Malaysian Airlines MH370 contact lost
Join Date: May 2003
Location: Cote d'Azur
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
Statistical Search Methods
Has any information been published on which, if any, mathematical/statistical models have been deployed in the MH370 search?
Bayesian methods were mentioned back in this post but only in relation to AF447.
Bayesian methods were mentioned back in this post but only in relation to AF447.
Join Date: Dec 2001
Location: England
Posts: 1,389
Likes: 0
Received 0 Likes
on
0 Posts
How do we know that an emergency descent was not initiated, making the groundspeed lower and the range much less? The latest ATSB report doesn't appear to discuss that possibility?
Edit: The assumptions are on page 21.
Join Date: Jul 2005
Location: btw SAMAR and TOSPA
Posts: 566
Likes: 0
Received 0 Likes
on
0 Posts
A very good and comprehensive report. It shows how professional the working groups are trying to resolve the problems.
The only thing I am missing is:
in which AP lateral mode (mag track? mag hdg?) would the 777 have flown, if LNAV along waypoints was ruled out?
A "direct to" is unlikely as the curved path does not seem to correspond to a great circle path.
The only thing I am missing is:
in which AP lateral mode (mag track? mag hdg?) would the 777 have flown, if LNAV along waypoints was ruled out?
A "direct to" is unlikely as the curved path does not seem to correspond to a great circle path.
Join Date: Jun 2009
Location: Canada
Posts: 464
Likes: 0
Received 0 Likes
on
0 Posts
See page 23 of: http://www.atsb.gov.au/media/4911984...370-report.pdf
Keeping Danny in Sandwiches
Join Date: May 1999
Location: UK
Age: 76
Posts: 1,294
Likes: 0
Received 0 Likes
on
0 Posts
Three Miles
I think they have jumped to a conclusion that isn't justified. There is no reason why the aircraft couldn't have flown using LNAV to a waypoint or destination miles beyond its endurance. My theory stated many times is Wilkins Runway as destination and that is being backed up by the evidence in the report.
The only thing I am missing is:
in which AP lateral mode (mag track? mag hdg?) would the 777 have flown, if LNAV along waypoints was ruled out?
in which AP lateral mode (mag track? mag hdg?) would the 777 have flown, if LNAV along waypoints was ruled out?
Join Date: Oct 2007
Location: France
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
Very interesting stuff!
After a quick reading, a probable stupid question: at the last page (58), table 6:
Downlink Doppler: -79.5 -75.1 -70.7 Hz Satellite movement, which I understand as the Doppler of the down link (the DeltaFdown variable of page 56), so between 3F-1 and Perth
Why does this value change with the latitude of the aircraft?
Does this value include the error for the faulty compensation from the aircraft because the satellite is assumed to be in another location it actually is?
After a quick reading, a probable stupid question: at the last page (58), table 6:
Downlink Doppler: -79.5 -75.1 -70.7 Hz Satellite movement, which I understand as the Doppler of the down link (the DeltaFdown variable of page 56), so between 3F-1 and Perth
Why does this value change with the latitude of the aircraft?
Does this value include the error for the faulty compensation from the aircraft because the satellite is assumed to be in another location it actually is?
Join Date: Jun 2001
Location: Rockytop, Tennessee, USA
Posts: 5,898
Likes: 0
Received 1 Like
on
1 Post
From page 34 of the ATSB report just released:
Once again, expensive assets redirected on what seem to be very speculative assumptions. Unless, of course, there is significant evidence that has not been made public.
Here's a New York Times article with an overview of the ATSB search area report:
http://www.nytimes.com/2014/06/27/wo...light-370.html
This discussion of possible MH370 waypoint and airway routing is on pages 36-37 of the ATSB report:
End of flight scenario
Note: Given the imprecise nature of the SATCOM data, it was necessary to make some assumptions regarding pilot control inputs in order to define a search area of a practical size. These assumptions were only made for the purposes of defining a search area and there is no suggestion that the investigation authority will make similar assumptions.
The limited evidence available for MH370 was compared with the accident classes listed previously.
In the case of MH370, there were multiple redundant communications systems fitted to the aircraft (3 x VHF radios, 2 x HF radios, SATCOM system, 2 x ATC transponders). However, no radio communications were received from the aircraft after 1719.29, 7 hours prior to the last SATCOM handshake at 00:19. Analysis of the SATCOM data also showed that there were probably no large changes to the aircraft’s track after approximately 1915, about 5 hours prior to the last SATCOM handshake.
Given these observations, the final stages of the unresponsive crew/ hypoxia event type appeared to best fit the available evidence for the final period of MH370’s flight when it was heading in a generally southerly direction:
loss of radio communications
long period without any en route manoeuvring of the aircraft
a steadily maintained cruise altitude
fuel exhaustion and descent
This suggested that, for MH370, it was possible that after a long period of flight under autopilot control, fuel exhaustion would occur followed by a loss of control without any control inputs.
Note: This suggestion is made for the sole purpose of assisting to define a search area. The determination of the actual factors involved in the loss of MH370 are the responsibility of the accident investigation authority and not the SSWG.
Note: Given the imprecise nature of the SATCOM data, it was necessary to make some assumptions regarding pilot control inputs in order to define a search area of a practical size. These assumptions were only made for the purposes of defining a search area and there is no suggestion that the investigation authority will make similar assumptions.
The limited evidence available for MH370 was compared with the accident classes listed previously.
In the case of MH370, there were multiple redundant communications systems fitted to the aircraft (3 x VHF radios, 2 x HF radios, SATCOM system, 2 x ATC transponders). However, no radio communications were received from the aircraft after 1719.29, 7 hours prior to the last SATCOM handshake at 00:19. Analysis of the SATCOM data also showed that there were probably no large changes to the aircraft’s track after approximately 1915, about 5 hours prior to the last SATCOM handshake.
Given these observations, the final stages of the unresponsive crew/ hypoxia event type appeared to best fit the available evidence for the final period of MH370’s flight when it was heading in a generally southerly direction:
loss of radio communications
long period without any en route manoeuvring of the aircraft
a steadily maintained cruise altitude
fuel exhaustion and descent
This suggested that, for MH370, it was possible that after a long period of flight under autopilot control, fuel exhaustion would occur followed by a loss of control without any control inputs.
Note: This suggestion is made for the sole purpose of assisting to define a search area. The determination of the actual factors involved in the loss of MH370 are the responsibility of the accident investigation authority and not the SSWG.
Here's a New York Times article with an overview of the ATSB search area report:
http://www.nytimes.com/2014/06/27/wo...light-370.html
This discussion of possible MH370 waypoint and airway routing is on pages 36-37 of the ATSB report:
MH370
Radar data showed that after take-off MH370 tracked in accordance with its flight-planned route to waypoint IGARI and then turned right towards waypoint BITOD. Secondary radar data was lost shortly afterwards. Primary radar data then showed that MH370 deviated from its flight-planned route.
Primary radar data showed that the aircraft tracked along the Malacca Strait. During this time the aircraft passed close to waypoints VAMPI, MEKAR, NILAM and possibly IGOGU along a section of airway N571.
Southern air routes/waypoints
Air routes and waypoints were then examined to see if there was any correlation with the possible southern tracks for MH370 obtained from the analysis of the SATCOM data. Relevant southern air routes that MH370 may have intersected/traversed were N509, N640, L894 and M641. Waypoints associated with these air routes were also considered as possible points on the MH370 flight path.
N509 ELATI 0200.0S 08957.7E
PORT HEDLAND
N640 TRIVANDRUM
BIKOK 0817.0N 07836.0E
COLOMBO
LEARMONTH
MOUNT HOPE
ADELAIDE
L894 KITAL 2003.0N 06018.0E
MALE
SUNAN 0028.7S 07800.0E
DADAR 0200.0S 07927.1E
PERTH
M641 MADURAI
BIKOK 0817.0N 07836.0E
COLOMBO
COCOS IS
The waypoints at MUTMI and RUNUT were also considered as possible points that MH370 may have crossed. However ground tracks through these points did not correlate well with the most favoured paths generated through the analysis of the BFO and BTO data.
Air routes/ waypoints summary
Although waypoints and air routes were examined and compared to possible tracks derived from analysis of the SATCOM data, there was insufficient evidence to positively determine whether MH370 intersected any waypoints associated with published air routes in the Southern Indian Ocean.
Radar data showed that after take-off MH370 tracked in accordance with its flight-planned route to waypoint IGARI and then turned right towards waypoint BITOD. Secondary radar data was lost shortly afterwards. Primary radar data then showed that MH370 deviated from its flight-planned route.
Primary radar data showed that the aircraft tracked along the Malacca Strait. During this time the aircraft passed close to waypoints VAMPI, MEKAR, NILAM and possibly IGOGU along a section of airway N571.
Southern air routes/waypoints
Air routes and waypoints were then examined to see if there was any correlation with the possible southern tracks for MH370 obtained from the analysis of the SATCOM data. Relevant southern air routes that MH370 may have intersected/traversed were N509, N640, L894 and M641. Waypoints associated with these air routes were also considered as possible points on the MH370 flight path.
N509 ELATI 0200.0S 08957.7E
PORT HEDLAND
N640 TRIVANDRUM
BIKOK 0817.0N 07836.0E
COLOMBO
LEARMONTH
MOUNT HOPE
ADELAIDE
L894 KITAL 2003.0N 06018.0E
MALE
SUNAN 0028.7S 07800.0E
DADAR 0200.0S 07927.1E
PERTH
M641 MADURAI
BIKOK 0817.0N 07836.0E
COLOMBO
COCOS IS
The waypoints at MUTMI and RUNUT were also considered as possible points that MH370 may have crossed. However ground tracks through these points did not correlate well with the most favoured paths generated through the analysis of the BFO and BTO data.
Air routes/ waypoints summary
Although waypoints and air routes were examined and compared to possible tracks derived from analysis of the SATCOM data, there was insufficient evidence to positively determine whether MH370 intersected any waypoints associated with published air routes in the Southern Indian Ocean.
Last edited by Airbubba; 26th Jun 2014 at 17:59.
Join Date: Jun 2009
Location: Auckland
Age: 81
Posts: 191
Likes: 0
Received 0 Likes
on
0 Posts
http://www.nytimes.com/2014/06/27/wo...-370.html?_r=0
If Zahari's aim was to hide the plane forever, to punish the Malaysian government or whatever, he might have seen the prospect of his own death as collateral damage. During times of war, men sometimes do things even when their death is inevitable; we regard them as brave warriors. One clinical psychologist talking about his experience of typical suicidal patients is irrelevant, there is nothing "usual" about this case - it is weird, whatever the "final" explanation is presented to us.
Advocates of the hypoxia theory argue that pilot suicide cases tend to involve pilots who crashed their planes suddenly, not after hours of flight. A clinical psychologist advising the investigation has been very skeptical of the suicide theory, saying it would be highly unusual for a suicidal person to proceed with such a deadly plan over many hours, investigators said.
Join Date: Oct 2007
Location: France
Posts: 136
Likes: 0
Received 0 Likes
on
0 Posts
Gysbreght: about the deltaFdown.
In my satellite model (which happens to differ slightly from the table 4 page 56 (0.5 to 1.5 km)), if I use a 4GHz value for the frequency, I have (at 17:05) a -82.7 BFO from the speed of the sat relative to "Perth" GES (mine is -31.80 115.89). Relative speed: ~6.2m/s.
I have a -71.4 value at 17:27.
To have -71,4 at 17:05, I have to use 3.45GHz for the downlink frequency.
All this with a very simple model and using a spherical Earth.
What is sure, IMHO, is that the aircraft have nothing to do with that [part of] BFO.
In my satellite model (which happens to differ slightly from the table 4 page 56 (0.5 to 1.5 km)), if I use a 4GHz value for the frequency, I have (at 17:05) a -82.7 BFO from the speed of the sat relative to "Perth" GES (mine is -31.80 115.89). Relative speed: ~6.2m/s.
I have a -71.4 value at 17:27.
To have -71,4 at 17:05, I have to use 3.45GHz for the downlink frequency.
All this with a very simple model and using a spherical Earth.
What is sure, IMHO, is that the aircraft have nothing to do with that [part of] BFO.
Join Date: Jul 2013
Location: uk
Posts: 180
Likes: 0
Received 0 Likes
on
0 Posts
370 latest search area
so 65000 sq m to be covered. presume they will use at least two sets of wreck location equipment, starting from opposite sides or ends of the search area and finishing in the middle. using only one might result in the worst case scenario of not finding the aircraft until the very end or of course the opposite happy outcome of finding it on day one.
"If Zahari's aim was to hide the plane forever, to punish the Malaysian government or whatever, he might have seen the prospect of his own death as collateral damage. During times of war, men sometimes do things even when their death is inevitable; we regard them as brave warriors. One clinical psychologist talking about his experience of typical suicidal patients is irrelevant, there is nothing "usual" about this case - it is weird, whatever the "final" explanation is presented to us."
but he wouldn't have to kill himself nor anyone else, landing on one of australian islands would do a job
when we are at that, have they searched the northern areas at all?
but he wouldn't have to kill himself nor anyone else, landing on one of australian islands would do a job
when we are at that, have they searched the northern areas at all?
Join Date: Apr 2014
Location: Australia
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
Would they not have made a radio call if the above were true. It appears the aircraft flew normally and was not damaged or in distress.
These highly ranked officials coming out and making claims about what happened is really poor showing in my mind. They stuffed up the sonar pings and they were so Gung-ho confident prior to that. It appears they haven't even confirmed the source of the so called false pings. Thus were they really false? when prior they were extremely confident.
Deputy PM now claims the plane was likely on auto pilot. He could be right but that's not a proven fact. What if they used GPS navigation? I think the officials should only be reporting facts, but I guess they have few to go on so they are filling in the gaps, however given the errors they have already made, it's difficult to have confidence.
Join Date: Apr 2014
Location: Australia
Age: 76
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
HeyIts007
They are merely assumptions intended to narrow down the search area. The report is quite clear on this pointing out that the assumptions have no bearing on the accident investigation.
These highly ranked officials coming out and making claims about what happened is really poor showing in my mind.
Join Date: Apr 2014
Location: Australia
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
They are merely assumptions intended to narrow down the search area. The report is quite clear on this pointing out that the assumptions have no bearing on the accident investigation.
Of course they need to make assumptions
And if they had not made, used and explained their assumptions we'd have had another 6 months of incessant whining about "why are they concealing the details?" or "how can they do this without giving me, personally, every detail of their actions and decision making along with hourly updates?"
I don't own this space under my name. I should have leased it while I still could
Hey, it is apparent that your reading differs from ours.
Investigators are those that will determine the possible or probable causes. There is no certainty that they will discover the certain cause.
The search organization's only link with the investigators is to deliver evidential material to them. Assumptions are purely there to create a viable search plan. Those assumptions may be modified in time.
Now politicians are different again. They are generalists, and while experts at saying one thing and meaning something else, the are not technicians. They may not appreciate or reflect the nuances in the experts report.
For those that are aware, the report is a model or clarity and caution.
Investigators are those that will determine the possible or probable causes. There is no certainty that they will discover the certain cause.
The search organization's only link with the investigators is to deliver evidential material to them. Assumptions are purely there to create a viable search plan. Those assumptions may be modified in time.
Now politicians are different again. They are generalists, and while experts at saying one thing and meaning something else, the are not technicians. They may not appreciate or reflect the nuances in the experts report.
For those that are aware, the report is a model or clarity and caution.
Join Date: Dec 2013
Location: Paso Robles
Posts: 261
Likes: 0
Received 0 Likes
on
0 Posts
using only one might result in the worst case scenario of not finding the aircraft until the very end or of course the opposite happy outcome of finding it on day one.
If you have just one you start most likely in the most probable place - say the center of the yellow rectangle and then proceed in circular/rectangular motion around it.
Join Date: May 2010
Location: EDDS
Age: 54
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
assumption: flight ends with spiral
From the report
http://www.atsb.gov.au/media/4911984...370-report.pdf
"- loss of radio communications
- long period without any en route manoeuvring of the aircraft
- a steadily maintained cruise altitude
- fuel exhaustion and descent
This suggested that, for MH370, it was possible that after a long period of flight under autopilot
control, fuel exhaustion would occur followed by a loss of control without any control inputs.
Note: This suggestion is made for the sole purpose of assisting to define a search area.
The determination of the actual factors involved in the loss of MH370 are the responsibility
of the accident investigation authority and not the SSWG
.
Also allowing for the fact that a maximum glide distance of 100+ NM would result in an
impractically large search area, the search team considered that it was reasonable to assume that
there were no control inputs following the flame-out of the second engine. Accordingly the aircraft
would descend and, as there would be some asymmetry due to uneven engine thrust/drag or
external forces e.g. wind, the descent would develop into a spiral."
I still haven't got that. Maybe because I'm just a CPL/MEPL, but why should fuel exhaustion under autopilot end in a spiral dive? Is the auto pilot on the B777 completely disconnecting on fuel starvation? I'd guess the Ram Generator would deliver the power for autopilot + controls, the envelope protection of the AP would prevent a stall and the AP would maintain the track. That would place the center of the search area about 100 NM forward in flight direction.
http://www.atsb.gov.au/media/4911984...370-report.pdf
"- loss of radio communications
- long period without any en route manoeuvring of the aircraft
- a steadily maintained cruise altitude
- fuel exhaustion and descent
This suggested that, for MH370, it was possible that after a long period of flight under autopilot
control, fuel exhaustion would occur followed by a loss of control without any control inputs.
Note: This suggestion is made for the sole purpose of assisting to define a search area.
The determination of the actual factors involved in the loss of MH370 are the responsibility
of the accident investigation authority and not the SSWG
.
Also allowing for the fact that a maximum glide distance of 100+ NM would result in an
impractically large search area, the search team considered that it was reasonable to assume that
there were no control inputs following the flame-out of the second engine. Accordingly the aircraft
would descend and, as there would be some asymmetry due to uneven engine thrust/drag or
external forces e.g. wind, the descent would develop into a spiral."
I still haven't got that. Maybe because I'm just a CPL/MEPL, but why should fuel exhaustion under autopilot end in a spiral dive? Is the auto pilot on the B777 completely disconnecting on fuel starvation? I'd guess the Ram Generator would deliver the power for autopilot + controls, the envelope protection of the AP would prevent a stall and the AP would maintain the track. That would place the center of the search area about 100 NM forward in flight direction.
Join Date: Aug 2007
Location: Dublin
Posts: 987
Likes: 0
Received 0 Likes
on
0 Posts
An airline that has shown the world how badly it was caught out with such a a long list of outstanding safety recommendations that it had failed to implement must be very frustrating for investigators.
Keeping Danny in Sandwiches
Join Date: May 1999
Location: UK
Age: 76
Posts: 1,294
Likes: 0
Received 0 Likes
on
0 Posts
I'd guess the Ram Generator would deliver the power for autopilot + controls, the envelope protection of the AP would prevent a stall and the AP would maintain the track. That would place the center of the search area about 100 NM forward in flight direction.