Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

AF 447 Search to resume

Tech Log The very best in practical technical discussion on the web

AF 447 Search to resume

Old 24th May 2010, 20:34
  #1141 (permalink)  
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,584
Originally Posted by bearfoil
Had it not been determined that 447 was tracking left?
- no, as far as I am aware.
BOAC is offline  
Old 24th May 2010, 20:54
  #1142 (permalink)  
Join Date: Mar 2009
Location: S23W046
Age: 69
Posts: 57
As to BEA report LRP has been in fact slightly left of track.
Flyinheavy is offline  
Old 24th May 2010, 22:13
  #1143 (permalink)  
Join Date: Jan 2008
Location: Blighty (Nth. Downs)
Age: 72
Posts: 2,052
Flight beyond 02:14:45z


The problem with flight beyond 02:14:45z is that − as was pointed out to me recently − unless the ACARS transmission system coincidentally became u/s (aerial damage, or plain bad luck), or its aerial lost sight of the satellite (unusual A/C attitude), the first engine (and/or its AC generator) to fail would itself have resulted in at least one ACARS message. By the same logic, there needed to be an almost simultaneous failure of both engines’ AC generators to disable ACARS transmission of the first such failure.

If the BEA is right, the absence of the predictable FCPC1`(PRIM 1) FAULT message at 02:14:45 can only be explained by one of the above events having taken place between 02:14:26 (Advisory, Cabin VS) and 02:14;45.

Like you and others, I share Hyperveloce’s concern that the SW quadrant of the 40nm circle should be searched, asap. But we're not paying...

Chris Scott is offline  
Old 24th May 2010, 23:40
  #1144 (permalink)  
Join Date: Jun 2009
Location: Paris
Posts: 691
Originally Posted by Chris Scott
FlexibleResponse stated here that “you also need to take into account that the human body does not float in seawater until about 72 hours after death. Then there should be some allowance for the time from establishing positive buoyancy to float from the wreckage at the bottom of the ocean up to the surface. Again some allowance should be made for the average sea current during the ascent time…” (etc.)
Not sure if FlexibleResponse’s assertion has been challenged since but, if not, it put the crash zone back into the circle of 40nm radius.
Well Chris, FlexibleResponse's assumption of 72 hrs after death for body surfacing is not valid at sea into such context:
A very large majority of people are naturally buoyant into sea water while a majority of them will also sink into non salted water. Moreover, people which are not naturally buoyant will sink into such a great depth that they would possibly never surface again due to very high pressure (slow decomposition -very low temp- would not overcome such pressure). Remember that the ocean floor is 2,000-4,000 meters deep around this zone.
As a matter of fact, all models used for locating the wreckage (US, Russian, French, etc.) were considering that the recovered bodies drifted at the surface from the crash time.
takata is offline  
Old 24th May 2010, 23:45
  #1145 (permalink)  
Join Date: Jun 2009
Location: Chesapeake Bay
Age: 75
Posts: 57
Bearfoil: Not sure if you got your total body count from my typo. I had typed 53 in an earlier post when it should have been "50 identified bodies" (per BEA 2nd Interim Report). Post corrected.

Chris Scott: Thank you again for your clarity. You would improve any logical analysis. Wish we had a wall chart showing weighted probabilites and those little triangular If/Then icons. Would need a large wall. Would be dense with facts and maybes.


Last edited by GreatBear; 25th May 2010 at 00:08. Reason: Changed What/If to If/Then
GreatBear is offline  
Old 25th May 2010, 00:23
  #1146 (permalink)  
Join Date: Aug 2009
Location: Germany
Age: 63
Posts: 1,809

Le Figaro - France : Les recherches de l'AF 447 virent au conflit d'experts

The research of AF 447 saw the conflict of experts

INFO LE FIGARO - The third season of research should be completed Tuesday morning on a failure. The BEA and the army opposed to the position of the wreckage.

The drama of the AF 447 is a mystery for now. The third season of research should be completed Tuesday morning on a failure because the investigators are currently on route Recife in Brazil without being able to locate the wreckage. Yet, despite two months of operation in the South Atlantic, the uncertainty has never been greater, as the experts disagree on the position of the device.

Background. On April 28, investigators returned to Recife to BEA after one month of research at sea after a crew change, they go back to finish searching the area for the third campaign. This area of 2500 km2 was defined from the study of drift of aircraft debris and the bodies of victims recovered in June 2009. A week later, once the theater. The army announced that it detected the signal from the black box: it is a distributed signals heard in June by the nuclear submarine, the Emerald and managed to positively identify the signal emitted by the black boxes of ten months AF447 earlier. "We sent twenty Emerald positions when the signal was seen black boxes," says one close to the matter. This new area south of the last known position of the device indicates that the Air France flight was turned around before crashing into the ocean.

The Seabed Worker, who participates in research 40 nautical miles further north, was immediately dispatched. It passes the new area in detail. In vain. "There was nothing to find in the south, said a member of the investigation. Everything has been raked. "Seabed The Worker then finish off again to explore the area of the BEA without broadening the scope defined by the army. "They spent 24 hours and no more on our area," says a source at the Ministry of Defence. The ocean is vast and we are the only ones to offer a scientific data and tangible. "

Reportedly, the Army has conducted tests in the Mediterranean with black boxes to identify their signal. According to a source close to the BEA, focusing on sounds recorded in June 2009, the Army had confused signals trials in the Mediterranean and those of the AF 447. She would have indicated an area that was not good investigators. "There has never been south of 447 AF, we lost one week, said a relative of BEA. The Navy wanted further work before announcing anything but the Ministry of Defence wanted to communicate quickly and we cut the grass under foot. "

"Explanations unclear»

Since then, relations between the BEA, under the Ministry of Transportation and the Ministry of Defence will be a bit cold. "The explanation of the army are unclear insists near BEA, and since it's radio silence on the subject. Asked by the Figaro, the army has not this story:" We are The third deterrent to the world and we are not here to please public opinion, says a source at the Ministry of Defence. We have removed some positions, but we maintain that certain positions are communicated to BEA correct. They have not been explored: BEA prefer to say that the army was wrong rather than saying that we received the signal from the black boxes but no one may know where he ever comes. "

The propagation of sound in water environment is indeed very complex. The black boxes of the Ethiopian Airlines jet that crashed last January off the coast of Lebanon were heard at 16 nautical miles from the crash site while recording only emit 5000. "If nuclear deterrence is hiding under water, is that this environment is complex," said one source at the Ministry of Defence. Today we have the probabilities of position of the wreckage. '

A fourth round is planned

The failure of this third season does not mean that the wreckage of flight AF 447 will never be found. Indeed, a fourth phase of research could be organized after-school new data from the army and the drift models of aircraft debris. The BEA has been able to study up on the drift and returns with data finer than the models that have so far been exploited.

"It is sufficient that the BEA was mistaken from 0.2 to 0.3 knots (about 0.4 to 0.6 km / h, Ed) for our area is the same," says a source at the Ministry of Defence. The echoes of the AF 447 will also be re-analyzed. The definition is complicated by their position on terrain and the phenomena of echoes. Asked by Le Figaro, a government source said "there is little chance that this new campaign, if it occurs, should be held before next autumn."
jcjeant is offline  
Old 25th May 2010, 00:47
  #1147 (permalink)  
Posts: n/a
Great Bear,

As Chris Scott has said (eloquently so), precision is unnecessary thus far. Not a conscious mistake, but I was using your number. My purpose in noting that there were more identified remains than the 43 mentioned in BEAII was to illuminate a device BEA have used, and committed disrespect for those unmentioned. Only those injuries considered useful to support the conclusion of 'seated, vertically accelerated' were noted, and those of the others not mentioned at all. This is a callous act in my view, again, too soon for conclusions, and to present evidence at all, before all hope is lost of recovery of the recorders is precipitous.

More examples of minor propaganda? Where is the photograph of the spoiler? Was it left out due to its marked difference in the sequence of destructive forces at work?
Where is the opinion on the Leading edge collapse of the V/S? With sufficient Lateral energy to fail the V/S on AA587, it too looked in rather good shape after it fell into the sea from altitude. Compare? Contrast?

Why is the Vertical take up arm featured as substantive re: Vertical failur? Look at the environment in the photo closely, The end of the arm failed in the vertical, but the Hinge is undamaged? The "Lateral Rods" between the V/S paired mounts show failure, but look closely, the failure was not in the vertical at all, but in the designed for direction, laterally. Why is the attachment point for the V/S a tab of Resin inside a saddle of Steel? Two Phase does not do focal Stress well at all, but makes up for it in its resilience when Stress is "Spread". Why are the Lateral rods attached to the same rail? With a stagger, they could be twice their length, and save the V/S in case of critical lateral loading, even past the failure and loss of the Rudder. Ah, Weight and Money.

At some point I'll attempt to bring together the thoughts of the devil's advocate.
Every table set for investigative thinking and discussion should have at least one maverick, no?

all the best

Old 25th May 2010, 01:53
  #1148 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 76
Posts: 1,331
Update: "Seabed Worker" - position

The latest available positions show the vessel working in an area previously covered by "Anne Candies".

24 May 2010 16:35 Hdg 134.2 Spd 09.4 3°30'07"N 30°35'28"W
24 May 2010 05:57 Hdg 178.4 Spd 04.0 3°32'54"N 30°32'32"W
24 May 2010 04:16 Hdg 290.9 Spd 01.3 3°34'02"N 30°35'40"W
24 May 2010 02:59 Hdg 294.4 Spd 01.1 3°33'25"N 30°34'16"W
23 May 2010 17:46 Hdg 021.1 Spd 10.6 3°19'31"N 30°40'46"W
23 May 2010 16:20 Hdg 276.5 Spd 00.6 3°05'42"N 30°45'08"W
23 May 2010 07:11 Hdg 255.9 Spd 00.8 3°04'59"N 30°41'40"W
23 May 2010 05:30 Hdg 101.1 Spd 10.3 3°06'41"N 30°49'52"W
23 May 2010 03:45 Hdg 303.9 Spd 01.0 3°10'42"N 30°49'13"W
22 May 2010 19:00 Hdg 082.3 Spd 07.2 3°28'58"N 30°34'25"W


Last edited by mm43; 25th May 2010 at 02:10.
mm43 is offline  
Old 25th May 2010, 02:41
  #1149 (permalink)  
Join Date: May 2010
Location: MA, USA
Posts: 126
Originally Posted by me
I am puzzled by the northern excursion on 5/22. Based on the times of the preceding and trailing positions at the south westerly search area, they spent less than 20hours at the northern site, possibly much less. One of those positions is on the eastern edge of search zone 2 of BEA's 5/4 extended search areas.
Ahhh. Light dawns on Marblehead. The latest positions show Seabed worker at search zone 2. I'm now sure the run up there on 5/22 was to drop and survey transponders, thus saving time when returning to search that area on 5/24.
auv-ee is offline  
Old 25th May 2010, 03:32
  #1150 (permalink)  
Join Date: Jul 2009
Location: Not far from a big Lake
Age: 77
Posts: 1,457
The Stall Scenario

I suppose if AF447 did the decel into a deep stall scenario, it would be found much closer to the last known position than the bulk of the search has been looking at.
Looks like the doughnut hole inside of the present search area might be a prime candidate. After all, how did it hit so slow?? Had to be well under 200 knots just based on the condition of the bodies, and the large size of the found wreckage.
If AF447 was drifting heading slowly on its way down, it would be even closer to the LKP. Maybe they have been searching too far out?
Machinbird is offline  
Old 25th May 2010, 03:53
  #1151 (permalink)  
Join Date: Jun 2009
Location: Chesapeake Bay
Age: 75
Posts: 57
Thanks for the SEABED WORKER position updates, mm43.

Auv-ee and Machinbird: But why search Zone 2 at the latitude where the first body was discovered, when it is known that the cluster of bodies in that area was moving northward at about 20nm/day? Am I missing some major eddy or whirl or stasis that would have kept the bodies neatly on station around 3º30' N from June 1 until June 6, when they then commenced their northward drift (see post #1120)? Got any ideas, mm43?

I do hope the strategic thinking and best-guesses behind the search scheme eventually see the light of day, and don't drown in increasingly difficult internecine politics (thanks for the sad Navy vs. BEA story from LE FIGARO, jcjeant). We interested outliers are certainly working from a great deal of obtuse and inferred data points, unlike the experts presently in the kitchen. As I've said before, it would be nice to have regular information-rich updates direct from the scene -- a facility easily arranged in this day and age. But then that information might be more difficult to manage.

GreatBear is offline  
Old 25th May 2010, 04:08
  #1152 (permalink)  
Join Date: May 2002
Location: GC Paradise
Posts: 1,020
Not sure if FlexibleResponse’s assertion has been challenged since but, if not, it put the crash zone back into the circle of 40nm radius.
Yes my post was challenged very quickly. I was incorrect and I now agree fully with takata, in that beyond a certain depth, a body will not float to the surface.
FlexibleResponse is offline  
Old 25th May 2010, 04:44
  #1153 (permalink)  
Join Date: May 2010
Location: MA, USA
Posts: 126
Originally Posted by GreatBear
But why search Zone 2 at the latitude where the first body was discovered,...
Zone 2 was an area of uncertain coverage by the Orion towed sonar. Whether or not anyone, including BEA, actually believes the a/c could be in zone 2, I expect they need to be able to say that they covered the whole search area completely, and there is no possibility that the target was missed. Then, if there is a 4th attempt, they don't have to revisit or defend old uncertainties.
auv-ee is offline  
Old 25th May 2010, 05:55
  #1154 (permalink)  
Join Date: Jun 2009
Location: NNW of Antipodes
Age: 76
Posts: 1,331
originally posted by Great Bear ...
Am I missing some major eddy or whirl or stasis that would have kept the bodies neatly on station around 3º30' N from June 1 until June 6, when they then commenced their northward drift (see post #1120)?
The surface current was a bit of an unknown quantity between 3°N and 3°30'N, though in theory it should have been NE and turning through to N at 3°30'N and then depending on the Long would take you to the north of TASIL or further to the west. The velocity would appear to have been a little less than that observed post 6 June, and knowing the areas searched by the FAB, that effectively means that the current was moving NNE through to N to the west of the LKP. It could well be that a stream was flowing from around 2°30'N 31°20'N in a NNE direction and on approaching 3°N branched both left to N and right to NE, then sort of paralleled up again to become N by E. What happened in the middle would be anyone's guess.

The question of leeway for the bodies needs to be addressed, but post 6 June the wind was generally light and from an easterly quarter. Some bodies may have floated initially, and others will have sunk to an equilibrium point, and depending on water temperature at that point will have eventually made their way to the surface. Warm temps mean this happened more quickly than in temperate latitudes.

The Port Outer Spoiler was found 40NM N by E of TASIL on 13 June, and if the bodies and the vertical stabilizer hadn't been subject to some leeway due to windage, I would have expected them all to have finished up passing close by TASIL. That wasn't the case, and the vertical stabilizer was located some distance to the west of the nearest bodies, which indicates that the wind had played a part in its total drift.

My first look at the problem using OSCAR and QuikSCAT data lead me to place the impact position near 3°N and 31°10'W, and one of those positions was south of the LKP and hasn't been looked at in this phase 3 search. My present thinking based on updated information still comes up with a position near the north side of the southwest quadrant at around 2°49'N 31°06'W. In due course I'll put up a graphic to show how that is achieved, but in any-case the fact that most of the area to the north has been searched and found devoid of any debris, doesn't mean that my position is any better that any other guess at this stage.

I'm disappointed to read that according to Le Figaro the BEA and the Ministry of Defence are having a spat over the existence or not of pinger records.

mm43 is offline  
Old 25th May 2010, 08:55
  #1155 (permalink)  
Join Date: Jun 2009
Location: Paris
Posts: 691
Hello mm43,
Originally Posted by mm43
The question of leeway for the bodies needs to be addressed, but post 6 June the wind was generally light and from an easterly quarter. Some bodies may have floated initially, and others will have sunk to an equilibrium point, and depending on water temperature at that point will have eventually made their way to the surface. Warm temps mean this happened more quickly than in temperate latitudes.
Opinions of experts about it is that bodies which will sunk will sunk directly to the bottom of the sea while bodies which will float will be almost invisible (99.9% submerged) from the surface during the first few days (which explain why they could have been flown over at close range without being spotted during the initial aerial search and rescue phase). There is no equilibrum point to be reached at any depth (passed 10 meters the pressure is twice the surface).
Originally Posted by mm43
I'm disappointed to read that according to Le Figaro the BEA and the Ministry of Defence are having a spat over the existence or not of pinger records.
I'm very disappointed about that too. Most of this clash is due to hastily communication from MoD (not from Navy) which disrupted BEA's systematic search plan while those data aquired were still too raw to be fully exploited.

The good point is that Emeraude's sensors actually recorded those pingers along 20 positions and that they are actually very real. As it is explained, the uncertaincy about location is still great because distances are very difficult to compute due to the complexity of the relief. It means that the search zone may be far away than first computed. The example given about the localisation of Lebanon pingers +10 nautic miles farther than supposed range of emission is a good clue about all the difficulties encountered to pin point an exact location.
Now, the positive point is that a fourth search will be conducted with certaincy and that only time will permit to fully analyse Navy findings.
takata is offline  
Old 25th May 2010, 09:32
  #1156 (permalink)  
Join Date: Jan 2008
Location: Blighty (Nth. Downs)
Age: 72
Posts: 2,052
Body buoyancy and drift

takata and FlexibleResponse,

Thanks for revisiting your discussions of 11 months ago, some of which I had missed. Am looking forward to mm43’s promised graphic-explanation of his estimated impact positions, which have been consistently well to the west of the body-based one that you (takata) proposed last June 21st. Are body reverse-drift calculations more reliable than debris, due to less windage-effect?

Chris Scott is offline  
Old 25th May 2010, 09:54
  #1157 (permalink)  
Join Date: Jul 2009
Location: France - mostly
Age: 80
Posts: 1,689
Tape mixup?

There are some puzzling details in Fabrice Amadeo’s FIGARO story.
On 6 may 2010 the website of french weekly ‘Le nouvel observateur’ quotes general Christian Babtiste, spokesman for the ministry of defense as saying that the pinger sound has been identified on tapes obtained on 1st july 2009:
"La marine nationale a fait un effet de loupe sur ces enregistrements et a confirmé la possibilité que ce qui était entendu était bien des signaux émis par ces boîtes noires". L'enregistrement étudié avait été réalisé le 1er juillet 2009.
From BEA 2nd Interim Report, Appendix 2:
Durant l’opération de recherche, la base support du SNA a conduit des essais en Méditerranée à partir d’un bâtiment du même type afin de vérifier et d’optimiser les performances du senseur utilisé. Les résultats de ces essais ont permis de définir de nouveaux réglages pour accroitre les capacités de détection de l’intercepteur de l’Emeraude (distance de détection de 2 000 mètres du 10 au 30 juin, étendue à environ 3 200 mètres du 1er au 10 juillet).
My translation:
During the search operation, the SNA support base has conducted tests with a ship of the same type in the Mediterranean sea to verify and optimize the performance of the sensor that was used. The results of these trials permitted to define new settings to increase the detection capability of Emeraude’s receiver (detection range 2000 m from 10 to 30 june, extended to about 3200 m from 1st to 10 july).

In other words, the tapes obtained in the mediterranean were dated before july 1st.

HazelNuts39 is offline  
Old 25th May 2010, 10:29
  #1158 (permalink)  
Join Date: Mar 2010
Location: London
Posts: 29
Lost:The Mystery of Flight 447
BBC2 Sun 30 May 2010 22:00 &
Wed 2 Jun 2010 00:20

BBC - BBC Two Programmes - Lost: The Mystery of Flight 447
eireoflot82 is offline  
Old 25th May 2010, 10:44
  #1159 (permalink)  
Join Date: Mar 2001
Location: us
Posts: 694
Has a more precise map been publicly published of where all the larger pieces of the plane were recovered, and when? For example, if I recall correctly, at least one of the cabin crew seats was recovered, presumably entire with harness and frame, as it was determined that the seat was unoccupied at the time of impact. (Which I found rather surprising by itself.) I suspect that enough of the seat would be submerged as to introduce a considerable drag and be less affected by wind-induced drift.
SaturnV is offline  
Old 25th May 2010, 10:57
  #1160 (permalink)  
Join Date: May 2010
Location: SW from BUD
Age: 49
Posts: 1
may 6 - 12 seach zone

I'm new here, and also not having any sonar experience, just some basics in acoustics. I overthought the may 6 - 12 "navy_search" and based on this drafted a small extended search zone, maybe someone more experienced comment on this. ( I think that the french navy's signal detection has more precise position compared to the backdrifted vertical stabilizer, just some interpretation is missing from the results ).

the following contains a lot of guesses:

- first guess ( may be ruled out by navy ): the navy used a signal processing which traded in directional sensitivity for signal to noise ratio, to rise the signal above background noise, this way the direction information was lost, they could only tell the location of Emeraude where the signal could be rised from background noise. Based on this, probably line shape, BEA made a search zone in the long axis of this position with a few nautical mile border. In this case the highest signal level probably was detected, with the Emeraude in the center of the navy_search_zone.

- the search in this zone found nothing, but if the navy could pesuade BEA to look there, then the detection had to be strong enough, but if nothing was there then the signal maybe travelled there on other ways. The attenuation of the pinger signal on this frequency doesn't allow direct detection from great distances sideways from the ocean bottom. my guess is: a natural amplifier had to amplify the signal to be detectable from greater distance.

- the vertical center of the sofar channel, based in the june 6 BEA celerity data, was in 700 - 900 m depth

- as far as I know sofar channel entered sound reaches specific depth in more or less circular patterns/spots, the attenuation in horizontal distance, and the max height reached during propagation depends on incident angle of the sound, a relatively shallow incident angle causes sound to propagate further, but not reaching high enough, a close to vertical incident angle enables reaching the surface but not propagating horizontally.

- there is an underwater mount ( red in bathymetry ) North-East from the supposed Emeraude position, if the color code is identical with the earlier published BEA bathymetry scale, then the top of the mountains are in the middle, middle-bottom of the sofar channel.

- the South-West side of this mountain is very steap, and three few nm sized parabolic like shapes may be identified on it.

- my guess is: a pinger located around the verical focal plane of these parabolas on the ocean bottom could concentrate the pinger signal into
the sofar channel, the incident angle beeing not horizontal, the signal travelled in the sofar channel with larger vertical swings, and one of these swings reached Emeraude.

Emeraude could detect it only at the place where the upper peaks in the channel were, and because swing length can be significant, maybe this was the first place from the mountain, or maybe further places can be identified with the same processing which was done with sonar data ( but if the Emeraude track distance was not enough fine, during the first search, then further refinement may not be made ).

I don't say that these shapes are perfectly formed parabolas, in the need of acoustic reflections ( if I estimate correctly then pinger wavelength is around 4 cm ) but may contain alligned surfaces wich concentrate waves.

I think I would take a look at S-W from the mountain, where the base of the perpendicular from the Emeraude highest detection position to the mountain is.

- if the wreck is there then the mountain blocked any signals into the direction of the largest part of the search zone
- there is a wide flat bottom area, between the Emeraude and the mountains, which may helped the propagation.
- if the pinger had been located on top of the mountain in 800 - 1000 m depth then it could also penetrate the sofar channel, but then it had to be heard from other positions also.
- if the pinger had been located further to the N-E direction then the mountain would block at least partially the sofar channel, preventing it to reach Emeraude in the middle of the navy_search area.
- the published diving depth for the french rubis class submarines are 300 m, and if the published rating is "low profile" then it could be in a depth of 400 - 500 m-s which made it possible to pick up the pinger signal.

Further bathimetry, west from the navy_search_zone was not done, but if similar sea mounts are present west of it but close to the navy search zone,
I would look there also.

I made this simple drawing based on the BEA bathymetry, I would search the yellow bordered area, and if I had time constraints I would take a look at least at the middle and the south-east one of the three parabolic shaped formations.
iabel is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.