AF 447 Search to resume
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I know we’ve analyzed this many, many times before, but most of us have probably gone to sleep or not, thinking about how that tailfin came off forward.
Well, I think it didn’t, in the normal sense, following on from Machinebirds break-up analysis, i.e. around the doors which I tend to agree with.
I would suggest that the fuselage broke, somewhere around the rear doors and with the aid of the horizontal stabiliser providing lift, that section immediately rotated rearwards, breaking the rudder rod 39g filling the fin with water under pressure, which the mountings couldn’t withstand.
We’ve seen powerboats do the same thing.
What would then happen to the rest of the aircraft would depend on whether there was significant thrust at the time, i.e. if the tail hit and broke before the rest made contact.
I think there are many similarities here, in terms of final arrival, with the Tripoli accident, although go-around power is probably not in the equation.
As an aside, I’d just like to praise the bravery of French sub-marimen, I suspect they are the only force of men that set to sea in nuclear powered submarines knowing that if anything happens their government will source a third party salvage team from anywhere in the world to rescue them. Harsh I know, but considering the French Navy operate such vessels it’s very strange that they don’t seem to have deep sea search available to assist with AF447 and I would hate to think what would happen if one of their subs went missing.
Well, I think it didn’t, in the normal sense, following on from Machinebirds break-up analysis, i.e. around the doors which I tend to agree with.
I would suggest that the fuselage broke, somewhere around the rear doors and with the aid of the horizontal stabiliser providing lift, that section immediately rotated rearwards, breaking the rudder rod 39g filling the fin with water under pressure, which the mountings couldn’t withstand.
We’ve seen powerboats do the same thing.
What would then happen to the rest of the aircraft would depend on whether there was significant thrust at the time, i.e. if the tail hit and broke before the rest made contact.
I think there are many similarities here, in terms of final arrival, with the Tripoli accident, although go-around power is probably not in the equation.
As an aside, I’d just like to praise the bravery of French sub-marimen, I suspect they are the only force of men that set to sea in nuclear powered submarines knowing that if anything happens their government will source a third party salvage team from anywhere in the world to rescue them. Harsh I know, but considering the French Navy operate such vessels it’s very strange that they don’t seem to have deep sea search available to assist with AF447 and I would hate to think what would happen if one of their subs went missing.
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Content Analysis
Since June of 2009 there have been more than 4555 posts to the two AF447 threads at PPRuNe and, as of October 25, 2010, these discussion threads have received 2,772,948 page views. Many contributors are highly qualified scientists, engineers, aircraft designers, meteorologists, pilots, and mariners from the international community interested in both WHY the upset occurred and WHERE the wreckage along with the cockpit voice recorder (CVR) and the flight data recorder (FDR) might be found.
By way of academic experiment, I am hoping to analyze these posts using a word association and relevance algorithm to see which ideas might percolate to the top of a list of possible causes and possible search locations. To this end, I have organized the 4555 posts into several formats: .xls, .txt, .pdf, .tab, and .fp7 (FileMaker database). Data fields for each record include Date and Time, Submitter's Name, Post Title (if present), Thread Page, PPRuNe Message Number, and the Message itself. The text document in .pdf format is 1044 A4/Letter pages of 10-point Times-Roman (4.5MB) -- it's no wonder that many have prefaced their recent comments at PPRuNe with "not having reviewed all the prior posts, I'm asking if..."
I figure to do several passes through the data, first to categorize the submissions by their overall relevance to the event (tossing one-liners with no substance) and to group the postings into content-specific areas (upset vs. search, for example). Then to group them into further non-exclusive technical categories such as, for the upset: ACARS, aerodynamics, meterology, instrumentation, etc.). I could use some help developing appropriate categories and sorting (human input) before letting the computer look for word associations -- posts for example where the words ACARS and autopilot and stall and radar might occur concurrently in the text... It might be that this computer analysis is useful; much research is currently being done by outfits like Google and Microsoft to develop ways to look at data relevance. It might also be that human experts and many eyes are the only answer.
So I'd like to call for volunteers who can help me organize the categories and "weights" for this experiment before I slog through a thousand pages.
Drop me a note by PM if you are interested or have ideas. Might be an interesting project/paper for a graduate student.
I'll keep you posted.
GB
By way of academic experiment, I am hoping to analyze these posts using a word association and relevance algorithm to see which ideas might percolate to the top of a list of possible causes and possible search locations. To this end, I have organized the 4555 posts into several formats: .xls, .txt, .pdf, .tab, and .fp7 (FileMaker database). Data fields for each record include Date and Time, Submitter's Name, Post Title (if present), Thread Page, PPRuNe Message Number, and the Message itself. The text document in .pdf format is 1044 A4/Letter pages of 10-point Times-Roman (4.5MB) -- it's no wonder that many have prefaced their recent comments at PPRuNe with "not having reviewed all the prior posts, I'm asking if..."
I figure to do several passes through the data, first to categorize the submissions by their overall relevance to the event (tossing one-liners with no substance) and to group the postings into content-specific areas (upset vs. search, for example). Then to group them into further non-exclusive technical categories such as, for the upset: ACARS, aerodynamics, meterology, instrumentation, etc.). I could use some help developing appropriate categories and sorting (human input) before letting the computer look for word associations -- posts for example where the words ACARS and autopilot and stall and radar might occur concurrently in the text... It might be that this computer analysis is useful; much research is currently being done by outfits like Google and Microsoft to develop ways to look at data relevance. It might also be that human experts and many eyes are the only answer.
So I'd like to call for volunteers who can help me organize the categories and "weights" for this experiment before I slog through a thousand pages.
Drop me a note by PM if you are interested or have ideas. Might be an interesting project/paper for a graduate student.
I'll keep you posted.
GB
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GreatBear, it might be more interesting to see a serious summary of all the hypotheses with their pro and con factors. What does each hypothesis not cover with regards to apparent facts as we know them? This might lead to some fine tuning leading to some small set of consensus hypotheses to further discuss. (Ideally this discussion board would have a way to keep the running status of this data up to date and easily available.)
Another analysis would be to take a listing of all the back-tracks and see if some meta-analysis of them might provide an even better placement, or at least provide a better estimate of probable location.
Finally it might be interesting for someone with time on their hands to discuss why various "conspiracy theories" that have floated through here are silly.
For example, isn't it more damaging to all parties concerned, manufacturer, operator, owners, and investigators if they fail to fill in all the blanks by either finding the recorders (and getting lucky that the data needed really is there) or finding a convincing reason for not being able to find the recorders.
(I'm mumbling here - are there any suitable planes that have experienced too many cycles that could be chopped up into various size pieces and sunk so we can see how these composite materials sink in that area of the ocean? If they go down slow enough they could be way way off where people expect them. So they may need to go over the areas already covered looking for objects on a finer scale. Involve some universities in the project and call it a fine scale oceanographic survey as well as a search. The research results might provide some slight offset to the expenses.)
{^_^}
Another analysis would be to take a listing of all the back-tracks and see if some meta-analysis of them might provide an even better placement, or at least provide a better estimate of probable location.
Finally it might be interesting for someone with time on their hands to discuss why various "conspiracy theories" that have floated through here are silly.
For example, isn't it more damaging to all parties concerned, manufacturer, operator, owners, and investigators if they fail to fill in all the blanks by either finding the recorders (and getting lucky that the data needed really is there) or finding a convincing reason for not being able to find the recorders.
(I'm mumbling here - are there any suitable planes that have experienced too many cycles that could be chopped up into various size pieces and sunk so we can see how these composite materials sink in that area of the ocean? If they go down slow enough they could be way way off where people expect them. So they may need to go over the areas already covered looking for objects on a finer scale. Involve some universities in the project and call it a fine scale oceanographic survey as well as a search. The research results might provide some slight offset to the expenses.)
{^_^}
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(We may also drop an engine somewhere between the LKP and the pollution spot and and see if we don't find as well both of the GE we were looking for ...) 
Last edited by CONF iture; 28th Oct 2010 at 02:52.
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GB - Great idea. I have often thought that if we could meld the information provided and discussed in all these many posts, then we could most likely arrive at a probable cause which could be defended. Will be interesting to see how all this developes. Thanks for the undertaking.
GreatBear, JD-EE,
I like both of your approaches !
It might be worthwhile to do both. And then compare the results.
Going only for GreatBear's approach is very interesting all by itself even just to see if it is doable at all, yet it will be difficult to evaluate the result.
In order to draw a conclusion about the suitability finally you will need a way of validation.
And that could be exactly the opposite aaproach which is based on pro's and con's.
I like both of your approaches !
It might be worthwhile to do both. And then compare the results.
Going only for GreatBear's approach is very interesting all by itself even just to see if it is doable at all, yet it will be difficult to evaluate the result.
In order to draw a conclusion about the suitability finally you will need a way of validation.
And that could be exactly the opposite aaproach which is based on pro's and con's.
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With great respect,
I think it is an excellent idea. It is not unlike a proposal airfoilmod made with respect to the first several thousand posts on BEA038. His stopped short of "distillation", "consolidation", or even "edit", however.
Let's not forget that virtually all accidents can be explained in extremely simple terms; the chain may be complex, but the potentiation and linkages are numbingly apparent after all. For all the diffident complaints of "non-expert", and thereby "annoying" content here, let me suggest to all of us that the "expert" welcomes a simplistic query. It is at the very least a way to find new ways to make understood some "perceptually complex" concepts; in doing so, likely as not, the "professionals" find even better ways to communicate amongst themselves.
Generally speaking (generally!), it is those who identify the "stupid question" who are on the South side of those in the field who have institutional wisdom.
Think "Interdisciplinary": answers avoid the hyper focused brain, it is a fact.
bear
I think it is an excellent idea. It is not unlike a proposal airfoilmod made with respect to the first several thousand posts on BEA038. His stopped short of "distillation", "consolidation", or even "edit", however.
Let's not forget that virtually all accidents can be explained in extremely simple terms; the chain may be complex, but the potentiation and linkages are numbingly apparent after all. For all the diffident complaints of "non-expert", and thereby "annoying" content here, let me suggest to all of us that the "expert" welcomes a simplistic query. It is at the very least a way to find new ways to make understood some "perceptually complex" concepts; in doing so, likely as not, the "professionals" find even better ways to communicate amongst themselves.
Generally speaking (generally!), it is those who identify the "stupid question" who are on the South side of those in the field who have institutional wisdom.
Think "Interdisciplinary": answers avoid the hyper focused brain, it is a fact.
bear
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Bearfoil, at the risk of insulting I must say I have noticed your hyperfocus over the months here.
I note that I have changed my picture of what MIGHT have happened rather dramatically twice since I joined this system. And the picture I have now is still incomplete and leaves enough details unanswered I've decided not to push it very hard.
(Dryly I note that virtually none of the proposals show how the plane ended up where the searchers have not yet scoured the ocean bottom AND the surviving pieces show their particular breakage and stress patterns. Um, I also note nobody has done any computerized stress analysis to explain something as "small" as the fracture pattern in the vertical stabilizer's mountings. Instead we ALL make conjectures about it. The closest I've seen to modeling it is my crumby observation of what paper torn out of a three ring binder looks like for varying orientations of the tearing forces.)
I'm data driven. Feed me. Please.
{o.o}
I note that I have changed my picture of what MIGHT have happened rather dramatically twice since I joined this system. And the picture I have now is still incomplete and leaves enough details unanswered I've decided not to push it very hard.
(Dryly I note that virtually none of the proposals show how the plane ended up where the searchers have not yet scoured the ocean bottom AND the surviving pieces show their particular breakage and stress patterns. Um, I also note nobody has done any computerized stress analysis to explain something as "small" as the fracture pattern in the vertical stabilizer's mountings. Instead we ALL make conjectures about it. The closest I've seen to modeling it is my crumby observation of what paper torn out of a three ring binder looks like for varying orientations of the tearing forces.)
I'm data driven. Feed me. Please.
{o.o}
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little mistaks are possible
"Later, a ranch hand reported seeing Fossett's aircraft less than 20 miles from the Hilton ranch's airport, at around 11 a.m. By then, Fossett would have had less than two hours of fuel left, so his aircraft would have gone down within the two-hour range."
GreatBear, did you remember this search over more than a year, with the search area over 10,000 square miles and thousands of words in hundreds of blogs...?
one year later the balanca lays outside the search area because the ranch hand perhaps did not change the time in his mobile to the summertime and he saw the plane around 10 a.m. and not at 11 a.m. and over all the year the search area was a little wrong.
did you think that even one word in only one of the hundred blogs was helpfully to identifier this little mistake of one hour? I d´not think so
sincerly grity
GreatBear, did you remember this search over more than a year, with the search area over 10,000 square miles and thousands of words in hundreds of blogs...?
one year later the balanca lays outside the search area because the ranch hand perhaps did not change the time in his mobile to the summertime and he saw the plane around 10 a.m. and not at 11 a.m. and over all the year the search area was a little wrong.
did you think that even one word in only one of the hundred blogs was helpfully to identifier this little mistake of one hour? I d´not think so
sincerly grity
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JD-EE
In your response you note an attempt at "modelling" via a paper model. It was an original and valid venture. Have you forgotten how some of us modelled the VS in an attempt to better understand how it may have behaved had it fallen from some distance?
It is beyond logic to demand "data" exclusively here, the discussion would have disappeared months ago with BEA's first thirty day report. Data as has been released is sparse, (transparency from the authority is lacking?), much if not all of this interesting give and take is flowing from "what-ifs" and possibilities based on accident history and basic physics as offered by intelligent and engaged folks.
Any engineering format will be challenged by nature and circumstance. Nature brooks no fools nor haphazard construction/inattention. As I have said, I believe accidents end up being numbingly obvious; the surprise is "ours", some unplanned for misstep or failing.
In accident investigation, "data" is suggestive, instructive. Establishing the chain is the challenge.
A long ago accident involved a "DC" propellor a/c that caught fire while airborne; it crashed. Looking for "data" suggested that a gasoline "supply" to the Cabin Heater was intended to vent into the airstream, but in rare aerodynamic aspect, the liquid fuel dumped directly into the heater's skin mounted intake. More recent crashes involve somewhat more involved explanation, but I remain unconvinced that ultimate answers are any more difficult to understand, post investigation.
It is redundant for you to demand "data" when it is sequestered by the authority, and for demonstrated reasons. Investigation is traditionally sequestered, a device that no longer serves the public at large, imo.
Corporate politics are no different from Government policies. In fact, they generally instruct the body politic in a leading manner. Conjecture here is overdone by default; "what-if" is part and parcel of the group discussion, based on data at hand.
Snide judgments of others' questions, and the bemoaning of "unproffessional" comment is not adding to progress here. The obligation to provide you with data is not mine, nor is it incumbent on others. For me, I read everything with an open mind.
Prior expectation emanating from a narrow background is the obstacle, not the answer. For me, I have been well-paid in the past working in accident investigation and reporting (writing), my curiosity with each post is served by its presence merely, I do not find anyone's contribution worthy of prior dismissal. Patience is meant to be experienced when thin, it is what causes thickening when challenged in future episodes. IMO.
best,
bear
In your response you note an attempt at "modelling" via a paper model. It was an original and valid venture. Have you forgotten how some of us modelled the VS in an attempt to better understand how it may have behaved had it fallen from some distance?
It is beyond logic to demand "data" exclusively here, the discussion would have disappeared months ago with BEA's first thirty day report. Data as has been released is sparse, (transparency from the authority is lacking?), much if not all of this interesting give and take is flowing from "what-ifs" and possibilities based on accident history and basic physics as offered by intelligent and engaged folks.
Any engineering format will be challenged by nature and circumstance. Nature brooks no fools nor haphazard construction/inattention. As I have said, I believe accidents end up being numbingly obvious; the surprise is "ours", some unplanned for misstep or failing.
In accident investigation, "data" is suggestive, instructive. Establishing the chain is the challenge.
A long ago accident involved a "DC" propellor a/c that caught fire while airborne; it crashed. Looking for "data" suggested that a gasoline "supply" to the Cabin Heater was intended to vent into the airstream, but in rare aerodynamic aspect, the liquid fuel dumped directly into the heater's skin mounted intake. More recent crashes involve somewhat more involved explanation, but I remain unconvinced that ultimate answers are any more difficult to understand, post investigation.
It is redundant for you to demand "data" when it is sequestered by the authority, and for demonstrated reasons. Investigation is traditionally sequestered, a device that no longer serves the public at large, imo.
Corporate politics are no different from Government policies. In fact, they generally instruct the body politic in a leading manner. Conjecture here is overdone by default; "what-if" is part and parcel of the group discussion, based on data at hand.
Snide judgments of others' questions, and the bemoaning of "unproffessional" comment is not adding to progress here. The obligation to provide you with data is not mine, nor is it incumbent on others. For me, I read everything with an open mind.
Prior expectation emanating from a narrow background is the obstacle, not the answer. For me, I have been well-paid in the past working in accident investigation and reporting (writing), my curiosity with each post is served by its presence merely, I do not find anyone's contribution worthy of prior dismissal. Patience is meant to be experienced when thin, it is what causes thickening when challenged in future episodes. IMO.
best,
bear
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If, for example, one was new to this discussion and has read only the last few hundred posts, one might venture the following: The upset most likely occurred with the auto-pilot's dropout, (in fact, upset may have caused the drop) otherwise the pilots might have disconnected prior. Involuntary drop would suggest surprise. Surprise is not welcome in a pilot's world, it like as not causes non innovative thinking, or at least a stress level that could foreclose solutions in even the highly trained man. Here is a wide body twin, upset, at great altitude, in the dark. The weather is demonstrably crapola, the panel is lighting up, (as it is intended to), with warnings, each one demanding the requisite action. The immediate call is to regain aerodynamic flight, regain stability. One would let drop all consideration of navigation and communication in the interest of flight.(Aviate, Navigate, Communicate). The lack of mayday or any position report here is highly suggestive of disabled comm, or a work load that commands exclusion of comm, or nav. If in a cell, one attempts to gain manouvering velocity, and control, hang the flight's 'direction'. Perhaps the decision had been made earlier to offset to the right of the airway, a fact that would be in a pilot's recent strategy, and have an influence on the heading he chose to try to evac the cell. If he had turned right to exit the cell, and regained controllable flight, but had encountered mech issues that obviated continued twin ops shy of the 50% mark of overwater operation, he might have continued well right of the airway, attempting to "return". A turn of this sort puts him into the area of the "bifurcated" slick. This stain has a definite shape, and a suggestion therefrom of recent cause. If engine trouble, the need to turn is obvious. "South, SouthEast", is a completely understandable position to have, given what we know, without injecting too much "conjecture".
Upon destroying this posit, there are two or three others that come immediately to mind.
bear
Upon destroying this posit, there are two or three others that come immediately to mind.
bear
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Bearfoil, mm43's backtrack calculations and plots are solid data as far as source data can be found. Indications are that it may be fairly accurate as a guess, since more a priori logical places for impact have been searched and found wanting.
Losing the VS at altitude can partially explain why the plane was not out where it was expected to be found. I'm not sure about that. But I can grant it. It does not seem to explain the apparent attitude and impact vector when the plane hits the water. And a complete break up at altitude does not seem to explain some of the damage observed such as that on the crews rest facility.
I'll grant it's a valid potential to look at. But an event tree from altitude to water that avoids "and magic happens" and too many "lots of choices here that make no serious difference would be helpful. The events on the way down need to be 'dense enough' to explain why 121.5 MHz remained silent, for example.
That is one of the great unexplained mysteries of the flight. Why, as soon as the change over to the African station could not take place, didn't the crew contact a nearby aircraft on 121.5 MHz to ask them for contact help? That should be SOP, I'd think. If events happened so densely that coping with them left no time for the radio it starts to make sense. But that would mean the problems began far earlier than any of us have suggested so far.
So the best tools at present are inventing hypothetical event trees from normal flight to impact with the ocean in roughly, within a few miles, of where mm43's backtracking put it or at least into an unsearched area. (At least the engines should have gone straight down unless they did not separate from the rest of the plane AND the fuel tank bladders did not lose integrity.)
I'd suspect that is the sort of investigation BEA is struggling through at this time. With a little thinking you can easily see how many branches each second of the way down might have. At least there are rough event "checkpoints" on the way down that might be helpful, the ACARS messages and the gap in the messages come into play as points that can rule out large groups of branches in the event trees. But the problem is that we don't even know within a gross guess how the plane broke up, into many large pieces with a lot of small pieces or all small pieces.
So give some slack, presume that BEA is doing this (at least for exercise), and then start doing it ourselves somehow. When we note a hypothesis starts to break down, "file a bug report" and let people try to solve the "bug". The sad thing is that while we are motivated here many of us have day jobs, too, I suppose. (I am playing hooky right now myself.)
{^_^}
Losing the VS at altitude can partially explain why the plane was not out where it was expected to be found. I'm not sure about that. But I can grant it. It does not seem to explain the apparent attitude and impact vector when the plane hits the water. And a complete break up at altitude does not seem to explain some of the damage observed such as that on the crews rest facility.
I'll grant it's a valid potential to look at. But an event tree from altitude to water that avoids "and magic happens" and too many "lots of choices here that make no serious difference would be helpful. The events on the way down need to be 'dense enough' to explain why 121.5 MHz remained silent, for example.
That is one of the great unexplained mysteries of the flight. Why, as soon as the change over to the African station could not take place, didn't the crew contact a nearby aircraft on 121.5 MHz to ask them for contact help? That should be SOP, I'd think. If events happened so densely that coping with them left no time for the radio it starts to make sense. But that would mean the problems began far earlier than any of us have suggested so far.
So the best tools at present are inventing hypothetical event trees from normal flight to impact with the ocean in roughly, within a few miles, of where mm43's backtracking put it or at least into an unsearched area. (At least the engines should have gone straight down unless they did not separate from the rest of the plane AND the fuel tank bladders did not lose integrity.)
I'd suspect that is the sort of investigation BEA is struggling through at this time. With a little thinking you can easily see how many branches each second of the way down might have. At least there are rough event "checkpoints" on the way down that might be helpful, the ACARS messages and the gap in the messages come into play as points that can rule out large groups of branches in the event trees. But the problem is that we don't even know within a gross guess how the plane broke up, into many large pieces with a lot of small pieces or all small pieces.
So give some slack, presume that BEA is doing this (at least for exercise), and then start doing it ourselves somehow. When we note a hypothesis starts to break down, "file a bug report" and let people try to solve the "bug". The sad thing is that while we are motivated here many of us have day jobs, too, I suppose. (I am playing hooky right now myself.)
{^_^}
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Bearfoil, one more observation and then I shut up for awhile (I hope. {^_-})
As I noted the lack of communications is very troubling, at least to me. I am communications (engineering) oriented. So I tend to see it as a solution to problems at almost every level from communications between stick and elevators through communications between plane and control locations on the ground to communications between employees at ALL levels of Air France and BEA. This extends onwards to communications from them to the rest of the world.
So as soon as they could not contact their controller in Africa they should have done something about it before getting near the storm area. Two tries then hit 121.5 and bug an airborne "neighbor" within a two or three hundred miles for a relay. With my heavy communications background I am perhaps blinded to obvious reasons they might not have. But it does leave me with an additional period of apparent inactivity on the part of the pilots that I cannot explain. Nor can I explain why it seems to be glossed over in reporting and why this obvious (partial) fix to a vulnerability in the system is not being fixed. Of course, this extends the time frame of my event tree analysis. It may partially explain why NOBODY heard a peep from them when they got into their pickle. They were either VERY busy continuously or had no power for communications.
(And out over the ocean I'd "aviate", get altitude, communicate, then navigate. But that's a side point. Flight and altitude give cushion, a report to ground by one pilot as the other recovers bearings for navigation would be in order over ocean. If altitude and position are uncertain comunications could be a life saver for them and other planes. Over land with a LOT of other planes very nearby the order needs to be fly, fly in the right place at the right time, communicate for every clear reasons.)
Anyway, for my thinking the event trees start branching within tens of seconds after their last attempt to contact Africa. And I also note that I see several holes in the communications protocol. Many of them could be the communications hole AF447 fell into.
As an aside, how long does the CVR recording to backwards in history? It may be quite important to get it if the recording goes back to their last communications attempt.
{o.o}
As I noted the lack of communications is very troubling, at least to me. I am communications (engineering) oriented. So I tend to see it as a solution to problems at almost every level from communications between stick and elevators through communications between plane and control locations on the ground to communications between employees at ALL levels of Air France and BEA. This extends onwards to communications from them to the rest of the world.
So as soon as they could not contact their controller in Africa they should have done something about it before getting near the storm area. Two tries then hit 121.5 and bug an airborne "neighbor" within a two or three hundred miles for a relay. With my heavy communications background I am perhaps blinded to obvious reasons they might not have. But it does leave me with an additional period of apparent inactivity on the part of the pilots that I cannot explain. Nor can I explain why it seems to be glossed over in reporting and why this obvious (partial) fix to a vulnerability in the system is not being fixed. Of course, this extends the time frame of my event tree analysis. It may partially explain why NOBODY heard a peep from them when they got into their pickle. They were either VERY busy continuously or had no power for communications.
(And out over the ocean I'd "aviate", get altitude, communicate, then navigate. But that's a side point. Flight and altitude give cushion, a report to ground by one pilot as the other recovers bearings for navigation would be in order over ocean. If altitude and position are uncertain comunications could be a life saver for them and other planes. Over land with a LOT of other planes very nearby the order needs to be fly, fly in the right place at the right time, communicate for every clear reasons.)
Anyway, for my thinking the event trees start branching within tens of seconds after their last attempt to contact Africa. And I also note that I see several holes in the communications protocol. Many of them could be the communications hole AF447 fell into.
As an aside, how long does the CVR recording to backwards in history? It may be quite important to get it if the recording goes back to their last communications attempt.
{o.o}
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The A-330 is a recent aircraft, so two hours is the most likely (maybe the type is mentioned in the BEA reports?).
CJ
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JD-EE
Lets go back in the time machine...!
I suspect the above from post #4480 in the original AF447 thread takes us back to the time you are mentioning.
For what it is worth, I seem to remember that Dakar's time was 1 minute fast, and I suspect that the ADS-C connection was an auto connect that failed because Dakar hadn't received the flight plan. ETA TASIL was 0220z, and I wouldn't expect an HF call on 6535kHz until close to that time. Bear in mind that ATLANTICO and DAKAR don't share the same HF suite of frequencies, and if ATLANTICO had any doubts about the aircraft establishing contact with DAKAR they would have requested a confirmation of transfer back on their own frequency. In this case, we know that the AFTN comms between ATLANTICO and DAKAR was good, and in theory DAKAR would have requested the a/c position from ATLANTICO if a transfer call had not been received. All this got messed up by the "misplaced" flight plan.
So, in summary the a/c was not overdue for a report until 0220z, and DAKAR OCEANIC allowed it to continue on a virtual flight plan filed by ATLANTICO without much thought until they were later queried by ATLANTICO when questions started coming out of Paris. Remember the failed auto connect on ADS-C doesn't necessarily indicate cockpit activity or not.
As an after thought .... this is not helping in finding where the aircraft impacted with "terra oceania". Methinks that with the amount of water that has passed under the clouds, that the "pollution spot" is as good a place to start as any other.
mm43
Lets go back in the time machine...!
Once the SELCAL had checked at 0135 it appears the crew selected SELCAL watch as ATLANTICO's attempts to contact them a few seconds later went unanswered. Why ATLANTICO failed to SELCAL them is another matter. We don't even know if AF447 had selected 123.45, but no one has reported hearing them on either HF or VHF after 0135. A failed ADS-C connection at 0201 with DAKAR OCEANIC is the only evidence of cockpit activity.
For what it is worth, I seem to remember that Dakar's time was 1 minute fast, and I suspect that the ADS-C connection was an auto connect that failed because Dakar hadn't received the flight plan. ETA TASIL was 0220z, and I wouldn't expect an HF call on 6535kHz until close to that time. Bear in mind that ATLANTICO and DAKAR don't share the same HF suite of frequencies, and if ATLANTICO had any doubts about the aircraft establishing contact with DAKAR they would have requested a confirmation of transfer back on their own frequency. In this case, we know that the AFTN comms between ATLANTICO and DAKAR was good, and in theory DAKAR would have requested the a/c position from ATLANTICO if a transfer call had not been received. All this got messed up by the "misplaced" flight plan.
So, in summary the a/c was not overdue for a report until 0220z, and DAKAR OCEANIC allowed it to continue on a virtual flight plan filed by ATLANTICO without much thought until they were later queried by ATLANTICO when questions started coming out of Paris. Remember the failed auto connect on ADS-C doesn't necessarily indicate cockpit activity or not.
As an after thought .... this is not helping in finding where the aircraft impacted with "terra oceania". Methinks that with the amount of water that has passed under the clouds, that the "pollution spot" is as good a place to start as any other.
mm43