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AF 447 Search to resume

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AF 447 Search to resume

Old 2nd Aug 2010, 11:45
  #1821 (permalink)  
 
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No reason to doubt

the French nation, same as the UK or US, won't want to turn it's back on its citizens
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Old 2nd Aug 2010, 13:16
  #1822 (permalink)  
 
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No reason to doubt.

The French transport minister has been quoted saying that he will wait until receiving a BEA report in early September before making a decision.

iafrica.com | travel | flights <i>Another</i> search for AF447?
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Old 2nd Aug 2010, 22:22
  #1823 (permalink)  
 
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AF crew also in dark...

Spoke to a crew member on an AF flight from Rio to Paris this week and they don't seem to know any more than the general public.

There is apparently little info coming from AF and crew get what little they know from the media.

Had hoped for some kind of insight but this is not unexpected in the circumstances I guess...

Jim
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Old 4th Aug 2010, 01:27
  #1824 (permalink)  
 
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JD-EE said:
Bearfoil (re 1810), satellite radios don't work every time.

...

Worst of all, satellites are not there when you need them. If your first awareness of a problem is the plane falls off on a wing in a massive stall - and ACARS goes off beam to the satellite. Worst yet, you are about mid way on a route between Perth and any place in South America - you are over the South Pole. You have no satellites to speak with.
I am sure that you know more of this than I do however I think that you are perhaps exagerating the issues.

1.
I understand that Irridium works all over the globe without dead spots and can work with small hand held battery powered phones and omni antennas. With the resources available on an airliner surely there is no problem at all to phone home with at least positional information every few seconds. I would imagine that it would work for a very large proportion of the time.

2.
I would be surprised if phased array antennas were not available for non-irridium satellite work. These can be steered I would guess pretty much instantly. The technology exists to track and shoot down artillery shells and other more sophisticated missiles, I cannot believe that tracking a geostationary satellite from an aeroplane is beyond us.


All this reminds me of the landing gear weight sensor discussion. The technology was done and dusted decades ago, but for some reason there seems to be a flux of dissent explaining why it is too difficult or impractical.
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Old 4th Aug 2010, 09:20
  #1825 (permalink)  
 
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jimjim1 wrote:-

With the resources available on an airliner surely there is no problem at all to phone home with at least positional information every few seconds.
The technology is available and in place on many fleets. However, cost is still a huge problem, and the "every few seconds"option would currently not be considered commercially viable.
I would be surprised if phased array antennas were not available for non-irridium satellite work.
Phased arrays are commonly in use and can be used for both geostationary and low earth orbiting (sun synchronous) satellites.

In summary, the following non ATC position reporting and emergency beacon systems are available.
  1. AOC/ACARS via VHF or Satellite.
  2. Use ADS-B 1090MHz broadcast position data.
  3. Monitoring of 406.025MHz ELT/EPIRB transmissions -
(a) By Geostationary satellites - GEOSAR,
(b) and Low Earth Orbiting satellites - LEOSAR
With reference to (1), AF447 was sending a basic AOC position report every 10 minutes to AF Operations/Maintenance by a commercial data link through a geostationary satellite. This same link provided the ACARS maintenance messages.

There are currently no geostationary satellites equipped with an ADS-B 1090MHz receive and forward package, as would be required for (2) to be of use in oceanic FIRs. Localized monitoring of ADS-B transmissions can and is made by suitably equipped ground stations subject to the aircraft being fitted with the mode. Reception range is dependent on the height of the aircraft and a suitable horizon at the receiving antenna. This is obviously not suitable for use in oceanic FIRs.

Emergency beacon transmissions (3) on 406.025MHz are monitored by a number of Geostationary (GEOSAR) and Low Earth Orbiting (LEOSAR) satellites operating as the Cospas-Sarsat international satellite-based search and rescue (SAR) distress alert detection and information distribution system.

Beacons detected by GEOSAR, provided they are transmitting position coordinates, can have SAR resources deployed quickly to their position. Beacons that do not transmit position coordinates will eventually be heard by a passing LEOSAR satellite and doppler shift techniques are used to establish that beacon's position.

NOTES::
  • The LEOSAR system does have "holes" in its coverage - due to a lack of Local User Terminals in some remote parts of the globe. The southern polar regions are a notable void space.
  • The GEOSAR system coverage is limited to latitudes of 70 degrees and less.
Any 121.5MHz signals emitted by the ELT/EPIRBs are no longer detected by satellite, but the signal is still used by ships/aircraft and land means to home in on the beacon.

But back to position reports. The most cost effective solution for fleets operating over oceanic FIRs is to implement a more frequent position reporting regime using the existing AOC/ACARS protocols. The costs will increase proportionately, but the costs of not doing so can be equated to those incurred in the search for AF447. The cost of the former as opposed to the later are minor in the extreme.

mm43

Last edited by mm43; 4th Aug 2010 at 19:49. Reason: typo
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Old 4th Aug 2010, 12:33
  #1826 (permalink)  
 
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That P2P solution - Pragmatics and Practicality

The post by the Shadow at #1782 suggested a mutually supportive P2P solution for flight recorder data transmission, gathering - and collation as required. I ran that proposal past my #2 son who's a very accomplished software programmer and he said "sure thing"! / "easy peasy". He maintains that it's quite a straightforward proposition, even if accomplished via HF USB. Data collection volumes only become a problem if an incident occurs and all aircraft comprising the "ships that passed that night" need to upload (data-dump) to a centralized facility. That might be accomplished by swapping out hard disks post-flight - so that aircraft never fly subsequent flights with the same HD fitted as on the prior (incident coincident) flight. The regos of those "ships that passed that night" could be determined and denominated via a data-block on the flight-plan..... and the airline/air force's ops dept asked to upload their aircraft's data.

In addition he suggested that receivers could be placed onboard selected naval and merchant vessels to help fill in the coverage holes in very remote areas.... if it was determined that accessing data from moored and solar-powered marine buoys would be too hard. You could even position one of the new solar -powered high altitude blimps astride the prominent dead-zones.

The challenge of piecing together piecemeal collected and distributed data was solved by P2P almost 15 years ago - and by NASA well before that. The need for expensive uploading to (or bouncing data off) the Iridium satellites constellation need not be a deterrent for inflight data gathering. In fact, if you wished, one of the next Moon missions could station a solar-powered telemetry unit on the lunar surface to intercept much of the transmitted traffic.... and retransmit it on request/as required.

The alternative to repetitive fruitless and futile expensive searches such as that for AF447 answers has generated will probably prove not to be as technologically challenging as everyone is making out.... i.e. cloud computing data collection is a proven capability. But it would appear to be the case now (and I tend to agree) that NOT finding a bottom line for AF447 will be quite unacceptable to all concerned..... yet that is presently the probable outcome. That's the message that seems now to be coming from many different directions. Beyond the "flight safety unknowns" context, it's quite unfair to all concerned, victims and their families included.

Has anybody found a valid conceptual flaw in the concept?
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Old 4th Aug 2010, 16:12
  #1827 (permalink)  
 
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Flaws in : That P2P solution - Pragmatics and Practicality

WWW asks:
Has anybody found a valid conceptual flaw in the concept?
A very basic bandwidth problem:
From post 1728
aircraft broadcasts the DFDR/CVR data on VHF/FM
1: VHF/FM channels are sized to carry one voice channel with some accepted loss of quality. Not sure how 3 or 4 CVR channels plus the DFDR data will fit in that same bandwidth. Note that the CVR often takes extensive processing to extract the transcript, further degrading the audio quality by compressing to fit in the proposed BW would make it unusable in at least some cases.

2: "BROADCASTS", what happens when there are multiple planes within range of each other, coordinating the channels used for this broadcast without interfering with normal use would be challenging at best.

Last edited by MurphyWasRight; 4th Aug 2010 at 16:13. Reason: Typo in title
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Old 4th Aug 2010, 17:40
  #1828 (permalink)  
 
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On the MOON???

Er, WeeWinkyWillie's #2 son needs to look into a transmission mode known as "Moon Bounce" to get an idea of the path loss between the Earth and the Moon. He also needs to look into "The Dark Side Of The Moon". Too often people think of that as the face away from the Earth. T'aint so, McGee. The dark side of the Moon is the side facing away from the Sun. So any transponder on the Moon would have to be passive, have a 14+ day battery pack, or else be carefully sited on a mountain peak very near one of the Moon's poles. And this has to be done in an era when we cannot repeat what a certain now 80 year old gentleman did on July 20th 1969. So servicing such a unit (batteries die) or installing such a unit at one of the poles would be a major undertaking.

My understanding is that the Iridium satellites are pretty heavily loaded at present, usually by government agencies, usually with undisclosed names. That is, however, one of the very few global coverages that exists.

Buoys need to be sited every 100 miles or so all over the globe. That would include portions of the globe in 24 hour darkness during major portions of the year. I did indeed play with Google Earth a little to discover that the routes, Perth to South America, all feature at least some time over the Antarctic ice sheet. Coverage down there would require something fancy to get through the winter, or else satellite coverage that would have to be dedicated to this purpose 24x7 lest it be preoccupied with other traffic when a plane has problems. <shrug> It can be done. How much would a dedicated data dump channel on Iridium cost per year? Maybe it's worth the cost.

Another thing that concerns me comes from my college days in the Detroit area. I was a ham radio operator. And I worked aurora bounce around the country when we had some good (lamentably at the time rare) auroras. This was on 50Mhz. I was told at the time it also affected the 144 MHz ham band. Flying through the area under the aurora is probably a radio numbing experience for most any frequency.I wonder if anybody has performed this experiment. What frequency would be needed to penetrate the murk? Fortunately, the contrived bit of my scenario is presuming a plane would have trouble in that area. At a guess the weather at aircraft altitudes is pretty benign over the poles. Any corrections to my guess?

Last edited by JD-EE; 4th Aug 2010 at 21:16. Reason: Fixed fingers getting ahead of typing: The dark side of the Moon is the side facing away from the Sun.
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Old 4th Aug 2010, 18:35
  #1829 (permalink)  
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The "problem", as I see it is to cover areas where there is a risk of being unable to retrieve the recorders, an extremely scant probability. Coverage could be extremely limited to those regions that are historically difficult for data transmission. 447 was effectively out of range, an "acceptable" parameter that needn't occur at all, in my opinion. All flights over land, and most of the Oceans, present high probabilities of retrieval of the recorders.

That ACARS was successful (and disseminated), is a case in point. Simply because the data encapsulated in the company channel speaks to a possibility of capturing accident information, that would seem to be a starting point.

Four minutes of the final entry into this a/c "diary" was directed to maintenance issues. Fine. Even this information very nearly solves the riddle without the flight recorders. Linking this channel's ennable via transponder mayday code could disable the maintenance flow, and substitute flight controls data, loads, EPR's, etc. This would be seemingly at pilot's discretion, but flipping the character of the data from saving some Mx money to transmitting the a/c's information in an emergency (certainly to include GPS fixes) seems a valid deal to me.

We are talking about a miniscule vulnerability to Radio isolation compared to system wide needs, certainly this could be done at reasonable expense?

bear
 
Old 4th Aug 2010, 19:40
  #1830 (permalink)  
 
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Hi,

The alternative to repetitive fruitless and futile expensive searches such as that for AF447
Less than 20.000.000 so far .....
It's not yet expensive in regard of the cost of the researched object (+ - 250.000.000) and the possible reward for the victims relatives and safety if the black boxes or parts of the airplane are found ....
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Old 4th Aug 2010, 21:15
  #1831 (permalink)  
 
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Originally Posted by JD-EE View Post
...He also needs to look into "The Dark Side Of The Moon". Too often people think of that as the face away from the Earth. T'aint so, McGee. The dark side of the Moon is the side facing away from the Earth.
Er...it's the side facing away from the sun. I'm pretty sure that's what you really meant...
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Old 4th Aug 2010, 21:34
  #1832 (permalink)  
 
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AF447: A lawyer wants to sue the French State

A German lawyer representing German and Chinese families of victims of the Air France disaster Rio-Paris flight, which resulted in 228 deaths last year, on Wednesday blamed responsibility for the accident on the French state.

Ulrich von Jeinsen told AFP he intends to file a complaint "against unidentified persons of the French state" which he has said were guilty of not establishing a register of incidents involving speed probes (Pitot), as requested by a European Commission directive dating from 2003.

"Because of this lack of European standards, it is possible that the French government was not aware of 30 incidents involving the freezing of similar instruments for measuring speed at high altitude," according to the firm of Mr. Jeinsen Neu-Anspach, near Frankfurt.

The Office of Investigations and Analysis (BEA), responsible for the technical investigation, believes that the failure of the pitot probes measuring speed is a possible factor in the catastrophe of June 1, 2009 in the [South sic.] Equatorial North Atlantic.

Dr. von Jeinsen wants the judge handling the matter to broaden the scope of his investigation to determine the responsibilities of representatives of the French state.

Le Figaro - AF447: un avocat veut poursuivre l'État

---------------

None of this is going to go anywhere, or go away until the wreckage is found.

mm43
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Old 5th Aug 2010, 01:52
  #1833 (permalink)  
 
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Color me for letting fingers type what the wanted instead of what my brain wanted.
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Old 5th Aug 2010, 08:50
  #1834 (permalink)  
 
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The radio-relay of data over remote areas

The radio-relay of data over remote areas could be provided by a Zephyr unmanned and autonomous drone. They can stay on-station for many months at a time at altitudes in excess of 75,000 feet.
It's operational now.
.
see link
.

Air to air range 35,000ft to 75,000ft ??

Anyone??
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Old 5th Aug 2010, 09:31
  #1835 (permalink)  
 
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Originally Posted by TheShadow View Post
The radio-relay of data over remote areas could be provided by a Zephyr unmanned and autonomous drone. They can stay on-station for many months at a time at altitudes in excess of 75,000 feet.
It's operational now.
.
Anyone??
70,000 is during the day with the sun shining. It loses about 20,000ft overnight.

I wouldn't fancy its chances in the sort of weather 447 went through, and good luck finding any bits of it afterwards.
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Old 6th Aug 2010, 02:24
  #1836 (permalink)  
 
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Subsequent to the AF447 accident, and as a result of it, the BEA formed the Flight Data Recovery Working Group to undertake a technical evaluation of how improvements could be made to all aspects of recovering flight data including in-flight transmissions, storage, position reporting, along with a float-free ELT/EPIRB and ULB frequency & operating period changes.

http://www.bea.aero/en/enquetes/flig...nal.report.pdf

The group was composed of more than 120 members from numerous countries, representing a wide range of actors: investigation bodies (BEA, NTSB, AAIB, TSB, BFU…), regulatory authorities (ICAO, EASA, FAA…), airframe manufacturers (Airbus, Boeing), recorder manufacturers (L3Com, Honeywell, GE, DRS, EADS...), ULB manufacturers (Dukane, Benthos), airlines (Air France, Fedex), satellite manufacturers and service providers (Astrium, Inmarsat, iridium, SITA…), international associations (IATA, IFALPA). This allowed the compilation of comprehensive studies on all the items.
The most cost effective and deployable improvements are listed below:-
  • Triggered transmission of flight data when an upcoming catastrophic event is detected, but only for aircraft already equipped with SatCom and transmission of a subset of the FDR data (essential parameters or at least latitude, longitude and altitude). However, trigger conditions to define an emergency is not mature yet by industry standards, even though testing has been underway for several years making this approach to streaming data more robust.
  • Include parameters (position, heading, speed, altitude, accelerations…) in ACARS messages, but only for aircraft already equipped with ACARS.
  • Installation of an ED-112 combined deployable and free-floating flight recorder+ELT, but for new type certificate aircraft only.
  • Increased autonomy of ULBs (90 days instead of 30 days)
  • Use of a lower frequency for ULBs attached to the aircraft.
The priority attached to solutions that stemmed from this evaluation were:-
  1. Extended duration of emission of the ULB attached to the flight recorders (90 days instead of 30 days),
  2. Installation of low frequency ULB (between 8.5 and 9.5 kHz) attached to the plane,
  3. Regular transmission of basic aircraft parameters (via ACARS for example),
  4. Triggered transmission of flight data. On this point, additional work is deemed necessary and the BEA will again consult members of the group to conduct a study,
  5. Installation of deployable recorders.
Unmanned and autonomous drones didn't even get a mention. Seems to me that they are the expensive toys of the military and spy agencies.

ADS-B was the next item on the list, but due to the infrastructure needing to be created, i.e. satellite based receive and forward hardware, this too is currently in the long-term basket.

mm43
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Old 7th Aug 2010, 05:20
  #1837 (permalink)  
 
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TheShadow asks:
"Air to air range 35,000ft to 75,000ft ??"

All other things being optimal it's about 600 miles at 50,000 each end. It would go up another 100 to 150 miles or so if one end was at 75,000'. The distance to a tangent to the earth line of sight is roughly D = sqrt(2*h), where D is in miles and h is in feet. The limiting distance is found by Dt = sqrt(2*h1) + sqrt(2*h2).

As you approach that limiting distance you get some strange effects often called "picket fencing" as the signal and its bounce off the Earth constructively and destructively compete with each other.

That's academic since the range goes to about 300 miles at night at the South Pole in the Northern Summer and the Zephyr becomes Zephyr a glider and then a static object on the surface. You MIGHT get away with near continuous coverage if the Zephyr could be programmed to stay 500 miles North of the pole and follow the tiny patch of Sun it might find. I'm not sure that would be enough Sun to keep it up there with the very oblique angle of the Sun's light on its solar cells.
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Old 7th Aug 2010, 05:56
  #1838 (permalink)  
 
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Bearing in mind the limited width of the ITCZ in the area of AF447's demise, and given the considerable range (air to air) for a high altitude loitering Zephyr drone, it should be possible to keep the drone out of any nasty weather's harm's way (see below). For polar duty, the "out of season" lack of insolation could well be a downing discrepancy for any solar-powered winged beastie. So for high latitude on station polar radio-relay duties, a helium-filled solar-powered (and -thrusted) blimp may prove to be a better solution. This one see link is capable of months on blimp-station at 60,000ft. Its solar panels can be on its sides.
.
The ITCZ is a region of light winds, which lends it the name the doldrums. The convergence of the Southeast and Northeast Trade Winds, within the doldrums, creates a zone of Cumulus clouds and attendant shower activity. Cumulus clouds often build up to great heights. Aircraft reports have estimated tops of Cumulonimbus to be as high as 12,000 m. The ITCZ varies from 20 miles to as much as 300 miles in width, and typically has an undulating conformation.
.
Seasonal Meandering of the ITCZ. We are interested in the ITCZ because, under certain circumstances, tropical depressions on the ITCZ intensify to hurricanes. It may seem puzzling that the ITCZ can produce cyclones, when the Coriolis force is at its weakest near the equator. The answer to this puzzle lies in the fact that the ITCZ is not stationary on the equator, but migrates north and south with the seasons. The ITCZ moves north during the high-sun season of the Northern Hemisphere, and south during the high-sun season in the Southern Hemisphere. These movements are not perfectly symmetrical above and below the equator, because of the influence of land masses, among other factors.


.
from this link
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Old 7th Aug 2010, 06:25
  #1839 (permalink)  
 
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Everybody talking at once......avoiding that annoying superheterodyne squeal

Murphywasright addressed the problem of mutual interference if aircraft were to be broadcasting their data on the one V/UHF frequency. This has been resolved within "link" technology. i.e. no mutual interference. I imagine that it utilizes the same (or basically similar) handshaking protocols used to avoid interference/data collisions on the internet's pipes.
TADIL-A/Link 11 is a secure half-duplex TADIL radio link used by NATO that receives or transmits--but not both simultaneously--a sequential data exchange digital link. It exchanges digital information among multiple airborne, land-based, and ship-board data systems. It is the primary means for exchange of complex changing data such as radar-tracking information beyond line of sight. TADIL-A can be used on either high frequency (HF) or ultrahigh frequency (UHF). However, the U.S. Army uses only HF.
Link 11 will be replaced by Link 22.
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Old 8th Aug 2010, 00:14
  #1840 (permalink)  
 
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Bearfoil wrote in Post #1831

That ACARS was successful (and disseminated), is a case in point. Simply because the data encapsulated in the company channel speaks to a possibility of capturing accident information, that would seem to be a starting point.
In principle you are right. The problem is that the ACARS transmission uses low speed data rates and consequently occupies a narrow bandwidth channel. You will have noted that each ACARS message took on average 6 seconds from initiating until the receipt confirmation was received. A different data protocol and more bandwidth would be required to transfer meaningful amounts of flight parameters even in an emergency situation.

Basic GPS data including position and altitude sent every 10 seconds with the remaining unused period in each 10 second interval used for selected flight parameters would be of use. It should be remembered that the position data is already being broadcast (by most aircraft) on ADS-B, and if means can be found for receiving and recording that data, then the ACARS channels flight data upload can be increased proportionately.

I am not against the promotion of various alternate means to get all or some of this information from flights over oceanic areas, but I am mindful of the BEA's Flight Data Recovery Working Group, and the expertise they accumulated for that project. Change happens slowly, especially when the infrastructure doesn't exist, or where industry standards/protocols need to be changed and approved by statutory authorities.

mm43
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