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AF 447 Search to resume

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AF 447 Search to resume

Old 31st Mar 2011, 17:12
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dazdaz1:

The location of an oil drum was performed by the side-scan sonar. The use of any acoustic imaging, such as side-scan, requires a trade-off between resolution and range. At the frequency used for the long range search now in progress (600m either side of track), an oil drum would be an easy detection, but not necessarily an easy identification. The goal of the initial search is to find the debris field, which should be evident from numerous targets in the same vicinity. Certainly the crew are now familiar with the variability of the background in this area..

Once the general area of the debris is located, the AUVs have two other capabilities:

1. Higher frequency side-scan. I'm not sure of the exact frequencies in use, but it would be something like 150kHz for the low frequency, longer range, and 400kHz for the high frequency, shorter range, and higher resolution. This will allow better mapping of the debris field and possible identification of larger shapes.

2. Down-looking still image camera with strobe lighting. Flown at 5-20m off the bottom (depending on water clarity and how rough the terrain is at the site), many parts should be identifiable on camera, certainly anything as large as the recorders, or the section of fuselage to which they are perhaps still attached.

These AUVs do not intentionally touch the bottom and are incapable of manipulation or recovery of objects. They are the best available tool for wide area search and survey in deep water. 10,000 square km is a lot of area to search. Hopefully they won't have to search it all.

If the debris field is located, BEA is prepared to quickly begin Phase 5 of the search, with a different ship and crew. This phase will use a remotely operated vehicle (ROV). An ROV is tethered, hover capable, and equipped with manipulators and tools for any cutting and recovery. An ROV's tether (usually) delivers the high power required for maneuvering and manipulation; and it also provides the instant imaging, data and control required for interactive use. However, the tether restricts the speed of an ROV in deep water, making it a poor wide-area search tool.

Last edited by auv-ee; 31st Mar 2011 at 17:16. Reason: clarification
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Old 31st Mar 2011, 18:10
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auv-ee, Thanks for the post, understanding a bit more now.

Best wishes

Daz
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Old 31st Mar 2011, 19:07
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Verification in Phase 5

In view of the controversy that has arisen from other accident investigations in recent times (to be deliberately unspecific), I wonder if anyone agrees that the BEA might be well advised to call on one or more other agencies, before starting phase 5, to witness and monitor the recovery of the recorders and any other parts or equipment the condition of which may be crucial to the success of this investigation.

The WHOI will be conducting the operation, and can hardly be considered to have any agenda in this matter, so that's a good start. But I think the presence of air accident investigators from one or two other nations when the stuff is hauled aboard the recovery ship might in the long run be well worth all the extra cost and inconvenience. Suitable candidates that immediately spring to mind are from Australia, the U.S, and the U.K., but no doubt there are several non-Anglophone countries with investigators of sufficient competence.

Chris
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Old 31st Mar 2011, 20:00
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Originally Posted by Chris Scott
The WHOI will be conducting the operation, and can hardly be considered to have any agenda in this matter, so that's a good start.
Remember that any recovery will be performed with a different ship, assets and crew. I would not expect anyone from the WHOI/GOMAR contingent to be aboard for Phase 5, unless it was for data interpretation, as a guide to the ROV operators.
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Old 1st Apr 2011, 03:47
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Smile

Hi,

Remember that any recovery will be performed with a different ship, assets and crew. I would not expect anyone from the WHOI/GOMAR contingent to be aboard for Phase 5, unless it was for data interpretation, as a guide to the ROV operators.
The most important person to be aboard (exept the crew and eventual scientists) when black boxes are recovered is a representative of the french justice.
It must immediately put seals on the boxes when they deposit on board
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Old 3rd Apr 2011, 20:25
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BBC News reporting AF447 parts found

As per title.

BBC News - Home
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Old 3rd Apr 2011, 20:27
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The BBC has just reported that parts of the Aircraft have been found

"French investigators find parts of Air France plane which came down in the Atlantic off Brazil in 2009"

Last edited by beamender99; 3rd Apr 2011 at 20:31. Reason: Added quote from BBC web site
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Old 3rd Apr 2011, 20:29
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BBC reporting part of AF447 located

LATEST:French investigators find parts of Air France plane which came down in the Atlantic off Brazil in 2009

BBC News - Wreckage from Air France jet found in Atlantic
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Old 3rd Apr 2011, 20:35
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A better link to BBC
BBC News - Wreckage from Air France jet found in Atlantic
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Old 3rd Apr 2011, 20:43
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TF1 says:

"Investigators have " hope "of finding the black boxes from the aircraft, the debris field to be" relatively concentrated , "said the director of BEA." (Google translation)

Crash Rio-Paris : des éléments de l'avion localisés - France - TF1 News

Last edited by Leodis737; 3rd Apr 2011 at 20:56. Reason: info added
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Old 3rd Apr 2011, 20:57
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BBC site further updated with:-

France's Bureau of Investigations and Analysis (BEAR) said that plane parts of the plane had been located by the searchers, led by Woods Hole Oceanographic Institution.

"These parts have been identified by BEA investigators as belonging to the wreck of the A330-203, Flight AF 447," it added.
The bureau promised to release further information later.
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Old 3rd Apr 2011, 21:36
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Of course, of initial interest, is exactly where the wreckage has been found.... ?
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Old 3rd Apr 2011, 21:38
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I haven't been ignoring the requests for information on the current Phase 4 search, but in all honesty there is nothing to report. The problem, as has been pointed out earlier, is that the "Alucia" is not fitted with an add-on to her AIS installation which allows the capture of her position by LEO (low earth orbiting) satellites.

While writing this, I received a phone call to tell me the debris field has been located and is apparently relatively compact, as I always imagined it to be.

However, I have managed to recover some additional media coverage of the Suape pre-departure press event. The following is my translation from the "AF447 - Mutual Aid and Solidarity Association" webpage -
You will find below the first components of our monitoring of the 4th phase sea search:
  • The captain of Alucia, operated by WHOI, is Hap Hayden.
  • The vessel left the port of Suape in Brazil on Wednesday, March 23, 2011.
  • She has to travel 520 nautical miles (about 960km) before reaching the site to commence the search.
  • The average speed of the vessel is 12 knots or about 22 km/h
  • After about 43 hours of navigation, the Alucia will reach the site on Thursday, March 24 at 16.00.
During the press conference at Suape, the presence of an associations representative during the recovery phase of any debris (phase 5) was raised. Jean-Paul Troadec, director of BEA, has expressed his reluctance, announcing recently that the subject was still under discussion. It seems clear that the BEA is opposed to this decision by Thierry Mariani, Secretary of State for Transport. The representative of the Brazilian Association has responded to JP Troadec that this decision was not negotiable. The "AF447 - Mutual Aid and Solidarity Association" also maintains that its presence is essential for transparency.

David Gallo, head of U.S. operations has confirmed a weekly report of research activities will be sent. This report will be posted on the website of the association, the same day or next day at the latest.

We will report regularly on the progress of this new phase of research ...
So, there is still a bit more "ducking and diving" to take place before this event is finalized.
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Old 3rd Apr 2011, 21:59
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AFP reports

"During search operations in the sea carried out in the last 24 hours... the team on board the Alucia located parts of a plane," France's Bureau of Investigation and Analysis (BEA) said in a statement.
"These elements were identified by BEA investigators as belonging to the wreckage of the A330-203 plane, flight AF 447" that crashed, the statement said.
BEA Director Jean-Paul Troadec also told AFP that investigators have hope of finding the plane's black boxes because the debris area was relatively concentrated.
"The favourable news is that the debris area is relatively concentrated. And this gives us hope of finding the black boxes," he said.
Troadec said the parts of the wreckage that had been found consisted of "engines and certain elements of the wing."
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Old 3rd Apr 2011, 22:11
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Just wondering - how could they make this positive identification ? As much as I hope they finally found it I'm a little worried that they might have rushed the announcement. Somewhere it sounds to good to be true...
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Old 3rd Apr 2011, 22:12
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French newspaper (google translation)

Edit:

"These factors have been identified by investigators from BEA as belonging to the wreckage of the aircraft A330-203, Flight 447," said the French agency. These engines and components of the wing of the aircraft."
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Old 3rd Apr 2011, 22:24
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Somewhere it sounds to good to be true...
I think you need to give those experienced in sidescan sonar interpretation some credit for the knowledge they have obtained in interpreting the returned data. The REMUS 6000 AUVs also have the ability to carry a high resolution camera for close-up identification.
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Old 3rd Apr 2011, 22:56
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Exciting news, but as yet there seems to be no announcement on the French-language BEA website, malheureusement.

mm43's quote from the AF447 Mutual Aid and Solidarity Association:
During the press conference at Suape, the presence of an associations representative during the recovery phase of any debris (phase 5) was raised. Jean-Paul Troadec, director of BEA, has expressed his reluctance, announcing recently that the subject was still under discussion. It seems clear that the BEA is opposed to this decision by Thierry Mariani, Secretary of State for Transport. The representative of the Brazilian Association has responded to JP Troadec that this decision was not negotiable. The AF447 - Mutual Aid and Solidarity Association also maintains that its presence is essential for transparency.

Hello mm43,

Do you know who the Brazilian Association and the AF447 - Mutual Aid and Solidarity Association are, and is there any indication if they actually have representatives on board Alucia ?

Am I alone in being unclear on the criteria for the point at which Phase 4 ends, and the process of reorganisation before Phase 5 begins?
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Old 3rd Apr 2011, 23:02
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Originally Posted by Chris Scott
Am I alone in being unclear on the criteria for the point at which Phase 4 ends, and the process of reorganisation before Phase 5 begins?
Probably not. I believe that Phase 4 will end after the debris field has been adequately mapped and photographed; probably later this week.
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Old 3rd Apr 2011, 23:11
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Sounds reasonable. Four or five days would be ample time to request and organise the attendance of representatives of other agencies, particularly if they were air accident investigators.
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