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AF 447 Search to resume

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AF 447 Search to resume

Old 29th Nov 2010, 18:35
  #2501 (permalink)  
bearfoil
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I am lost when it comes to currents and winds affecting the bodies. I am not even sure if the indexing of each victim is by date found, or some extrapolation. It does seem to me that the first body found would be closest to the wreck, and all current analysis must start the "backcasting" there, on that spot? Whatever distance separated the victims at water entry was simply expanded, and as Slat11 has said, a funnel shape should point to the impact point. That is the simplest and most direct process, imo.

The pollution spot, with its "forks" seems to be explained best (HN39?) in that the point may be impact, and as the fuel sank with the wreckage, it floated in an ever increasing fan up to the surface. The impact loss of fuel would have started drifting right away, and the sinking fuel would have remained somewhat "localized?" If the HS and Tail Tank drifted in another direction, but provided fuel for the upward flow, would not the bulk of the surface fuel be closest to the impact point? (The bottom of the inverted "V", left). This is simplistic, naturally.

I want to continue to remind us that a very large body of evidence has not been made public. The families, to include the Brazilians, have 'partnered' with the BEA now. I don't know how the French do it, but without subpoena, or pending Court action, an American group might be told to "Just Wait for The Final Report!!"

With the Families in the 'group investigating', and BEA's seeming unwillingness to make public their plans, one suspects that BEA were......"encouraged". Court records in the US are almost always "Of Record", "Open".

bear
 
Old 29th Nov 2010, 19:52
  #2502 (permalink)  
 
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slats11, perhaps mm43 has the data, but I have not seen it. The data being:

a.) the daily boundaries of the aerial search grids flown after June 7.
b.) the day, time, and location of wreckage and/or bodies as initially spotted daily in the searches flown in a.).
c.) the correlation between b.) and the day, time, and location of the retrieval of the spotted wreckage and bodies by surface vessels.

c.) ought give you some approximation of the current and windage at least during the period between events b and c.

takata was hypothesizing early on that the flight deviated right, and possibly had reversed course and was headed toward St. Peter and St. Paul when it crashed.

There are a lot of variables that might explain the Brazilian military failing to spot bodies or much of the floating wreckage in the search grids that were flown June 2-5, but it would be a pretty incompetent search if something as large as the VS was missed in the area searched on those days.
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Old 29th Nov 2010, 20:03
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SaturnV
There are a lot of variables that might explain the Brazilian military failing to spot bodies or much of the floating wreckage in the search grids that were flown June 2-5, but it would be a pretty incompetent search if something as large as the VS was missed in the area searched on those days.
I think you have "hit the nail on the head" - as much of the info I have seen was related to grids prepared for searching, but no confirmation that they had ever been flown. This I believe was due to miscellaneous flotsum and so-called oil slicks being sighted well to the SE of the Last Known Position. The "focus" of the search became "blurred".

With regard to individual items, I will give you an example of the Outer Spoiler located about 42NM to the N by E of TASIL on 13 June. Between the time it was first sighted and its actual recovery, it drifted to the WSW at a speed of 0.5m/s (1 knot).

mm43
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Old 30th Nov 2010, 03:10
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Hopefully in the 8 months between phase 3 and 4, those responsible have started from scratch. If there were some false assumptions and conclusions directing the earlier searches, then hopefully these have been identified and eliminated. The best way of doing this would be to bring in some new people. Otherwise it is all too easy to keep "confirming" previous errors.

It is important to know exactly what areas were searched initially (as opposed to what had been planned to be searched), as well as the meteorological conditions that may have impacted on these searches. If there was low cloud or rain or even haze, then lots of things would have missed by relatively fast moving fixed wings at 1000-1500'. Bodies most definitely would have been - they are difficult enough to see even with good visibility from a helicopter at 500-700'. Think how small people on the ground look from a 10 or 15 level building. And that is looking at the entire person - not just that bit above the water.

The other thing to consider is how many white caps there were on the waves. If there were lots of white caps, it can be hard to see light colored objects. Even a VS. All you see are hundreds of white caps in all directions - and you try and look to see which ones persist and may be something, and which ones disappear and are just breaking water. You can't keep asking the pilot to go back and circle every possible piece of debris or else you will never complete the assigned grid.

I suspect that air searches sound most easy and reliable to those who have never spent hours staring out over lots of empty water. If you listen to the accounts of survivors at sea, a common statement is how many aircraft flew over them with out seeing them.

I can only assume that they have established what areas were searched in the first few days, and the degree of confidence that can be attached to these searches.
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Old 30th Nov 2010, 11:38
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Originally Posted by JD-EE
GB, I'd agree with you except that I take these two threads here as evidence that a premature partial release of "everything" would likely be very harmful to a effort to realize a dispassionate explanation of the crash
Is it partial or is it everything ... ?

Here is a poor argument to justify a need for only limited transparency.
It is not a time to definitely explain the crash, this is the time to explore any possibilities and for that, the more heads the better, but transparency is crucial.
Passionate/Dispassionate ... what's the problem ?
Harmful to whom ?
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Old 30th Nov 2010, 12:46
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Harmful to whom ?
Well, only four main players - picking one, or two, or three which would be easy. The fourth, only aviation.
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Old 30th Nov 2010, 19:38
  #2507 (permalink)  
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In Politics, it is always toxic to try to "hide" information. For once, Politics is in there next to reality; the reality Leopard is lurking, and there will be losses. As wes says, the biggest loss will be to Aviation. The unmitigated hubris is starting to bloom, in public. (imo).

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Old 30th Nov 2010, 21:57
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I know the location of the captains body being found away from the FO's makes it speculation that he probably wasn't in the cockpit. A previous post stated that and it may or not be true. If the flight is more than 8 hrs each crew member is required to be off duty to make the flight legal. Usually it is divided up evenly so everybody gets a couple hours rest. Look at the recent Air India incident when the captain went back to pee and the FO pushed on the control column adjusting his seat and went into a high speed dive because he was inexperienced and in that case incompetent. Sometimes you have to use what you have left to keep control. I'm not saying holding attitude and gps ground speed would have worked but it probably was all they had. Hopefully they will recover the black boxes but doubt it will happen.
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Old 30th Nov 2010, 22:26
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In the very early days of the original thread (now in Tech Log) it was reported that the body of the CA was one of those recovered. The others were pax and FA(?). None were the other two pilots. Posters familiar with the AF crew rotation routine on this RIO-CDG route and the timing of the events indicated that the CA would likely have been "in the back". Recall also that a section of a "crew rest" module was among the aircraft parts recovered. There was supposition that the CA may have returning to the FD as a result of the turbulence.

Last edited by kappa; 30th Nov 2010 at 22:40.
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Old 30th Nov 2010, 22:35
  #2510 (permalink)  
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Kappa

Captain Dubois (Marc) was found among the other passengers, and it would have been unlikely for him to have been in the Rest Module. Captains rest is just aft the cockpit, a cot and a curtain, as I understand it. No ID was forthcoming as to his injuries, I believe the "Seated" pax were described as having injuries consistent (patent) with those in seats at impact. He most likely would have been unbelted or loosely restrained? As it happens I believe his rest was up at 0200, the time of beginning of upset? He likely took off, captured cruise, and left the cockpit, first rest. He was due back in the cockpit at 0200, as described by other AF crew familiar with procedure on this flight, as I recall.

cheers

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Old 30th Nov 2010, 22:48
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Bear, I'll accept your memory. I just wanted to respond to Tokyo Geoff that there was reasoning behind the "supposition" and "speculation" that preceded the recent post in this thread by p51guy.

I just modified my post to refer to the original thread now in Tech Log.
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Old 30th Nov 2010, 23:54
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kappa

got it.....
 
Old 1st Dec 2010, 03:23
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How did lack of airspeed data cause AF-447 to enter an unrecoverable stall?

The most likely theory for the crash at this time seems to be that the aircraft entered a violent storm, the pitot tubes froze over, and the pilots stalled the aircraft b/c they didn't have reliable airspeed data. I don't really understand why a lack of airspeed data could lead to a stall. I fly hang gliders and have no indication of my airspeed, yet I can still keep it from stalling - because I know that if I shift the CG back to a certain point it will stall so I never exceed this position. Now, I'm sure the handling of an A-330 is very different from a hang glider, but why do you need reliable airspeed data to keep from stalling? To my understanding, a stall occurs when the AoA exceeds a critical value causing boundary layer separation on the top surface of the wing and loss of lift. And as far as I know, AoA is controlled solely by the trim of the horizontal stabilizer. And a sensible pilot or flight computer would not trim the aircraft past the critical AoA. I see how a powerful updraft or tail wind could cause the wing to stall before the attitude can adjust, but couldn't that happen regardless of whether you know your airspeed or not?
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Old 1st Dec 2010, 03:30
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I am aware of all the speculation - it is precisely that.

No evidence at all, and there could be hundred and one other reasons for the Captains body being recovered without the pilots.
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Old 1st Dec 2010, 03:32
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You're right. Theplane will stall once it AoA was exceed.
But for the aircraft at cruise, in order to maintain the level altitude you need a
constant lift to counteract the weight.
So, if the pitot tube is frozen and send the data to the autopilot and
auto throttle that the airspeed was way to much higher the autothrottle will
decrease the throttle which slow your airplane down. Normally, when the aircraft
slowdown it want to go down. However since autopilot want to maintain the
altitude that pilot dial in or FMC, the autopilot will pull the nose up which increase
AOA. So the aircraft will continue to slow down and pitch up untill it stall and
then crash.

This is how I think it was work. However, may be the ice might form on the wing
and make the aircraft stall faster too.

Best regard
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Old 1st Dec 2010, 03:54
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Thanks for the reply, that makes sense. But why would the autopilot be so stupid as to exceed the critical AoA? I can't imagine that an interlock is not in place to prevent that from happening. Isn't that the whole Airbus flight control philosophy after all? And I would hope that the pilot would be smart enough not to do that either if he were flying manually.
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Old 1st Dec 2010, 04:44
  #2517 (permalink)  
 
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Wing icing at that altitude is fairly unlikely because of the OAT.

The autoflight & FBW systems most likely got into an ever worsening feedback loop and possibly exited that loop in direct law with a compromising attitude and speed. I feel fairly certain that had this happened during daylight hours, the pilots may have been able to successfully recover control of the aircraft.
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Old 1st Dec 2010, 05:04
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AFAIK, the Airbus still flys under the old mantra "power + attitude = performance".

Now I simply cannot believe that the pilots of this aircraft were a bunch of dopes, so there was some other major problem preventing their setting power and attitude to maintain a survivable speed.

So, what went wrong??? The info out there in the public domain suggests that they had valid attitiude, where were they mislead into a fatal series of errors? More importantly (to me) how can I recognise a similar chain of events setting up to hurt me???
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Old 1st Dec 2010, 08:14
  #2519 (permalink)  
 
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bearfoil, "In Politics, it is always toxic to try to "hide" information."

I believe a fellow named Assange is proving that sentence is dead wrong. Shame on you.
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Old 1st Dec 2010, 11:52
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Now I simply cannot believe that the pilots of this aircraft were a bunch of dopes, so there was some other major problem preventing their setting power and attitude to maintain a survivable speed.
I think if you add in severe turbulence, multiple systems failure warnings, possibly a wing drop stall and g forces you will fast find task saturation and loss of situational awareness would hamper any crews recovery.
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