Malaysian Airlines MH370 contact lost
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Underwater Locator Beacon Search
The AF447 report lists the effective range of the ULBs on the two recorders as 2 to 3 km. That's slant range, so if the water is deep, the hydrophones need to be lowered substantially, and of course good bathymetry (i.e., and underwater terrain map) helps a lot.
Main page for AF447 data:
FLIGHT AF 447
Sea Search Operations (31 MB):
http://www.bea.aero/fr/enquetes/vol....11.2012.en.pdf
"Both of the flight recorders of the aeroplane were equipped with a ULB designed to locate it when immersed. The duration of ULB transmission is at least thirty days from immersion(10). . . . As a rule, acoustic searches should always be preferred during the transmission time of the beacons. They are more effective than searches using sonar, magnetometers or video cameras.
The maximum range(11) of these beacons is of the order of 2,000 to 3,000 m. However, in the search area the average depth was 3,000 m. It was therefore necessary to bring the hydrophones(12) closer to the source of transmission, by towing specialized equipment nearer to the seabed.
(10)The regulatory minimum is 30 days, but the ULB manufacturer stated that the transmission duration was in reality of the order of forty days. This figure is determined by the capacity of the internal battery.
(11)It may be necessary to take into account the propagation of acoustic waves in a liquid medium, which depends on numerous interconnected parameters, such as the salinity and temperature of the water. When an acoustic wave is propagated in the sea, it is subject to refractions, which generate multiple trajectories. It can also happen that the acoustic waves are deflected in such a way that there is an area of shadow that is never reached by these waves.
(12)Undersea microphone. "
"The TPL20 and TPL40 systems are deep-towed devices belonging to the family of the “Towed Pinger Locators” manufactured by Phoenix International for the US Navy. The United States government made both the equipment and the associated operators freely available to the French government (17 people distributed on the two ships). In June 2009 the TPLs were the only systems capable of carrying out passive acoustic searches over large areas at significant depths.
The two TPLs are towed devices each equipped with an omni-directional hydrophone which can operate down to depths of six thousand metres with towing speeds ranging from 1.5 to 5 knots. They can be installed on all types of appropriate vessels capable of carrying a load weighing around 25 tonnes. A mapping software application uses GPS positioning information to follow the ship’s movements and the position of the towed device. The latter is equipped with a pressure sensor that permanently transmits the immersed device’s approximate depth of submersion. Management of the deployed cable length and ship towing speed is used to place the acoustic sensor at the required average submersion depth For example, an average submersion depth of 2,300 m for the TPL is achieved by deploying approximately 6,000 m of cable at a towing speed of 3 knots."
Much more interesting information in the report, such as description of an acoustic repeater that downconverts the 37.5 kHz signal to 12 kHz to be compatible with other sensors onboard a ship.
On using the French nuclear-powered submarine Emeraude:
"The Emeraude is equipped with numerous acoustic sensors including a sonar interceptor which was used during the search operations. This equipment was not originally designed to detect and localise ULB type acoustic beacons, but thanks to the optimisation of its settings and the use of additional computer software from 30 June 2009, its signal detection capabilities were enhanced."
"Deployment of the nuclear-powered submarine improved the search system and provided an interesting mobile device in terms of the surface areas covered (its average speed in the zone , between 6 and 10 kt, was higher than that of the other resources deployed). However its use proved difficult, given the safety constraints resulting from its integration in the search operations.
The presence of the nuclear-powered submarine meant that a vast safety zone had to be put in place around its patrol area in order to avoid any collision between the various pieces of towed equipment and the submarine. This permanent preoccupation with safety required delicate management of the undersea zones."
Interim report on search for ULBs:
Final report
"The first search phase aimed at detecting and locating the acoustic signals transmitted by the Underwater Locator Beacon (ULB) fitted on each flight recorder(8). As a priority, the aeroplane’s planned flight path as well as the greatest possible area inside the 40 NM circle was swept by two Towed Pinger Locators (TPL)(9).
No signal from either of the beacons was detected by the sensors deployed in the area despite TPL passing by, on two occasions, not far from the debris field, on 22 and 23 June 2009.
(8)There were two beacons on the A-330, one attached to the cockpit voice recorder (CVR) and the other to the flight data recorder (FDR).
(9)The two US Navy TPL’s are the only two towed hydrophones in the world able to operate to a depth of up to 6,000 metres."
Report on tests of similar ULBs:
http://www.bea.aero/fr/enquetes/vol....nt.09.2011.pdf
"Masked areas are present on the beacon’s vertical axis as well as the horizontal axis, leaving the possibility of significant of "shadow" zones. . . .
- It should be remembered that each time the level falls 6 dB(micro)Pa, the signal’s theoretical range falls by half. For beacons attached in this way on a flight recorder this can be very noticeably reduced, depending on orientation, in relation to the theoretical range of a single beacon."
Main page for AF447 data:
FLIGHT AF 447
Sea Search Operations (31 MB):
http://www.bea.aero/fr/enquetes/vol....11.2012.en.pdf
"Both of the flight recorders of the aeroplane were equipped with a ULB designed to locate it when immersed. The duration of ULB transmission is at least thirty days from immersion(10). . . . As a rule, acoustic searches should always be preferred during the transmission time of the beacons. They are more effective than searches using sonar, magnetometers or video cameras.
The maximum range(11) of these beacons is of the order of 2,000 to 3,000 m. However, in the search area the average depth was 3,000 m. It was therefore necessary to bring the hydrophones(12) closer to the source of transmission, by towing specialized equipment nearer to the seabed.
(10)The regulatory minimum is 30 days, but the ULB manufacturer stated that the transmission duration was in reality of the order of forty days. This figure is determined by the capacity of the internal battery.
(11)It may be necessary to take into account the propagation of acoustic waves in a liquid medium, which depends on numerous interconnected parameters, such as the salinity and temperature of the water. When an acoustic wave is propagated in the sea, it is subject to refractions, which generate multiple trajectories. It can also happen that the acoustic waves are deflected in such a way that there is an area of shadow that is never reached by these waves.
(12)Undersea microphone. "
"The TPL20 and TPL40 systems are deep-towed devices belonging to the family of the “Towed Pinger Locators” manufactured by Phoenix International for the US Navy. The United States government made both the equipment and the associated operators freely available to the French government (17 people distributed on the two ships). In June 2009 the TPLs were the only systems capable of carrying out passive acoustic searches over large areas at significant depths.
The two TPLs are towed devices each equipped with an omni-directional hydrophone which can operate down to depths of six thousand metres with towing speeds ranging from 1.5 to 5 knots. They can be installed on all types of appropriate vessels capable of carrying a load weighing around 25 tonnes. A mapping software application uses GPS positioning information to follow the ship’s movements and the position of the towed device. The latter is equipped with a pressure sensor that permanently transmits the immersed device’s approximate depth of submersion. Management of the deployed cable length and ship towing speed is used to place the acoustic sensor at the required average submersion depth For example, an average submersion depth of 2,300 m for the TPL is achieved by deploying approximately 6,000 m of cable at a towing speed of 3 knots."
Much more interesting information in the report, such as description of an acoustic repeater that downconverts the 37.5 kHz signal to 12 kHz to be compatible with other sensors onboard a ship.
On using the French nuclear-powered submarine Emeraude:
"The Emeraude is equipped with numerous acoustic sensors including a sonar interceptor which was used during the search operations. This equipment was not originally designed to detect and localise ULB type acoustic beacons, but thanks to the optimisation of its settings and the use of additional computer software from 30 June 2009, its signal detection capabilities were enhanced."
"Deployment of the nuclear-powered submarine improved the search system and provided an interesting mobile device in terms of the surface areas covered (its average speed in the zone , between 6 and 10 kt, was higher than that of the other resources deployed). However its use proved difficult, given the safety constraints resulting from its integration in the search operations.
The presence of the nuclear-powered submarine meant that a vast safety zone had to be put in place around its patrol area in order to avoid any collision between the various pieces of towed equipment and the submarine. This permanent preoccupation with safety required delicate management of the undersea zones."
Interim report on search for ULBs:
Final report
"The first search phase aimed at detecting and locating the acoustic signals transmitted by the Underwater Locator Beacon (ULB) fitted on each flight recorder(8). As a priority, the aeroplane’s planned flight path as well as the greatest possible area inside the 40 NM circle was swept by two Towed Pinger Locators (TPL)(9).
No signal from either of the beacons was detected by the sensors deployed in the area despite TPL passing by, on two occasions, not far from the debris field, on 22 and 23 June 2009.
(8)There were two beacons on the A-330, one attached to the cockpit voice recorder (CVR) and the other to the flight data recorder (FDR).
(9)The two US Navy TPL’s are the only two towed hydrophones in the world able to operate to a depth of up to 6,000 metres."
Report on tests of similar ULBs:
http://www.bea.aero/fr/enquetes/vol....nt.09.2011.pdf
"Masked areas are present on the beacon’s vertical axis as well as the horizontal axis, leaving the possibility of significant of "shadow" zones. . . .
- It should be remembered that each time the level falls 6 dB(micro)Pa, the signal’s theoretical range falls by half. For beacons attached in this way on a flight recorder this can be very noticeably reduced, depending on orientation, in relation to the theoretical range of a single beacon."
The CVR can't be "undeleted" or recovered because the data overwrites the previous in a circular buffer sort of arrangement. You can only recover data from a hard drive if it hasn't been written over with a new file.
Primary Radar -- Was Anybody Minding the Store?
We see a whole bunch of delay in hearing from the various militaries.
It sure looks to me that any primary echo data shared with the SAR effort has come from examining recordings.
The inference is that MH370 echoes did not get attention from anybody on a scope/display in Malaysia, Thailand, India, or Indonesia.
Were the folks watching scopes in Burma, China, Pakistan, Kazakhstan more on the ball?
It sure looks to me that any primary echo data shared with the SAR effort has come from examining recordings.
The inference is that MH370 echoes did not get attention from anybody on a scope/display in Malaysia, Thailand, India, or Indonesia.
Were the folks watching scopes in Burma, China, Pakistan, Kazakhstan more on the ball?
Last edited by RatherBeFlying; 20th Mar 2014 at 22:32.
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Fuel load
@Alchad
Earlier Bloomberg article quote:
"The Boeing 777 was carrying 49.1 metric tons (54.1 tons) of fuel when it departed Kuala Lumpur, for a total takeoff weight of 223.5 tons, according to Subang Jaya-based Malaysian Air."
Whether that is "normal" for the planned flight path I leave to the pilots who know these machines.....
Earlier Bloomberg article quote:
"The Boeing 777 was carrying 49.1 metric tons (54.1 tons) of fuel when it departed Kuala Lumpur, for a total takeoff weight of 223.5 tons, according to Subang Jaya-based Malaysian Air."
Whether that is "normal" for the planned flight path I leave to the pilots who know these machines.....
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This is a video from the RAAF Orion that shows a bit of footage
of the sea.
Missing plane: on board the search flight
of the sea.
Missing plane: on board the search flight
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glendalegoon
I THINK I heard the minister in a Malaysian press conference say that all the cabin crew were in a union, but not the pilots. Only just audible, and a rapidly swallowed aside.
Incidentally, I wish they had a radio mike to pass to questioners, or the chair would précis questions to the microphone. So annoying, and gives such a bad impression, to hear, again and again, the answer but not the question.
DOES ANYONE KNOW if malyasian air has a pilot's union? IFALP?
wondering why we haven't heard from them if they have one?
wondering why we haven't heard from them if they have one?
Incidentally, I wish they had a radio mike to pass to questioners, or the chair would précis questions to the microphone. So annoying, and gives such a bad impression, to hear, again and again, the answer but not the question.
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Yesterday the Transport Minister mentioned that they had received further radar data but that he was not at liberty to discuss it any further. IIRC a journo asked a question about that point, and the Transport Minister just repeated himself, and then added that 'also you have to understand that this data can be sensitive to the countries involved'. Does anybody have any theories as to where this data could be from? It was not mentioned by the TM today IIRC.
These countries do want to be anonymous due to several known reasons.
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glendalegoon
I THINK I heard the minister in a Malaysian press conference say that all the cabin crew were in a union, but not the pilots. Only just audible, and a rapidly swallowed aside.
Incidentally, I wish they had a radio mike to pass to questioners, or the chair would précis questions to the microphone. So annoying, and gives such a bad impression, to hear, again and again, the answer but not the question.
I THINK I heard the minister in a Malaysian press conference say that all the cabin crew were in a union, but not the pilots. Only just audible, and a rapidly swallowed aside.
Incidentally, I wish they had a radio mike to pass to questioners, or the chair would précis questions to the microphone. So annoying, and gives such a bad impression, to hear, again and again, the answer but not the question.
Not only a radio mike, would he stand where he does when he is making his speech, his voice goes so quiet when answering questions, 1/2 the time all you can hear is cameras firing away.
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KLN94
You can't, it seems, directly. They obscure it on purpose to prevent people picking and choosing and leaving coverage gaps. Maybe also to make clients pay who must choose.
There is a way to find where a map is, once you are looking at it.
This was posted here by some smart person whose name I have forgotten, sorry:
Incidentally, before anyone sneers at Tomnod, it is run by the very same Digital Globe company that supplied the images which are so central to the current Aussie search.
For all we know these very images were found by the crowd ! Probably not, though, the finder would be shrieking, and the publicity would be good for Tomnod, not just Digital Globe.
How can we access the Tomnod images of the area which may have been taken soon after the accident?
There is a way to find where a map is, once you are looking at it.
This was posted here by some smart person whose name I have forgotten, sorry:
Load a map at Tomnod
Change the word "challenge" in the url to "api". This brings up a page with the latitude & longitude on it which you can then google. You can then decide whether to search this area or select "Jump to random map" and start the process again
Change the word "challenge" in the url to "api". This brings up a page with the latitude & longitude on it which you can then google. You can then decide whether to search this area or select "Jump to random map" and start the process again
For all we know these very images were found by the crowd ! Probably not, though, the finder would be shrieking, and the publicity would be good for Tomnod, not just Digital Globe.
Someone asked why focused search near extreme end of the arc. I would say because this location fits with two hypotheses. 1. A deliberate plan to make the plane as hard to find as possible 2. Some mechanical problem and then the plane flew with autopilot until fuel exhausted (seems unlikely to me, but the location they are searching is consistent with this hypothesis).. Anywhere short of this location is arbitrary. It is also possible the pings were detected by a 2nd satellite, which would considerably narrow down the arcs.
We have been told that primary radar tracked something in the middle of the night. This was without any advance notice ie they did not really know what was happening. By the time if the last ping, it was morning and they knew they had a big problem. Every primary radar would have been looking hard. Surely this is the reason the central part of the arc was discounted. Could possibly be because the Pacific satellite didn't see the pings, but as Ana explained there are other reasons why pacific may not have seen. Indian seeing is more reliable than pacific not seeing. So I suspect more likely this area was discounted because they had lots of primary radar looking by time of last ping.
Still don't buy the theft theory. Too many variables, need other people involved, and probably couldn't set it up by the time you knew you had valuable cargo.
The only explanation making sense is that of someone who wanted to die, but wanted to disappear and for the world to never know where or why or how. Internally this individual was very rational - could not have managed this if irrational. But incomprehensible to others. There have been plenty of these throughout history.
We have been told that primary radar tracked something in the middle of the night. This was without any advance notice ie they did not really know what was happening. By the time if the last ping, it was morning and they knew they had a big problem. Every primary radar would have been looking hard. Surely this is the reason the central part of the arc was discounted. Could possibly be because the Pacific satellite didn't see the pings, but as Ana explained there are other reasons why pacific may not have seen. Indian seeing is more reliable than pacific not seeing. So I suspect more likely this area was discounted because they had lots of primary radar looking by time of last ping.
Still don't buy the theft theory. Too many variables, need other people involved, and probably couldn't set it up by the time you knew you had valuable cargo.
The only explanation making sense is that of someone who wanted to die, but wanted to disappear and for the world to never know where or why or how. Internally this individual was very rational - could not have managed this if irrational. But incomprehensible to others. There have been plenty of these throughout history.
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So, Greta, (fox news) is now going to explore the possibility that MH 370 could have made a successful water landing in the southern Indian ocean,
just like Sully did in the Hudson.
right Greta, why not fly 7 hours to the open ocean to attempt yr tricky water landing. Lucky for us. She has a NTSB expert who doesnt expect that theory would occupy much of the sar peoples time.
greta points out the the cvr "keeps looping every two hours" so, she figers, we arent going to get much......apparently greta expects all we will hear off it is, glug, glug, glug...
thankfully after this " breaking news" analysis, greta is moving on to a discussion of the olympic ice dance team: putin and obama.
just like Sully did in the Hudson.
right Greta, why not fly 7 hours to the open ocean to attempt yr tricky water landing. Lucky for us. She has a NTSB expert who doesnt expect that theory would occupy much of the sar peoples time.
greta points out the the cvr "keeps looping every two hours" so, she figers, we arent going to get much......apparently greta expects all we will hear off it is, glug, glug, glug...
thankfully after this " breaking news" analysis, greta is moving on to a discussion of the olympic ice dance team: putin and obama.
Nemo Me Impune Lacessit
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Regarding radar coverage, either military or civil, you can bet your bottom dollar that Singapore would have information that they would not make public, ever.
SLFplatine asked about FDR/CVR being ejectable, yes of course they can and Martin Baker, if asked would be happy to produce a unit that under pre set conditions would eject from the aircraft and float. Now the problems, it would have to be a removable self contained unit as regulatory authorities would require a function test now and then, so spare units would be needed and a test rig would be needed, (possibly run by MB), the zeros behind the $ sign just get longer! A unit located in the horizontal stabilizer, designed to eject at an angle, so avoiding fouling the sinking wreckage, which may, by now, be inverted, should suffice, these days many of the electronic boxes are connected via multi pin bayonet type connectors and secured by conventional means to prevent the unit vibrating or being shaken out, back to Martin Baker who specialise in perfecting systems where conventional securing can be breached when required.
Short answer, yes, an ejectable and floating CVR/FDR is quite feasible.
SLFplatine asked about FDR/CVR being ejectable, yes of course they can and Martin Baker, if asked would be happy to produce a unit that under pre set conditions would eject from the aircraft and float. Now the problems, it would have to be a removable self contained unit as regulatory authorities would require a function test now and then, so spare units would be needed and a test rig would be needed, (possibly run by MB), the zeros behind the $ sign just get longer! A unit located in the horizontal stabilizer, designed to eject at an angle, so avoiding fouling the sinking wreckage, which may, by now, be inverted, should suffice, these days many of the electronic boxes are connected via multi pin bayonet type connectors and secured by conventional means to prevent the unit vibrating or being shaken out, back to Martin Baker who specialise in perfecting systems where conventional securing can be breached when required.
Short answer, yes, an ejectable and floating CVR/FDR is quite feasible.
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AF447 beacon again
It seems necessary to specify:
one of the ULB (FDR) was not found (dolphin/shark/ E.T /other).
The second one (recovered) was out of duty.
BEA declared the CVR ULB (S/N ST24703)
[cvr.ulb.examination.report]
one of the ULB (FDR) was not found (dolphin/shark/ E.T /other).
The second one (recovered) was out of duty.
BEA declared the CVR ULB (S/N ST24703)
" was thus considered as not functional ".
Last edited by NeoFit; 21st Mar 2014 at 10:57. Reason: Link addition
Flash memory wears out with use, just as you said. Use being read/write cycles. In the case of a 120GB drive being used as described above a read/write cycle is only going to happen once every 2000 hours. Combine this with the fact that "Most commercially available flash products are guaranteed to withstand around 100,000 P/E cycles before the wear begins to deteriorate the integrity of the storage". Once again doing the math 2000 hours per cycle by 100,000 cycles is about a 200 million hour lifespan of continuous use. 24 hours/day, 365 days per year...so that is somewhere north of 22 thousand years!
Number of channels ................. 4
Impact tolerance ...................... 3400 Gs /6.5ms
Fire resistance .......................... 1100 deg C /30 min
Water pressure resistance ........ submerged 20,000 ft <<< 8900 psi
That's just the executive summary.