Way up in the thread, we were told that the black-box locator beacons were only 'visible' within around a 6km range, and that was the limiting factor i.e. you had to be pretty much on top of the box, to detect it. Why is it that, now they have had supposed pings from the box, they still have a massive search area ?
Secondly, given that they have some fairly sophisticated sonar direction-finding equipment, why have they not been able to home in on the supposed pings that they have heard, rather than apparently being able to say nothing more definite than the fact it is in the sea, somewhere ?
Way up in the thread, we were told that the black-box locator beacons were only 'visible' within around a 6km range, and that was the limiting factor i.e. you had to be pretty much on top of the box, to detect it. Why is it that, now they have had supposed pings from the box, they still have a massive search area ?
Secondly, given that they have some fairly sophisticated sonar direction-finding equipment, why have they not been able to home in on the supposed pings that they have heard, rather than apparently being able to say nothing more definite than the fact it is in the sea, somewhere ?
Sound does strange things in water. There are thermal layers which can play havoc with acoustics, to such an extent that submarines can hide beneath the boundaries between one temperature and another.
The ping will also be radiating in all directions so if you detect a ping, all you can really say is that you're in range. It could be directly below or off to the side in any direction, and by any distance. That's why it's important to get as many contacts as possible, and for as long as possible. If you can hold a "ping" you can pootle along and listen for the signal getting stronger or weaker. Even then, when the signal is at is strongest, all you can say is that you've probably crossed a line on which the pinger may be lying.
Add in the fact that if the pinger is, for example, at the base of big rock formation, you might not be able to detect it from one direction as the rocks will mask the ping.
Way up in the thread, we were told that the black-box locator beacons were only 'visible' within around a 6km range, and that was the limiting factor i.e. you had to be pretty much on top of the box, to detect it. Why is it that, now they have had supposed pings from the box, they still have a massive search area ?
Secondly, given that they have some fairly sophisticated sonar direction-finding equipment, why have they not been able to home in on the supposed pings that they have heard, rather than apparently being able to say nothing more definite than the fact it is in the sea, somewhere ?
Due to the Pings received they have narrowed the search area to something like 5 by 7 KM
Sound does strange things in water. There are thermal layers which can play havoc with acoustics, to such an extent that submarines can hide beneath the boundaries between one temperature and another.
The ping will also be radiating in all directions so if you detect a ping, all you can really say is that you're in range. It could be directly below or off to the side in any direction, and by any distance. That's why it's important to get as many contacts as possible, and for as long as possible. If you can hold a "ping" you can pootle along and listen for the signal getting stronger or weaker. Even then, when the signal is at is strongest, all you can say is that you've probably crossed a line on which the pinger may be lying.
Add in the fact that if the pinger is, for example, at the base of big rock formation, you might not be able to detect it from one direction as the rocks will mask the ping.
I know it does strange things, but not that strange...
(My 'area' is radar and electronic warfare, but it is pretty analogous to sonar)
At a basic level, if you have a bit of direction finding kit, it will have, let's say, 16 receivers sat in a circle. By analysing the relative signal strengths at each receiver, then you can work out pretty well where that signal is coming from. It'll be stronger (and earlier) on one side than the other, and that gives you your lead.
It may sound high-tech, but these navies have very high-tech kit. Imagine if you couldn't work out even vaguely where an enemy submarine was because 'sound does strange things in water'. In fact, the direction finding kit is usually set up to analyse very broad bands of signal frequencies, so the fact you are looking for just one makes it, theoretically, easier.
I'm sure they know what they're doing, but I'm wondering if they are on a bit of a wild goose chase again at the moment...
It may sound high-tech, but these navies have very high-tech kit. Imagine if you couldn't work out even vaguely where an enemy submarine was because 'sound does strange things in water'. In fact, the direction finding kit is usually set up to analyse very broad bands of signal frequencies, so the fact you are looking for just one makes it, theoretically, easier.
Perhaps they're using higher tech kit than they're letting on.
Might buy one to look for a bar of soap in the bath.
On a serious note they face a difficult job because of all the rubbish on the sea floor. About twenty years ago they thought they had found a Swissair fuselage only to find later it was a WW2 sub.
I know it does strange things, but not that strange...
(My 'area' is radar and electronic warfare, but it is pretty analogous to sonar)
At a basic level, if you have a bit of direction finding kit, it will have, let's say, 16 receivers sat in a circle. By analysing the relative signal strengths at each receiver, then you can work out pretty well where that signal is coming from. It'll be stronger (and earlier) on one side than the other, and that gives you your lead.
It may sound high-tech, but these navies have very high-tech kit. Imagine if you couldn't work out even vaguely where an enemy submarine was because 'sound does strange things in water'. In fact, the direction finding kit is usually set up to analyse very broad bands of signal frequencies, so the fact you are looking for just one makes it, theoretically, easier.
I'm sure they know what they're doing, but I'm wondering if they are on a bit of a wild goose chase again at the moment...
I'm not sure that the "looking for a submarine" analogy really works. They tend not to be 4,500 feet deep!
Increasing the distance by a factor of 4 or 5 is going to significantly increase the margin of error.
They have not heard any since last tuesday, l really don't know what Houston has been waiting for, other than his obsession with debris.
The question of debris (and anyone's "obsession" with it) is fairly irrelevant in terms of the underwater search. Identifiable debris would prove that the plane had crashed, but bearing in mind the extreme difficulty in back-predicting the ocean currents and winds, it wouldn't narrow the search area.
The only way of narrowing the search area was to listen for pings, and it would have been ridiculous not to allow a margin on the expected life of the batteries. After all, there's no immediate rush to map the floor. A few days isn't going to make any difference as the one thing we do know is that if the plane is down there, it isn't going anywhere!
There's a theory that the plane never existed, the people aren't missing at all
I'm not quite sure what the basis of that theory is
I'd suggest that isn't a conspiracy theory ... it's a conspiracy fantasy! As such, I think the "basis" is probably a fertile imagination, a degree of paranoia, and too much cheese before bedtime!
There's a theory that the plane never existed, the people aren't missing at all
I'm not quite sure what the basis of that theory is
That CT comes from one of the relatives who were waiting at the airport to collect their family member. When there was no sign of the plane landing, they enquired how long the delay would be and the airport staff told them it hadn't taken off from KL yet (even though we are now told it had been missing for hours at that point). After that, I think the Crazies added to the story that it hadn't actually done the previous trip the day before from Beijing to KL so it couldn't have been in KL to start with.
They have not heard any since last tuesday, l really don't know what Houston has been waiting for, other than his obsession with debris.
I did see one expert say a plane hitting the surface could have compacted to the size of a bus, although l doubt if the wings would have well.
Which brings us back to debris. If it had compacted, wouldn't the wings have broken off thus leaving holes in the side of the fuselage for seat cushions, luggage etc to fling out?
Angus's obsession with debris might be because he's not sure if the plane really went in the water there either. We don't believe a lot of the duff info we are hearing, Angus is probably hearing a lot more even duffer info so I'm sure there's got to be quite a few doubters that really aren't believing the gospel according Hishammuddin.
I know [water] does strange things, but not that strange...
A major confounding factor in localising the pings is the SOFAR channel.
Quite a nice little video and article about it here, which also has this cautionary tale about the reliability of pingers:
"Paul-Henry Nargeolet has seen the Titanic close up, where it rests 12,500 feet under the sea. And he has taken an underwater expedition to search for wreckage of Air France Flight 447, which plunged into the Atlantic Ocean in 2009. Experience has taught him to doubt.
"I don't trust very much the acoustic," he says.
The retired French naval commander has undertaken dozens of dives in submersibles to the Titanic to secure its artifacts.
After putting them into baskets, his crew affixed locator pingers to them so he could swing back around to pick them up later, he told CNN's Don Lemon."Most of the time we never heard them, and we knew where they were," he said. He was only 1,000 - 2,000 feet away from his pingers."
(I really must try to get the hang of this new-fangled metric system! )
The pinger locator is towed at depth in order to get it as close as possible to the black boxes, but it's only a tiny little thing 28" x 38" x 18" with quoted outputs of "Unfiltered Hydrophone, Filtered Hydrophone Speaker, Headphones (x2)", so nothing like the sophistication of ship-borne (or even air-borne) sub-hunting equipment.
That CT comes from one of the relatives who were waiting at the airport to collect their family member. When there was no sign of the plane landing, they enquired how long the delay would be and the airport staff told them it hadn't taken off from KL yet (even though we are now told it had been missing for hours at that point). After that, I think the Crazies added to the story that it hadn't actually done the previous trip the day before from Beijing to KL so it couldn't have been in KL to start with.
Ah, the old "junior jobsworth who can't be a*sed finding out what's going on so fobs off someone who asks a question" basis for an entire conspiracy theory ... which then relies on everyone else (INMARSAT, ATC etc.) lying through their teeth, and on having several hundred people sitting around thinking "Hang on! We didn't get on/fly/refuel/load the plane! Oh well, no point in mentioning such a minor detail to anyone!"
^^ TBF the for all the guy knew the plane hadn't taken off! it hadn't entered Chinese air space or even that of Vietnam's, or least failed to contact VATC so as a general remark he was probably 99% of the time correct.
Due to the Pings received they have narrowed the search area to something like 5 by 7 KM
Do you have a link to that? I seem to have missed it.
In this morning's search plan for today, JACC stated that the sonobuoy search area (ping area) is now a 600 sq km square, which matches what Ocean Shield and Echo have been doing for the last few days. That's just under 25 km x 25 km, but of course they won't necessarily search all of that area with the Bluefin ROV.
Disappointingly, Marine Traffic haven't updated the positions of Toowoomba or Ocean Shield for over 8 hours now, so we don't know what they've been doing since we saw Toowoomba barrelling towards Ocean Shield at 23.2 knots early today. Echo is updated though and it's still zigzagging around doing its usual hydrographic thing.
Comments
Way up in the thread, we were told that the black-box locator beacons were only 'visible' within around a 6km range, and that was the limiting factor i.e. you had to be pretty much on top of the box, to detect it. Why is it that, now they have had supposed pings from the box, they still have a massive search area ?
Secondly, given that they have some fairly sophisticated sonar direction-finding equipment, why have they not been able to home in on the supposed pings that they have heard, rather than apparently being able to say nothing more definite than the fact it is in the sea, somewhere ?
Sound does strange things in water. There are thermal layers which can play havoc with acoustics, to such an extent that submarines can hide beneath the boundaries between one temperature and another.
The ping will also be radiating in all directions so if you detect a ping, all you can really say is that you're in range. It could be directly below or off to the side in any direction, and by any distance. That's why it's important to get as many contacts as possible, and for as long as possible. If you can hold a "ping" you can pootle along and listen for the signal getting stronger or weaker. Even then, when the signal is at is strongest, all you can say is that you've probably crossed a line on which the pinger may be lying.
Add in the fact that if the pinger is, for example, at the base of big rock formation, you might not be able to detect it from one direction as the rocks will mask the ping.
Due to the Pings received they have narrowed the search area to something like 5 by 7 KM
I know it does strange things, but not that strange...
(My 'area' is radar and electronic warfare, but it is pretty analogous to sonar)
At a basic level, if you have a bit of direction finding kit, it will have, let's say, 16 receivers sat in a circle. By analysing the relative signal strengths at each receiver, then you can work out pretty well where that signal is coming from. It'll be stronger (and earlier) on one side than the other, and that gives you your lead.
It may sound high-tech, but these navies have very high-tech kit. Imagine if you couldn't work out even vaguely where an enemy submarine was because 'sound does strange things in water'. In fact, the direction finding kit is usually set up to analyse very broad bands of signal frequencies, so the fact you are looking for just one makes it, theoretically, easier.
I'm sure they know what they're doing, but I'm wondering if they are on a bit of a wild goose chase again at the moment...
Ah, that's not 'so' bad. I was only half listening to the news and thought they were still in the thousands of sq.kilometres....
They have not heard any since last tuesday, l really don't know what Houston has been waiting for, other than his obsession with debris.
I did see one expert say a plane hitting the surface could have compacted to the size of a bus, although l doubt if the wings would have well.
Perhaps they're using higher tech kit than they're letting on.
I wonder if debris DID turn up in Diego Garcia, they would declare it, imagine the CT's going nuts.
Looks as though the Chinese have been using these.-
http://www.ebay.co.uk/itm/100m-LCD-Fish-Finder-Portable-Underwater-Sensor-Alarm-Transducer-Fishing-gift-/400692214456?pt=UK_SportingGoods_FishingAcces_RL&hash=item5d4b1dfab8
Might buy one to look for a bar of soap in the bath.
On a serious note they face a difficult job because of all the rubbish on the sea floor. About twenty years ago they thought they had found a Swissair fuselage only to find later it was a WW2 sub.
I'm not sure that the "looking for a submarine" analogy really works. They tend not to be 4,500 feet deep!
Increasing the distance by a factor of 4 or 5 is going to significantly increase the margin of error.
Going nuts? I thought they already were!
Bit slow, but is that the one about a photo from a colonscopy and used as proof of being at DG.
The question of debris (and anyone's "obsession" with it) is fairly irrelevant in terms of the underwater search. Identifiable debris would prove that the plane had crashed, but bearing in mind the extreme difficulty in back-predicting the ocean currents and winds, it wouldn't narrow the search area.
The only way of narrowing the search area was to listen for pings, and it would have been ridiculous not to allow a margin on the expected life of the batteries. After all, there's no immediate rush to map the floor. A few days isn't going to make any difference as the one thing we do know is that if the plane is down there, it isn't going anywhere!
Well, that's one of them!
I'm sure there are many more, but I kinda get bored of reading about HAARP and lizard-people! ;-)
There's a theory that the plane never existed, the people aren't missing at all
I'm not quite sure what the basis of that theory is
I'd suggest that isn't a conspiracy theory ... it's a conspiracy fantasy! As such, I think the "basis" is probably a fertile imagination, a degree of paranoia, and too much cheese before bedtime!
That CT comes from one of the relatives who were waiting at the airport to collect their family member. When there was no sign of the plane landing, they enquired how long the delay would be and the airport staff told them it hadn't taken off from KL yet (even though we are now told it had been missing for hours at that point). After that, I think the Crazies added to the story that it hadn't actually done the previous trip the day before from Beijing to KL so it couldn't have been in KL to start with.
Which brings us back to debris. If it had compacted, wouldn't the wings have broken off thus leaving holes in the side of the fuselage for seat cushions, luggage etc to fling out?
Angus's obsession with debris might be because he's not sure if the plane really went in the water there either. We don't believe a lot of the duff info we are hearing, Angus is probably hearing a lot more even duffer info so I'm sure there's got to be quite a few doubters that really aren't believing the gospel according Hishammuddin.
Quite a nice little video and article about it here, which also has this cautionary tale about the reliability of pingers:
"Paul-Henry Nargeolet has seen the Titanic close up, where it rests 12,500 feet under the sea. And he has taken an underwater expedition to search for wreckage of Air France Flight 447, which plunged into the Atlantic Ocean in 2009. Experience has taught him to doubt.
"I don't trust very much the acoustic," he says.
The retired French naval commander has undertaken dozens of dives in submersibles to the Titanic to secure its artifacts.
After putting them into baskets, his crew affixed locator pingers to them so he could swing back around to pick them up later, he told CNN's Don Lemon. "Most of the time we never heard them, and we knew where they were," he said. He was only 1,000 - 2,000 feet away from his pingers."
You are, of course, absolutely correct. :cool:
(I really must try to get the hang of this new-fangled metric system!
The pinger locator is towed at depth in order to get it as close as possible to the black boxes, but it's only a tiny little thing 28" x 38" x 18" with quoted outputs of "Unfiltered Hydrophone, Filtered Hydrophone Speaker, Headphones (x2)", so nothing like the sophistication of ship-borne (or even air-borne) sub-hunting equipment.
Ah, the old "junior jobsworth who can't be a*sed finding out what's going on so fobs off someone who asks a question" basis for an entire conspiracy theory ... which then relies on everyone else (INMARSAT, ATC etc.) lying through their teeth, and on having several hundred people sitting around thinking "Hang on! We didn't get on/fly/refuel/load the plane! Oh well, no point in mentioning such a minor detail to anyone!"
In other words, pretty short.
Do you have a link to that? I seem to have missed it.
In this morning's search plan for today, JACC stated that the sonobuoy search area (ping area) is now a 600 sq km square, which matches what Ocean Shield and Echo have been doing for the last few days. That's just under 25 km x 25 km, but of course they won't necessarily search all of that area with the Bluefin ROV.
Disappointingly, Marine Traffic haven't updated the positions of Toowoomba or Ocean Shield for over 8 hours now, so we don't know what they've been doing since we saw Toowoomba barrelling towards Ocean Shield at 23.2 knots early today. Echo is updated though and it's still zigzagging around doing its usual hydrographic thing.