06 and 01:16:15), since the one at 01:15 was not answered.
(I have read many of your prior posts. Your understanding and explanations of what you understand have been very good.)
The 'are you still there' handshakes follow roughly an hour after the last contact, or contact attempt, from the ground to the plane. You are correct that the 17:07UT (probably the ACARS report to RR) would have set the 1 hour timer. Then the 18:03 and 18:05 attempts to send a text message to the flight crew would have reset the 1 hour timer. The SDU (satcom, satellite modem, ...) reset at 18:25 and the following activity through 18:28 would have rest the timer again. Then, the vice phone call attempt at 18:39 to 18:40:56.354 would have been the last timer reset leading up to the 19:41 handshake and the next three (20:41, 21:41, and 22:41).
Then, the next voice phone call attempt (23:13-23:15) reset the timer.
At 00:11 (00:10:58.000), the are-you-there handshake seems to be a little early. I have no explanation for that...
Just to complete the walk through the handshakes...
the SDU restarted (again) at 00:19. Only the initial log-in was completed.
The ground station then checks on the plane at 01:15:56.
(not exactly an hour... But, I have a theory on this one... Possibly the 00:11 log-in had not completed far enough to terminate the prior connection established at the prior log-in (18:25-28). The last contact from that communications session was the voice call attempt that ended at 23:15. ...and that would be an hour.
the ground station retries the are-you-there message few times (01:16:06 and 01:16:15), since the one at 01:15 was not answered.
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by enjineerin
probably the ACARS report to RR
Join Date: Feb 2008
Location: UK
Posts: 66
Likes: 0
Received 0 Likes
on
0 Posts
enjineerin
That's interesting, I will run the numbers on that.
I saw that idea but I don't think it is a starter. Inmarsat have been running this system for years - errors would have been sorted long since. The final output of the Ground station system has to correct for all the downlink Doppler before it gets to the Inmarsat control centre. Any error would cause the frequencies to float all over the place.
I am personally very dubious about any of the Malaysian radar data. The BFO analysis does not support it, that is, it does not show probable tracks that are consistent with it. The analysis is consistent with simple track solutions, not complex.
I await tonight’s BBC programme. However, the quotes so far seems to imply that Ocean Shield was starting its hydrophone search at the North end of the search area shown in the ICAO report, while we know the search by the Chinese Haixun 01 was at the South end of that area (in the green zone). If the Ocean shield was diverted, it was from carrying on its search South West along the ICAO report search areas, not even further South beyond those areas, I think. In the paper I speculate that the green zone is consistent with tracks that had a speed of 470kt on the first leg, that is the final reported speed for MH370, but this may be going too far.
The early Inmarsat maps did not seem to use the detailed BFO data. The aim then was to demonstrate the aircraft flew South rather than North. I think the search areas moved North as the BFO data analysis matured and, frankly, was believed by the authorities.
The speeds in the BFO analysis in my paper are not directly constrained by the fuel usage. I have taken a maximum speed of 500kt for the first leg to the 18:29UT ping arc, if only because the original speed was 470kt, but the BFO data does not allow any faster speed that 330kt for later legs even for the fits to the four BFO values that take it much further South. Unless the BFO data has been changed a large amount by later analysis, the higher speed tracks are not consistent with the data.
The BFO data is a tough constraint on possible tracks, at least for simple track models.
The rumor is that the Pilot signal is coming form an Earth station in Burum, Netherlands. (minor difference from Fucino, Italy)
The work Victor Iannello, Mike Exner, Duncan Steel, Don Thompson and others (as referenced: http://tmfassociates.com/MH370Jun8.pdf ) Is narrowing in on the rumor that the EAFC was incorrectly programmed as to the Lat/Lon location for the Perth ground station. A positive (Northern Lat) for Perth results in roughly 30% reduction in the sat-Perth correction.
There was also a belief that the last radar blips established the speed and altitude of the plane at 8:22UT = low (2900ft) and slow (?)... But, my review of the radar blips indicates a much higher speed (~ 500kts ground speed) and altitude (over 35000ft to have been visible on radar at that distance). –
Recent statements from Inmarsat and other participants in the official search effort seem to support the idea that the new search area will be along the same arc, but further South and West, closer to the initial Inmarsat projected paths.
One previously released image "Example Southern Tracks" shows a red line for a "Constant 400 Knts Track", and a yellow line for a "Constant 450 knts Track".
The speeds in the BFO analysis in my paper are not directly constrained by the fuel usage. I have taken a maximum speed of 500kt for the first leg to the 18:29UT ping arc, if only because the original speed was 470kt, but the BFO data does not allow any faster speed that 330kt for later legs even for the fits to the four BFO values that take it much further South. Unless the BFO data has been changed a large amount by later analysis, the higher speed tracks are not consistent with the data.
The BFO data is a tough constraint on possible tracks, at least for simple track models.