AF 447 Search to resume
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Hi,
Seem's it's becoming a jump game ...
Maybe the boxes will never be recovered .. and only speculations supported by the BEA in a final report will add nothing to learn about this crash for any improvement (s) of flying safety.
At least a lesson is learned ... ?
The black boxes are designed only for be recovered from a ground crash or a crash in shallow water ...
For deepest water (the majority of the seas overflyed ) it's to be lucky.
Lucky is not a word (normally) used in the aviation world
So this design is a flaw and must be corrected ASAP.
If action is taken .. this crash will not be useless.
Seem's it's becoming a jump game ...
Maybe the boxes will never be recovered .. and only speculations supported by the BEA in a final report will add nothing to learn about this crash for any improvement (s) of flying safety.
At least a lesson is learned ... ?
The black boxes are designed only for be recovered from a ground crash or a crash in shallow water ...
For deepest water (the majority of the seas overflyed ) it's to be lucky.
Lucky is not a word (normally) used in the aviation world
So this design is a flaw and must be corrected ASAP.
If action is taken .. this crash will not be useless.
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Hello,
Very good findings. This illustrate in some way that without much more informations about context, it will be hardly possible to make any accurate ACAR interpretation. One really need a simulator to explore each case.
A more appropriate term should have been used like: "oxygen masks were not deployed" but most of A319 systems are quite similar to A330 ones.
About the search, it is too bad that nothing was spotted but signal analysts could certainly work out another search plan at a later date; hence, if nothing is found before the end of this campaign, I'm pretty confident that there will be another one to find the wreckage, at whatever additional cost.
S~
Olivier
Originally Posted by Diversification
I found the following statements in one of my files:
"Report No: 4/2009. Report on the serious incident to Airbus A319-111, registration G-EZAC, near Nantes, France on 15 September 2006
Loss of both airspeed data sources due to loss of the power supplies to ADIRUs 1 and 3.... ADIRU:s 1 and 3 feed data to the cabin pressure controllers. De-energisation of the AC BUS 1 and AC ESS busbars prevents CPC 1 and CPC 2 from operating, because of the loss of power and loss of ADIRU data. Cabin pressurisation would then need to be controlled manually by the crew. The excess cabin altitude warning system would still be operational....
Other significant systems were affected, such as the cabin pressurisation system, where the automatic control function was no longer available. In this incident it did not cause the flight crew any difficulty, however had this failure occurred in other circumstances, the cabin altitude could increase excessively, requiring corrective action. The flight crew would then have to control the cabin pressure manually. Whilst the excessive cabin altitude warning would still operate, it would not be possible to deploy the passenger oxygen masks."
Hence, in the cited case it may be possible to have a loss of hull pressure without oxygen mask deployment.
"Report No: 4/2009. Report on the serious incident to Airbus A319-111, registration G-EZAC, near Nantes, France on 15 September 2006
Loss of both airspeed data sources due to loss of the power supplies to ADIRUs 1 and 3.... ADIRU:s 1 and 3 feed data to the cabin pressure controllers. De-energisation of the AC BUS 1 and AC ESS busbars prevents CPC 1 and CPC 2 from operating, because of the loss of power and loss of ADIRU data. Cabin pressurisation would then need to be controlled manually by the crew. The excess cabin altitude warning system would still be operational....
Other significant systems were affected, such as the cabin pressurisation system, where the automatic control function was no longer available. In this incident it did not cause the flight crew any difficulty, however had this failure occurred in other circumstances, the cabin altitude could increase excessively, requiring corrective action. The flight crew would then have to control the cabin pressure manually. Whilst the excessive cabin altitude warning would still operate, it would not be possible to deploy the passenger oxygen masks."
Hence, in the cited case it may be possible to have a loss of hull pressure without oxygen mask deployment.
Originally Posted by mm43
Puts a different complexion on the "No Decompression" statement, though I note the type you quoted was an A319.
About the search, it is too bad that nothing was spotted but signal analysts could certainly work out another search plan at a later date; hence, if nothing is found before the end of this campaign, I'm pretty confident that there will be another one to find the wreckage, at whatever additional cost.
S~
Olivier
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takata;
Possibly the Cabin Alt went above 9,550 feet at a rate greater than 1,800 ft/min - loss of pressure, but not decompression.
For the SATCOM to operate, it needs primary sources #1 or #2, or the APU. So the likelihood of the Oxygen Masks not being deployable in this instance seems remote?? But, wait a minute, the Cabin Vertical Speed warning could have queued in the ACARS sequence and been transmitted some time after the event, e.g. on a restart after a flameout or on APU start.
Just another angle on it.
The general idea was that they were going to "mow the lawn", and though they got side tracked by new information, to continue with their prime objective will in the end produce results. Like you, I am confident they will continue, as there are too many unanswered questions, and a lot of Euros that need accounting for.
mm43
Possibly the Cabin Alt went above 9,550 feet at a rate greater than 1,800 ft/min - loss of pressure, but not decompression.
originally posted by PJ2 ...
The #1 CPC is powered by the DC ESSential bus, the #2 CPC is powered by the DC1 bus and CPC Manual Control is provided by the DC BATtery bus.
So yes, the control of cabin pressure would have been fully available with APU and even with with no APU with manual control from the DC BAT bus.
The #1 CPC is powered by the DC ESSential bus, the #2 CPC is powered by the DC1 bus and CPC Manual Control is provided by the DC BATtery bus.
So yes, the control of cabin pressure would have been fully available with APU and even with with no APU with manual control from the DC BAT bus.
Just another angle on it.
The general idea was that they were going to "mow the lawn", and though they got side tracked by new information, to continue with their prime objective will in the end produce results. Like you, I am confident they will continue, as there are too many unanswered questions, and a lot of Euros that need accounting for.
mm43
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Hi mm43,
I don't think they could have experienced any electrical failures before both engine possibly stopped, and if they stopped, it was after this last ACAR was sent, not before. Any relight would trigger engines/electrical fault related ACARS in priority over any cockpit advisory. Consequently, it seems hard to find any trace of such flameout during the sequence 02.10-02.14.
S~
Olivier
I don't think they could have experienced any electrical failures before both engine possibly stopped, and if they stopped, it was after this last ACAR was sent, not before. Any relight would trigger engines/electrical fault related ACARS in priority over any cockpit advisory. Consequently, it seems hard to find any trace of such flameout during the sequence 02.10-02.14.
S~
Olivier
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Does anybody else think that they spent a surprisingly small amount of time at the new search area indicated by the analysis of the acoustic recordings? And, if I am interpreting the data correctly (which I may well not be), they didn't even cover the search area very thoroughly. It would seem to me that, considering that this is the closest thing they've had to a solid lead for the location of the recorders, they would be concentrating in that area and working outwards from it.
Either way, my fingers are crosses for them finding it - it would be dreadful to leave this event in such a state of mystery.
Either way, my fingers are crosses for them finding it - it would be dreadful to leave this event in such a state of mystery.
CABIN VERTICAL-SPEED ADVISORY − an Hypothesis
Quote from takata:
“I don't think they could have experienced any electrical failures before both engine possibly stopped, and if they stopped, it was after this last ACAR was sent, not before. Any relight would trigger engines/electrical fault related ACARS in priority over any cockpit advisory. Consequently, it seems hard to find any trace of such flameout during the sequence 02.10-02.14.”
Am unable to research this myself, due to the limitations of my current dial-up internet connection, but I accept that analysis.
So, returning to the cabin V/S advisory, we seem to be left with two possibilities:
(1) spurious cabin V/S signal for 5 secs or more, due perhaps to electrical transient;
(2) cabin V/S exceeding 1800 ft/min, for 5 seconds or more.
Looking at (2), and assuming that any CPC failure would trigger an ECAM warning of higher priority than this advisory, the most likely cause would be a cabin differential pressure approaching zero, in an aircraft descent of over 1800ft/min. − as HazelNuts39 proposed here on May08/11:35z. For the descending aircraft to “catch up with the cabin” − in the absence of failure of packs, bleeds or CPCs − it would be passing an altitude of about 6000ft.
So I offer the following hypothesis, based on HazelNuts39’s original idea, to be challenged:
02:10:14z
Last-known Position, apparently (?) cruising at FL350, cabin altitude ~6000ft.
02:11z
Control has been lost, for reasons unclear in the absence of the DFDR and CVR. Aircraft now descending at variable (high) rate.
With many hours to go before planned TOD, and no change of altitude selected on the FCU or FMGC, the duty CPC maintains current cabin altitude.
02:14z
Aircraft passes 6000ft in the descent, taking the cabin altitude with it (the Negative Relief Valve has opened). Cabin V/S increases rapidly through (minus) 1800ft/min.
02:14:26z
ACARS transmits Cabin V/S advisory, already shown on cockpit ECAM display.
02:15:14z
“Planned” ACARS message not transmitted, due to absence of AC power.
The latter could be due to impact with the surface, double engine-failure (extreme hail?), or AC electrical-failure (extreme lightning-strike).
Chris
“I don't think they could have experienced any electrical failures before both engine possibly stopped, and if they stopped, it was after this last ACAR was sent, not before. Any relight would trigger engines/electrical fault related ACARS in priority over any cockpit advisory. Consequently, it seems hard to find any trace of such flameout during the sequence 02.10-02.14.”
Am unable to research this myself, due to the limitations of my current dial-up internet connection, but I accept that analysis.
So, returning to the cabin V/S advisory, we seem to be left with two possibilities:
(1) spurious cabin V/S signal for 5 secs or more, due perhaps to electrical transient;
(2) cabin V/S exceeding 1800 ft/min, for 5 seconds or more.
Looking at (2), and assuming that any CPC failure would trigger an ECAM warning of higher priority than this advisory, the most likely cause would be a cabin differential pressure approaching zero, in an aircraft descent of over 1800ft/min. − as HazelNuts39 proposed here on May08/11:35z. For the descending aircraft to “catch up with the cabin” − in the absence of failure of packs, bleeds or CPCs − it would be passing an altitude of about 6000ft.
So I offer the following hypothesis, based on HazelNuts39’s original idea, to be challenged:
02:10:14z
Last-known Position, apparently (?) cruising at FL350, cabin altitude ~6000ft.
02:11z
Control has been lost, for reasons unclear in the absence of the DFDR and CVR. Aircraft now descending at variable (high) rate.
With many hours to go before planned TOD, and no change of altitude selected on the FCU or FMGC, the duty CPC maintains current cabin altitude.
02:14z
Aircraft passes 6000ft in the descent, taking the cabin altitude with it (the Negative Relief Valve has opened). Cabin V/S increases rapidly through (minus) 1800ft/min.
02:14:26z
ACARS transmits Cabin V/S advisory, already shown on cockpit ECAM display.
02:15:14z
“Planned” ACARS message not transmitted, due to absence of AC power.
The latter could be due to impact with the surface, double engine-failure (extreme hail?), or AC electrical-failure (extreme lightning-strike).
Chris
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Search Fails to Yield Black Box of French Jet
By NICOLA CLARK
PARIS — A weeklong search of a patch of mid-Atlantic seabed has failed to find any trace of an Air France jet that crashed almost a year ago, a spokeswoman for France’s air accident investigation agency said on Thursday.
Search boats had interrupted their hunt in a different 1,200-square mile zone on May 6 and raced to an area about 40 miles to the southwest that French naval investigators had identified using a new computer analysis of sonar recordings made in the weeks after the crash on June 1, 2009. Recently developed software had picked up what investigators were convinced was the distinctive signal from at least one of the “pingers” attached to the jet’s two flight recorders.
A Norwegian ship equipped with two underwater drones mounted with ultra-high resolution cameras and a remote-controlled minisubmarine scoured an 80-square-mile rectangle centered over the area where naval investigators calculated was the beacon’s most likely point of origin, said Martine Del Bono, a spokeswoman for the Bureau of Investigations and Analyses. Investigators said the water there ranged from 8,500 to 12,000 feet deep.
“We have made a thorough search but we have unfortunately been unable to find even the smallest piece of metal, not a trace of the wreckage,” Ms. Del Bono said.
At a briefing on Monday, investigators said that the remains of the plane were likely to be lying in a relatively limited debris field of a few hundred square yards.
All 228 passengers and crew members were killed when Air France Flight 447, an Airbus A330, went down in heavy thunderstorms en route to Paris from Rio de Janeiro. Sea searches last year recovered more than 600 pieces of floating debris and 51 bodies, but the flight recorders and the bulk of the wreckage were not found.
Without the recorders, also known as “black boxes,” investigators have said it might never be possible to determine the cause of the disaster. So far, the main source of information about what happened has been a series of messages sent automatically from the plane to a maintenance base, which indicated there was a malfunction of the plane’s airspeed sensors.
Representatives of the victims’ families said they were devastated by the news. “After all of the hope that was raised by the Ministry of Defense a week ago, this comes as an enormous disappointment,” said Robert Soulas, a spokesman for Entraide et Solidarité AF447, a group representing relatives of 60 of the dead.
In a statement late on Wednesday, the accident investigation bureau said it would continue to work with the navy to “work on the accuracy” of its sonar analysis. But with a May 25 deadline for the completion of the latest search operation approaching, investigators felt it was best for the search boat, with its crew of 50 technicians, resume its work in the initial search zone, which was defined using computer models of currents and wind direction in the days after the crash.
“We do not want to lose any more time,” Ms. Del Bono said.
Stéphanie Prunier, a spokeswoman for the Defense Ministry, conceded that the navy’s data “did not yield the fruits that we had hoped,” but said it was still too early to dismiss its findings. “We are continuing our work on the frequencies,” she said, referring to the sonar analysis. “The information may still prove useful, but it may take some time.”
By NICOLA CLARK
PARIS — A weeklong search of a patch of mid-Atlantic seabed has failed to find any trace of an Air France jet that crashed almost a year ago, a spokeswoman for France’s air accident investigation agency said on Thursday.
Search boats had interrupted their hunt in a different 1,200-square mile zone on May 6 and raced to an area about 40 miles to the southwest that French naval investigators had identified using a new computer analysis of sonar recordings made in the weeks after the crash on June 1, 2009. Recently developed software had picked up what investigators were convinced was the distinctive signal from at least one of the “pingers” attached to the jet’s two flight recorders.
A Norwegian ship equipped with two underwater drones mounted with ultra-high resolution cameras and a remote-controlled minisubmarine scoured an 80-square-mile rectangle centered over the area where naval investigators calculated was the beacon’s most likely point of origin, said Martine Del Bono, a spokeswoman for the Bureau of Investigations and Analyses. Investigators said the water there ranged from 8,500 to 12,000 feet deep.
“We have made a thorough search but we have unfortunately been unable to find even the smallest piece of metal, not a trace of the wreckage,” Ms. Del Bono said.
At a briefing on Monday, investigators said that the remains of the plane were likely to be lying in a relatively limited debris field of a few hundred square yards.
All 228 passengers and crew members were killed when Air France Flight 447, an Airbus A330, went down in heavy thunderstorms en route to Paris from Rio de Janeiro. Sea searches last year recovered more than 600 pieces of floating debris and 51 bodies, but the flight recorders and the bulk of the wreckage were not found.
Without the recorders, also known as “black boxes,” investigators have said it might never be possible to determine the cause of the disaster. So far, the main source of information about what happened has been a series of messages sent automatically from the plane to a maintenance base, which indicated there was a malfunction of the plane’s airspeed sensors.
Representatives of the victims’ families said they were devastated by the news. “After all of the hope that was raised by the Ministry of Defense a week ago, this comes as an enormous disappointment,” said Robert Soulas, a spokesman for Entraide et Solidarité AF447, a group representing relatives of 60 of the dead.
In a statement late on Wednesday, the accident investigation bureau said it would continue to work with the navy to “work on the accuracy” of its sonar analysis. But with a May 25 deadline for the completion of the latest search operation approaching, investigators felt it was best for the search boat, with its crew of 50 technicians, resume its work in the initial search zone, which was defined using computer models of currents and wind direction in the days after the crash.
“We do not want to lose any more time,” Ms. Del Bono said.
Stéphanie Prunier, a spokeswoman for the Defense Ministry, conceded that the navy’s data “did not yield the fruits that we had hoped,” but said it was still too early to dismiss its findings. “We are continuing our work on the frequencies,” she said, referring to the sonar analysis. “The information may still prove useful, but it may take some time.”
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Update: "Seabed Worker" - position
The following position places the vessel well to the west of the "pinger" zone. There could be a simple explanation, i.e. contrary to the BEA's earlier announcement that the vessel would resume searching in Zone 1, a decision was made to extend the pinger zone search.
12 May 2010 22:02z Hdg 087.0 Spd 02.8 2°42'02"N 31°25'00"W
The graphic in Post #1013 has been updated to correct the positions previously plotted - they were all south by 2 minutes.
The position above is 10NM west of the left most meridian, and I suspect the "Seabed Worker" has launched her AUV's from a position further to the west and is tracking them on an easterly heading at 2.8 knots along the center-line of the search box.
mm43
12 May 2010 22:02z Hdg 087.0 Spd 02.8 2°42'02"N 31°25'00"W
The graphic in Post #1013 has been updated to correct the positions previously plotted - they were all south by 2 minutes.
The position above is 10NM west of the left most meridian, and I suspect the "Seabed Worker" has launched her AUV's from a position further to the west and is tracking them on an easterly heading at 2.8 knots along the center-line of the search box.
mm43
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Update: "Seabed Worker" - positions
The "Seabed Worker" has now returned to the Zone 1 search area and her latest available positions are:-
13 May 2010 10:19z Hdg 345.2 Spd 00.5 3°05'30"N 31°10'08"W
13 May 2010 08:45z Hdg 173.7 Spd 01.0 3°05'21"N 31°10'03"W
These indicate that she has resumed searching from where she left off on 6 May.
Edit: Further update:-
13 May 2010 20:51z Hdg 212.3 Spd 00.9 3°04'12"N 31°08'03"W
13 May 2010 19:11z Hdg 015.9 Spd 06.2 3°06'13"N 31°05'07"W
The following graphic shows the latest position -
mm43
13 May 2010 10:19z Hdg 345.2 Spd 00.5 3°05'30"N 31°10'08"W
13 May 2010 08:45z Hdg 173.7 Spd 01.0 3°05'21"N 31°10'03"W
These indicate that she has resumed searching from where she left off on 6 May.
Edit: Further update:-
13 May 2010 20:51z Hdg 212.3 Spd 00.9 3°04'12"N 31°08'03"W
13 May 2010 19:11z Hdg 015.9 Spd 06.2 3°06'13"N 31°05'07"W
The following graphic shows the latest position -
mm43
Last edited by mm43; 15th May 2010 at 03:44. Reason: added updated graphic
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These indicate that she has resumed searching from where she left off on 6 May.
Now, back to the job in hand ....
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Originally Posted by ushumgal
ushumgal wrote:
Does anybody else think that they spent a surprisingly small amount of time at the new search area indicated by the analysis of the acoustic recordings? And, if I am interpreting the data correctly (which I may well not be), they didn't even cover the search area very thoroughly.
Does anybody else think that they spent a surprisingly small amount of time at the new search area indicated by the analysis of the acoustic recordings? And, if I am interpreting the data correctly (which I may well not be), they didn't even cover the search area very thoroughly.
Judging from the REMUS 6000 Specifications - Kongsberg Maritime, the vehicle can travel at 2.5m/s, but round that down to a typical 2m/s. Thus the vehicle can cover about 600m^2/s, which is a bit more than 2km^2/hour. The vehicle can be in mission at the bottom for about 20 hours/24hours (if things go well, BEA mentioned the 20 hours, and that's consistent with the vehicle specs), which makes 40km^2/day. That is for covering every patch of ground twice with one vehicle.
The area BEA marked on their figure, is 12km by 25km = 300km^2. If the above figures are right, that would require 7.5 vehicle-days. They have two vehicles, so they would need about 4 working days. They arrived on site May 6 and probably would have to spend a day deploying transponders and surveying their location. So they may have had the AUVs down for a good part of May 7 through May 11. That's 5 days. BEA reported that they did not survey as fast as they would like because of some vehicle problems, so it's anyone's guess how much that might have changed things. May 12 was probably used to retrieve the transponders. So a full survey is at least plausible at 300m sonar range.
Originally Posted by ushumgal
It would seem to me that, considering that this is the closest thing they've had to a solid lead for the location of the recorders, they would be concentrating in that area and working outwards from it.
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Update: "Seabed Worker" - position
The latest positions are:-
13 May 2010 20:51z Hdg 212.3 Spd 00.9 3°04'12"N 31°08'03"W
13 May 2010 19:11z Hdg 015.9 Spd 06.2 3°06'13"N 31°05'07"W
The graphic at Post #1027 has been updated.
mm43
13 May 2010 20:51z Hdg 212.3 Spd 00.9 3°04'12"N 31°08'03"W
13 May 2010 19:11z Hdg 015.9 Spd 06.2 3°06'13"N 31°05'07"W
The graphic at Post #1027 has been updated.
mm43
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The NY Times wrote:
At a briefing on Monday, investigators said that the remains of the plane were likely to be lying in a relatively limited debris field of a few hundred square yards.
At a briefing on Monday, investigators said that the remains of the plane were likely to be lying in a relatively limited debris field of a few hundred square yards.
This might be reasonable for the major debris but I bet there is small stuff spread over a wider area. Judging from the recovered debris, there must have been many small, possibly light pieces. These would drift with the current before landing, while heavier parts, like an engine would fall faster.
The average surface current in the area is seasonal in both direction and magnitude (The North Equatorial Counter Current). It would appear from that source that the surface current in the target area is dominated, in June, by the southern equatorial current, with a velocity of 0.1-0.3m/sec. This is not likely a constant all the way down (a related article from the same site mentions opposing under currents at 300m farther north), so estimating about 1/3 of the average surface current would be about 0.06m/s. A rough number for sure.
The only decent rate data point I recall is for a manned submersible I used to work on, which is about 8m long, 2.5m wide, and weighted with 200kg; in this configuration it sinks at about 0.5m/s. In a 4000m dive it might thus drift 500m horizontally in a 0.06m/sec current.
An A330 engine is smaller and denser than the sub (GE - Aviation: CF6). At about half the cross-sectional area and roughly 10 times the in-water weight, it should fall about 6 times faster. (drag = weight at terminal velocity, and drag is proportional to area and to velocity squared). The horizontal drift would thus be on the order of 80m.
Surely there are many small parts, such as pieces of sheet metal or luggage, that would fall more slowly than the sub, say at 0.1-0.2m/s. resulting in horizontal drift of 1200-2500m.
So it seems like the heavy debris would be in area a few hundred meters across, but there is likely a lot of lighter stuff spread farther. Also, any part whose sinking was delayed by slow flooding of an air pocket, would land even farther down-current.
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I tend to believe that the debris field would not be as large as one might think. Depending upon what happened to the airplane after making contact with the water, if it did not fail and separate into several parts, while being airborn, then most should rest fairly close together on the bottom. The EgyptAir 990, while structural failure occured at altitude, remained at two relatively small areas. The bulk of the airplane's fuselage, wings, engines, gear, etc footprint was only approximately 70 X 80 meters. Of course, this was in 220 feet of water, quite different from the search now going on. Even so, I would think that the main part of the airplane and large parts would not have drifted that much.
ww
ww
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Originally Posted by wes_wall
I tend to believe that the debris field would not be as large as one might think. Depending upon what happened to the airplane after making contact with the water, if it did not fail and separate into several parts, while being airborn, then most should rest fairly close together on the bottom. The EgyptAir 990, while structural failure occured at altitude, remained at two relatively small areas. The bulk of the airplane's fuselage, wings, engines, gear, etc footprint was only approximately 70 X 80 meters. Of course, this was in 220 feet of water, quite different from the search now going on. Even so, I would think that the main part of the airplane and large parts would not have drifted that much.
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Thanks for your informed comments, auv-ee! 
This has probably been answered before, but does anyone know roughly the 'resolution' of the detectors being used? I.e., how small a piece of metal is still likely to be detected?
Reverting briefly to the acoustic detection a year ago, I wonder what effect that tall ridge (running northwest) to the north of the new search area would have on a pinger lying on the ocean floor. If the submarine was to the south of it and the pinger north of the ridge, would the ridge tend to block the sound from it, or would the ridge in fact help deflect the sound upwards to where the submarine was? Just an idle thought I had, knowing nothing of underwater acoustics.
This has probably been answered before, but does anyone know roughly the 'resolution' of the detectors being used? I.e., how small a piece of metal is still likely to be detected?
Reverting briefly to the acoustic detection a year ago, I wonder what effect that tall ridge (running northwest) to the north of the new search area would have on a pinger lying on the ocean floor. If the submarine was to the south of it and the pinger north of the ridge, would the ridge tend to block the sound from it, or would the ridge in fact help deflect the sound upwards to where the submarine was? Just an idle thought I had, knowing nothing of underwater acoustics.
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Hi there. For the small dispersion of the debris on the seabed, the SHOM (Navy Hydrographic Services) produced during the 1st phase of the sea searches a 3D map of the currents in the area of interest, some slices (currents as a function of depth or currents 1000m-deep) are visible in
http://www.bea.aero/fr/enquetes/vol....hom.050609.pdf
And other usefull parameters, like for the pingers detection, or about the nature of the seafloor, etc...
Also wondered about the opportunity to redeploy the search means in the area 1 previously being scanned: maybe to give some time to the Navy and Thales to refine their estimation, or provide new ones... while continuing the job that needs to be done (before the 25th of may) near the back drifted area. With the hope to go south again with new search directions.
Jeff
http://www.bea.aero/fr/enquetes/vol....hom.050609.pdf
And other usefull parameters, like for the pingers detection, or about the nature of the seafloor, etc...
Also wondered about the opportunity to redeploy the search means in the area 1 previously being scanned: maybe to give some time to the Navy and Thales to refine their estimation, or provide new ones... while continuing the job that needs to be done (before the 25th of may) near the back drifted area. With the hope to go south again with new search directions.
Jeff
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Originally Posted by Hyperveloce
For the small dispersion of the debris on the seabed, the SHOM (Navy Hydrographic Services) produced during the 1st phase of the sea searches a 3D map of the currents in the area of interest, some slices (currents as a function of depth or currents 1000m-deep) are visible in
http://www.bea.aero/fr/enquetes/vol....hom.050609.pdf
http://www.bea.aero/fr/enquetes/vol....hom.050609.pdf
For those who may be interested.
Here is a specific example of using “Occam” in a situation like this:
(As usual, I will preface my comments by saying that I am giving an example, based on the information publicly available. I am NOT saying that I am certain, or even confident, this is what happened. What I am saying is: Absent other information, and using certain info that is available, I am led in this direction as a possibility that is more likely than some others.)
Given:
1. The BEA reported that (at least) 43 of the 50 bodies recovered displayed very similar serious compression injuries/fractures.
2. Those bodies were of passengers widely dispersed throughout the aircraft (according to seat assignments).
3. The simplest (reasonable) explanation for facts 1 and 2 is that all sections of the aircraft impacted in the same fashion. Why? Because the contemplation of other scenarios requires a great deal of coincidence. It is possible that a more complex , and statistically far less probable, chain of events could give the same result. BUT it’s not nearly as likely. For the vast majority of bodies from all parts of the aircraft to exhibit the same injury patterns, the simplest and most likely explanation is that those passengers all exhibited very similar injuries because passengers from all parts of the aircraft were subject to the same impact dynamics.
4. The simplest (reasonable) explanation for statement 3 is that the aircraft was intact on impact.
5. Therefore, it is more likely the aircraft did not break up prior to impact.
Occam at work.
And to repeat for emphasis: The above is not a conclusion. It is a possible scenario, made more likely than some others, in the light of known facts only.
grizz
Here is a specific example of using “Occam” in a situation like this:
(As usual, I will preface my comments by saying that I am giving an example, based on the information publicly available. I am NOT saying that I am certain, or even confident, this is what happened. What I am saying is: Absent other information, and using certain info that is available, I am led in this direction as a possibility that is more likely than some others.)
Given:
1. The BEA reported that (at least) 43 of the 50 bodies recovered displayed very similar serious compression injuries/fractures.
2. Those bodies were of passengers widely dispersed throughout the aircraft (according to seat assignments).
3. The simplest (reasonable) explanation for facts 1 and 2 is that all sections of the aircraft impacted in the same fashion. Why? Because the contemplation of other scenarios requires a great deal of coincidence. It is possible that a more complex , and statistically far less probable, chain of events could give the same result. BUT it’s not nearly as likely. For the vast majority of bodies from all parts of the aircraft to exhibit the same injury patterns, the simplest and most likely explanation is that those passengers all exhibited very similar injuries because passengers from all parts of the aircraft were subject to the same impact dynamics.
4. The simplest (reasonable) explanation for statement 3 is that the aircraft was intact on impact.
5. Therefore, it is more likely the aircraft did not break up prior to impact.
Occam at work.
And to repeat for emphasis: The above is not a conclusion. It is a possible scenario, made more likely than some others, in the light of known facts only.
grizz
Join Date: Jun 2009
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ushumgal;
The answer to your question is hidden a few pages back in this thread Post #792 and www.searchforamelia.org, but put simply, the resolution is relative to the scanning frequency and distance from target. A related post on using CHIRP technologies to enhance spatial resolution is at Post #799.
The following is from a post I made to the the original AF447 thread (now languishing in the Tech Log), and gives you a realistic view of what was achieved 8 years ago, but bear in mind that the resolution of the sidescan sonar doing the initial search is lower, but still high enough to detect engine cores and anything bigger, e.g wings/fuselage sections.
The effectiveness of multibeam sonar in detecting specific parts of the debris is not doubted. C & C Technologies, Inc. Autonomous Underwater Vehicle (AUV) can operate at a depth of 4,500m and the resolution of the multibeam sonar in 2002 produced the following for the BBC of wreckage of a Fairey Swordfish Mk1 and a Hangar Lift Deck which parted company with HMS "Ark Royal" when it sunk in 1066m of water in 1941.
The yellow and cyan description/text has been added by me.
For good measure, here is a photo of a Fairey Swordfish ("Stringbag") on a Royal Navy carrier deck.
Finding one large part, will lead to finding the rest. So, if the debris field is a little larger than is currently being talked about, that increases the chances of it being found in the search mode.
Edit: added links to previous posts and to Search for Amelia
mm43
The answer to your question is hidden a few pages back in this thread Post #792 and www.searchforamelia.org, but put simply, the resolution is relative to the scanning frequency and distance from target. A related post on using CHIRP technologies to enhance spatial resolution is at Post #799.
The following is from a post I made to the the original AF447 thread (now languishing in the Tech Log), and gives you a realistic view of what was achieved 8 years ago, but bear in mind that the resolution of the sidescan sonar doing the initial search is lower, but still high enough to detect engine cores and anything bigger, e.g wings/fuselage sections.
The effectiveness of multibeam sonar in detecting specific parts of the debris is not doubted. C & C Technologies, Inc. Autonomous Underwater Vehicle (AUV) can operate at a depth of 4,500m and the resolution of the multibeam sonar in 2002 produced the following for the BBC of wreckage of a Fairey Swordfish Mk1 and a Hangar Lift Deck which parted company with HMS "Ark Royal" when it sunk in 1066m of water in 1941.
The yellow and cyan description/text has been added by me.
For good measure, here is a photo of a Fairey Swordfish ("Stringbag") on a Royal Navy carrier deck.
Finding one large part, will lead to finding the rest. So, if the debris field is a little larger than is currently being talked about, that increases the chances of it being found in the search mode.
Edit: added links to previous posts and to Search for Amelia
mm43
Last edited by mm43; 15th May 2010 at 00:43.