EgyptAir 804 disappears from radar Paris-Cairo
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Yes, an expanding square spiral search pattern is what you would expect for a blue water search around a vague search datum point, but the recorded track pattern as seen on AIS looks to me much more like a contact investigation track.
This is a basic towed array search pattern that we use to optimize area:
The fish is towed, so anything over about 4 kts will cause it to cavitate, (or the harmonics in the umbilical) and degrade the measurements.
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Underfire
Your explanation of a possible search pattern is interesting. However, when the PMS Burullus was visible on AIS there were several puzzling things whcih do not seem to fit the scenario you have described. She was sailing at variously 0.4 kts and 0.3 kts all the time. She did not seem to be slowing to turn, it was just very, very slow all the time - and there were many observation points along its route where data was available, so this was not a sampling problem. AIS reports show many items of data, including the ships actual heading as well as its course over the ground. The heading showed that at all times when zig zagging the vessel had its head pointing NE, no matter which way it moved. When moving to its search area the heading was different, suggesting this was not just "stuck" data in the AIS stream, but was the actual heading as it moved. I guess that was holding the ship "head into the prevailing wind", but I have not checked the weather. Lastly the scale of the pattern it was sweeping was very "tight", with only 1Km - roughly 0.5 nautical mile - along each "long" leg and with 200 odd metre gaps between passes.
None of these seem to me to fit with a towed anything. Maybe it was a "dangled" something, or perhaps as has been suggested it was tracking a self powered ROV with or without an umbilical.
Any thoughts about what it was using?
Just noticed French Warship 9014 is back in the area and is "moving" in a way that suggests it is looking for something. Moving at 10 or 11 knots most of the time. There is a period where there were no position reports when it moved only a few Km in 4 hours.
And there is a survey ship - the Hugin Explorer just to the NE of the supposed site. It arrived in the area from Cyprus at 11 knots and now seems to be just drifting.
Your explanation of a possible search pattern is interesting. However, when the PMS Burullus was visible on AIS there were several puzzling things whcih do not seem to fit the scenario you have described. She was sailing at variously 0.4 kts and 0.3 kts all the time. She did not seem to be slowing to turn, it was just very, very slow all the time - and there were many observation points along its route where data was available, so this was not a sampling problem. AIS reports show many items of data, including the ships actual heading as well as its course over the ground. The heading showed that at all times when zig zagging the vessel had its head pointing NE, no matter which way it moved. When moving to its search area the heading was different, suggesting this was not just "stuck" data in the AIS stream, but was the actual heading as it moved. I guess that was holding the ship "head into the prevailing wind", but I have not checked the weather. Lastly the scale of the pattern it was sweeping was very "tight", with only 1Km - roughly 0.5 nautical mile - along each "long" leg and with 200 odd metre gaps between passes.
None of these seem to me to fit with a towed anything. Maybe it was a "dangled" something, or perhaps as has been suggested it was tracking a self powered ROV with or without an umbilical.
Any thoughts about what it was using?
Just noticed French Warship 9014 is back in the area and is "moving" in a way that suggests it is looking for something. Moving at 10 or 11 knots most of the time. There is a period where there were no position reports when it moved only a few Km in 4 hours.
And there is a survey ship - the Hugin Explorer just to the NE of the supposed site. It arrived in the area from Cyprus at 11 knots and now seems to be just drifting.
Last edited by AT1; 29th May 2016 at 08:41. Reason: Update
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Update Egypt authorities
http://www.civilaviation.gov.eg/News...s_28_5_16.html
"CAIRO - 28 May 2016
Investigation Progress Report (4) by the Egyptian Aircraft Accident Investigation Committee
The investigation committee received satellite reports of the electronic emergency signal that came out of the Emergency Locator Transmitter (ELT); which is equipment that sends automatic signals to satellite in the event of a crash or fall into water. Concerned search units were then informed of the updates recorded by the satellite to intensify searching in that area.
Efforts to search for the data recorders of the A320 continues; including the use of the most advanced search equipment of Alseamar company that was brought aboard the French vessel. The Ministry of Civil aviation has also made agreement with DOS (DEEP OCEAN SEARCH) company for other equipment with high capacity to receive signals and conduct sonar scan, in order to diversify research methods and to carry them out in the shortest time possible.
On the other hand, the investigation committee has started studying the information received from the Greek air traffic control about the accident; more information of the records of the radar that had followed the path of the plane before the accident, is expected to be also received."
"CAIRO - 28 May 2016
Investigation Progress Report (4) by the Egyptian Aircraft Accident Investigation Committee
The investigation committee received satellite reports of the electronic emergency signal that came out of the Emergency Locator Transmitter (ELT); which is equipment that sends automatic signals to satellite in the event of a crash or fall into water. Concerned search units were then informed of the updates recorded by the satellite to intensify searching in that area.
Efforts to search for the data recorders of the A320 continues; including the use of the most advanced search equipment of Alseamar company that was brought aboard the French vessel. The Ministry of Civil aviation has also made agreement with DOS (DEEP OCEAN SEARCH) company for other equipment with high capacity to receive signals and conduct sonar scan, in order to diversify research methods and to carry them out in the shortest time possible.
On the other hand, the investigation committee has started studying the information received from the Greek air traffic control about the accident; more information of the records of the radar that had followed the path of the plane before the accident, is expected to be also received."
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Looking up French warship 9104 I see her described by Wiki:
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.
Undoubtedly a very capable ship, but not the first type that springs to mind when selecting a vessel of opportunity for what amounts to hydrographic survey work.
I wonder if perhaps they are using her as a base for naval ASW helicopters to cover a large area with numerous dips of their dunking hydrophones to listen for the pinger(s). Half a dozen of those helicopters could join up a lot of dots and do vastly more acoustic searching in a limited time than a full spec hydrographic survey vessel could ever hope to achieve.
As AT1 points out, the limited track info that we have/had from AIS is not at all consistent with towing a hydrophone eel array, nor with towing a towfish. Hence my speculative conjecture, in which I should have used the word 'surmise' instead of 'conclude', that they were doing some kind of contact investigation rather than the boustrophedontical pattern of an area search.
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.
Undoubtedly a very capable ship, but not the first type that springs to mind when selecting a vessel of opportunity for what amounts to hydrographic survey work.
I wonder if perhaps they are using her as a base for naval ASW helicopters to cover a large area with numerous dips of their dunking hydrophones to listen for the pinger(s). Half a dozen of those helicopters could join up a lot of dots and do vastly more acoustic searching in a limited time than a full spec hydrographic survey vessel could ever hope to achieve.
As AT1 points out, the limited track info that we have/had from AIS is not at all consistent with towing a hydrophone eel array, nor with towing a towfish. Hence my speculative conjecture, in which I should have used the word 'surmise' instead of 'conclude', that they were doing some kind of contact investigation rather than the boustrophedontical pattern of an area search.
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In Le Monde this afternoon:
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours
Good stuff Caz
I am not sure about the ASW frequency capabilities, and the various naval assets around the world may not wish to "advertise" all their capabilities.
At least we know the passive sonar can easily detect very low freq sounds like propellors that are turning. Apparently, they can detect higher freq sounds like whale calls, which seem to be at upper range of human hearing.
Listening for "pings" that are up in the near ultrasonic range sould not be that hard for the ASW sonobouys or maybe subs. You don't need more than one ASW plane like the Orion or the new USN one to drop a dozen sonobouys in a very good pattern. The problem is revealing military capabilities. Up to me I would claim we found the beacon a hundred miles away! OTOH, if you drop a good pattern within a few clicks and don't detect the ping before the French boat does, then.........
At least we know the passive sonar can easily detect very low freq sounds like propellors that are turning. Apparently, they can detect higher freq sounds like whale calls, which seem to be at upper range of human hearing.
Listening for "pings" that are up in the near ultrasonic range sould not be that hard for the ASW sonobouys or maybe subs. You don't need more than one ASW plane like the Orion or the new USN one to drop a dozen sonobouys in a very good pattern. The problem is revealing military capabilities. Up to me I would claim we found the beacon a hundred miles away! OTOH, if you drop a good pattern within a few clicks and don't detect the ping before the French boat does, then.........
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Another warship, the "F262 Erfurt" which is described as a UN warship and also as "DE", is now heading for the area at speed from Cyprus. It may be just coincidence.
The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?
The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.
I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.
The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?
The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.
I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.
I wonder if perhaps they are using her as a base for naval ASW helicopters to cover a large area with numerous dips of their dunking hydrophones to listen for the pinger(s). Half a dozen of those helicopters could join up a lot of dots and do vastly more acoustic searching in a limited time than a full spec hydrographic survey vessel could ever hope to achieve.
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Translation from Le Monde: It will not be possible to recover the black boxes of the flight Paris-Cairo EgyptAir before at least 12 days, the time that a specialized vessel arrives on site, reported Agence France Presse (AFP) sources close of the investigation.
The Airbus A320 suddenly disappeared from radar screens at night May 19th before breaking sea between Crete and the northern coast of Egypt for reasons still unknown. Only the analysis of flight recorders, the "black boxes", will allow to know exactly the causes of the accident.
Egypt and France have signed agreements with two French companies specialized in finding shipwrecks in deep water, and Alseamar Deep Ocean Search (DOS). Forty Egyptians, including the crew, and 15 French are among the victims of the crash.
Read: What is known about the plane EgyptAir disappeared between Paris and Cairo
complementary role
"Both companies have a complementary role, the first to locate the" pings "black boxes [echo sonar emitted by their tags] the second to go down and recover" with a robot, explained AFP in Cairo a source close to the investigation who requested anonymity. But "the DOS specialized ship left the Irish Sea Saturday and will reach the presumed area of the crash in about 12 days, after embarking in Alexandria Egyptian and French investigators," she added.
The information has been confirmed by other sources close to the investigation, which evoke a depth of about 3000 meters in the research area, some 290 km north of the Egyptian coast.
Three DETECTOR-6000 Alseamar immersed equipment can detect "pings" up to 4000 to 5000 meters, were loaded aboard a French naval vessel, the Laplace, who left Corsica Thursday . It should arrive in the presumed area of the crash "Sunday or Monday at the latest," according to one source.
Automatic alerts issued
"Pending the DOS ship equipped to detect" ping "deep water but most of robots able to descend to 6000 meters to retrieve the black boxes, there will be no waste of time and since the Laplace attempt to locate the meantime, "says one of these sources, which evokes, even in 12 days," a very good chance to recover the flight recorders through the combination of the two French companies. "
Time is running out as beacons of these flight recorders can emit only "four to five weeks" before exhausting their batteries.
Read also: In Cairo, MS804 flight passengers families EgyptAir angry against the authorities
The hypothesis of the attack, initially put forward by Egypt, has lost ground to that technical incident since it was found that automatic alerts have been issued by the unit two minutes his fall, indicating smoke in the cockpit and a failure of the computer managing orders.
The Airbus A320 suddenly disappeared from radar screens at night May 19th before breaking sea between Crete and the northern coast of Egypt for reasons still unknown. Only the analysis of flight recorders, the "black boxes", will allow to know exactly the causes of the accident.
Egypt and France have signed agreements with two French companies specialized in finding shipwrecks in deep water, and Alseamar Deep Ocean Search (DOS). Forty Egyptians, including the crew, and 15 French are among the victims of the crash.
Read: What is known about the plane EgyptAir disappeared between Paris and Cairo
complementary role
"Both companies have a complementary role, the first to locate the" pings "black boxes [echo sonar emitted by their tags] the second to go down and recover" with a robot, explained AFP in Cairo a source close to the investigation who requested anonymity. But "the DOS specialized ship left the Irish Sea Saturday and will reach the presumed area of the crash in about 12 days, after embarking in Alexandria Egyptian and French investigators," she added.
The information has been confirmed by other sources close to the investigation, which evoke a depth of about 3000 meters in the research area, some 290 km north of the Egyptian coast.
Three DETECTOR-6000 Alseamar immersed equipment can detect "pings" up to 4000 to 5000 meters, were loaded aboard a French naval vessel, the Laplace, who left Corsica Thursday . It should arrive in the presumed area of the crash "Sunday or Monday at the latest," according to one source.
Automatic alerts issued
"Pending the DOS ship equipped to detect" ping "deep water but most of robots able to descend to 6000 meters to retrieve the black boxes, there will be no waste of time and since the Laplace attempt to locate the meantime, "says one of these sources, which evokes, even in 12 days," a very good chance to recover the flight recorders through the combination of the two French companies. "
Time is running out as beacons of these flight recorders can emit only "four to five weeks" before exhausting their batteries.
Read also: In Cairo, MS804 flight passengers families EgyptAir angry against the authorities
The hypothesis of the attack, initially put forward by Egypt, has lost ground to that technical incident since it was found that automatic alerts have been issued by the unit two minutes his fall, indicating smoke in the cockpit and a failure of the computer managing orders.
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Another warship, the "F262 Erfurt" which is described as a UN warship and also as "DE", is now heading for the area at speed from Cyprus. It may be just coincidence.
The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?
The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.
I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.
The track of the French warship is very very odd - with no obvious "pattern". Maybe it is searching the surface to recover floating debris spotted by helicopters or the Orion rather than an undersea search?
The Hugin Explorer has stopped drifting and is now closing at speed on the area where the French warship is.
I would have thought the military world would be OK revealing quite a lot about their ability to detect a distress "pinger" - particulary if they have had time to go to port and pick up suitable hardware. This is not going to reveal much/anything about their ability to detect ships or subs.
The French sub, The E'meraude, wasn't set up for listening for 37.5khz, nor did they know they were supposed to be, in the initial search for AF447. Looking for Black Boxes wasn't a mission they'd had. Only, maybe, after the batteries for the pingers had died, and it was too late, was The E'meraude possibly set up for 37.5khz. The area the airplane was eventually found in, had been crossed off as already searched by The E'meraude, but they were not equipted to detect 37.5khz. It's deep in the BEA report.
A hard lesson learned, so, I hope, maybe, that mistake won't be repeated.
Knock on wood. It's beginning to sound like the searchers have it under control. May not be long yet.
Last edited by Coagie; 29th May 2016 at 18:27. Reason: Punctuation
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that ship is a great C2 platform and can take on board a variety launchable vehicles that can aid the search
But to find sunken ships and aeroplanes you need ships that can find sunken ships and aeroplanes.
Coagie has pointed out that most of the naval ASW gear is not optimized for the high freq beacon we are looking for.
One current sonobouy system only goes up to 2400 Hz or so with any good sensitivity. I would imagine the subs to have much larger bandwidth, but just try to get the specs for those!!!!
As Lonewolf said, "dipping" by ASW choppers ain't gonna work. The gear is not real good when passive and needs to "ping". It is not designed for deep work, as most operational subs won't be down there at a thousand meters or more, ya think?
I would place my bets on a sub, but they can't down to the depths we are looking at, but might get a "ping" if the acoustics are right.
One current sonobouy system only goes up to 2400 Hz or so with any good sensitivity. I would imagine the subs to have much larger bandwidth, but just try to get the specs for those!!!!
As Lonewolf said, "dipping" by ASW choppers ain't gonna work. The gear is not real good when passive and needs to "ping". It is not designed for deep work, as most operational subs won't be down there at a thousand meters or more, ya think?
I would place my bets on a sub, but they can't down to the depths we are looking at, but might get a "ping" if the acoustics are right.
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Okay, so why would you select an amphibious assault ship with helicopters to find a wreck in three thousand metres of water?
Just askin 'cos I doan unnerstand.
I sort of understood why the RN offered the services of a passing "coalition" RFA, but that was a matter of hours after the aircraft went down.
What, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?
Okay, I'll give you that, but what, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?
Just askin 'cos I doan unnerstand.
I sort of understood why the RN offered the services of a passing "coalition" RFA, but that was a matter of hours after the aircraft went down.
What, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?
Don't forget there's also the 'fishing immigrants out of the sea' operations going on in this approximate area.
Last edited by Cazalet33; 29th May 2016 at 21:27.
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9104 is not "Tonnerre"
@Cazalet33
Helicopter Carrier Tonnerre was not dispatched for supporting this operation. So this tag "9104" is more likely given to PHM Jacoubet which is, since May 23, only doing surface sweep and visual researches for debris and they deployed two aircraft, a Falcon 50 and Atlantic 2, in addition to Egyptian and US assets deployed.
See official French Navy media, 28 May situation :
Vol Egyptair : Point de situation au 28 mai | colsbleus.fr : le magazine de la Marine Nationale
Hydro Vessel Laplace would be on spot by tomorrow with pinger locators. Search for beacon will start then. Next, in about a dozen days, they would be joined by Deep Ocean Search R/V John Lethbridge (sailing from Ireland sea) for the deep sea recovery mission.
Deep Ocean Search - Home
Looking up French warship 9104 I see her described by Wiki:
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.
Tonnerre (L9014; lit. Thunder) is an amphibious assault helicopter carrier of the Marine Nationale.
See official French Navy media, 28 May situation :
Vol Egyptair : Point de situation au 28 mai | colsbleus.fr : le magazine de la Marine Nationale
Hydro Vessel Laplace would be on spot by tomorrow with pinger locators. Search for beacon will start then. Next, in about a dozen days, they would be joined by Deep Ocean Search R/V John Lethbridge (sailing from Ireland sea) for the deep sea recovery mission.
Deep Ocean Search - Home
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AT!,
Yes, that is correct. The explanation in the post was regarding searching with a towed array. The pattern shown in one of my last posts was not a general search pattern. It is also not indicative of ROV deployment. An ROV is not towed around, it is self powered. The ship must remain relatively stationary, or basically on station, not moving at all, moving perhaps in 5m increments, the DP keeping it as stationary as possible.
The concept is to hold, and let the ROV drive around. One cannot have too much slack in the umbilical, as the current drag on the line would be too difficult for the ROV to overcome, and you dont drag the ROV around.
They may have deployed the towed device that looks for the pinger. It is tough with only one vessel as one cannot triangluate.
Cheers
Yes, that is correct. The explanation in the post was regarding searching with a towed array. The pattern shown in one of my last posts was not a general search pattern. It is also not indicative of ROV deployment. An ROV is not towed around, it is self powered. The ship must remain relatively stationary, or basically on station, not moving at all, moving perhaps in 5m increments, the DP keeping it as stationary as possible.
The concept is to hold, and let the ROV drive around. One cannot have too much slack in the umbilical, as the current drag on the line would be too difficult for the ROV to overcome, and you dont drag the ROV around.
They may have deployed the towed device that looks for the pinger. It is tough with only one vessel as one cannot triangluate.
Cheers
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From Le Monde 29/05
"Trois DETECTOR-6000 d’Alseamar, engins immergés capables de détecter les « pings » jusqu’à 4 000 à 5 000 mètres, ont été embarqués à bord d’un bâtiment de la Marine française, le Laplace, qui a quitté la Corse jeudi. Il doit arriver dans la zone présumée du crash « dimanche, ou lundi au plus tard », selon une des sources."
English Translation: 3 Alseamar DETECTOR-6000's, devices capapble of detecting the "pings" to a depth of 4000 to 5000 metres, were taken on board a French Marine vessel, the Laplace , which left Corsica on Thursday. It should arrive in the presumed crash area by "Sunday, or Monday at the latest", according to one of the sources.
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours
"Trois DETECTOR-6000 d’Alseamar, engins immergés capables de détecter les « pings » jusqu’à 4 000 à 5 000 mètres, ont été embarqués à bord d’un bâtiment de la Marine française, le Laplace, qui a quitté la Corse jeudi. Il doit arriver dans la zone présumée du crash « dimanche, ou lundi au plus tard », selon une des sources."
English Translation: 3 Alseamar DETECTOR-6000's, devices capapble of detecting the "pings" to a depth of 4000 to 5000 metres, were taken on board a French Marine vessel, the Laplace , which left Corsica on Thursday. It should arrive in the presumed crash area by "Sunday, or Monday at the latest", according to one of the sources.
EgyptAir : les boîtes noires ne seront pas repêchées avant 12 jours
Okay, I'll give you that, but what, on earth, is an amphibious assault ship with helicopters doing in a hydrographic job?
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BPC Tonnerre is in Pacific Ocean
I just wonder why there is still people talking about BPC Tonnerre and researches for MS804 while she is actually part of the Naval Group Jeanne d'Arc sailing in the Pacific Ocean with FLF Guépratte.
There was US Marines from Okinawa visiting Tonnerre... a few days ago.
Coopération franco-américaine pour le groupe Jeanne d?Arc
There was US Marines from Okinawa visiting Tonnerre... a few days ago.
Coopération franco-américaine pour le groupe Jeanne d?Arc