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AF 447 Search to resume

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AF 447 Search to resume

Old 9th Nov 2009, 20:20
  #21 (permalink)  
 
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Why not have floating black boxes? After all a lot of the lightweight stuff did float up to the surface.
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Old 9th Nov 2009, 20:22
  #22 (permalink)  
 
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Originally Posted by fflyingdog View Post
Why do we still need CVRs and FDRs as pyhisical boxes onboard the aircraft ? Perhaps we should be looking at a better form of data recovery,would it not be possible in these high tech days to be able to fit a permanent satellite uplink from each aircraft.....
This was already discussed elsewhere on PPRuNe, somebody can probably post a link.
Two issues...
- The huge amount of (expensive) bandwidth needed to transmit/receive/process 99.999% useless data,
- The simple fact, that in extreme occurrences such as AF447, your "permanent" satellite uplink would already have been interrupted by an extreme aircraft attitude, total power failure, fire, explosive decompression destroying the sattelite aerial and wiring, etc. ... and the final few seconds/minutes of data would never be transmitted....

CJ
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Old 9th Nov 2009, 20:34
  #23 (permalink)  
 
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I agree that maybe the final few seconds in some instances data may lost because of aircraft break up loss of electrical power (although easily solved with built in power supply),But on the other hand the possibility remains that the ground based computer may have spotted a trend or some such and been able to avert an incident before it was critical. Bandwidh may be expensive but in real terms, the possible preventative safety issue should be paramount .
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Old 9th Nov 2009, 20:39
  #24 (permalink)  
 
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HamishMcBush, thanks for a lot for your link.
Originally Posted by HamishMcBush View Post
So far 28 days has proved adequate on all but a handful of occasions.
This was obviously one of those occasions....

All I can say... I wish the newly announced search effort all the best of luck

CJ
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Old 9th Nov 2009, 20:48
  #25 (permalink)  
 
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Here is what I don't understand. The French had submarines looking for the wreckage, right? Submarines have all this high tech sonar systems designed to hunt for other subs. There is a black box, transmitting a ping out there, saying "find me", and they can't locate it?

Doesn't make any sense. They can find submarines that are trying not to be found, yet they can't locate a box that is begging to be found.
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Old 9th Nov 2009, 20:51
  #26 (permalink)  
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ChristiaanJ
I explained data streaming ( continuous down linking via Iridium satellites of aircraft parameters ) in some post in the original AF447 thread .

Details can be found at AeroMechanical Services Ltd. - afirs Up Time

The system already is in place but mainly for VIP jets as it is expensive indeed.
Also , as you very correctly pointed out, the last seconds , possibly even the last minute, would probably be missing in our case.

Another idea would be to have a small amount of radioactive material being released inside the recorders after a certain depth ( say 1000m or so ) enabling some military sensors to detect the anomaly and the location. Not sure of the accuracy of those sensors though. Possibly something for the future.

As to the duration of the "PINGS " I was told they weaken with time , but still can be read after a very, very long time. Much longer than 28 days.
The recorders of the KAL o7 B747 shot down over Sakhalin island was retrieved by the Russian Navy more than a year after its demise.
But they were not laying down at 4000m .
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Old 9th Nov 2009, 21:11
  #27 (permalink)  
 
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Can they even be sure the boxes can survive the extreme water pressures at those depths? Something in the order of several tons per sq inch trying to crush it
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Old 9th Nov 2009, 21:17
  #28 (permalink)  
 
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It would seem that the dustman has swept through the thread and performed some cleaning.

I'll have to say, there are some reasonable posts here. Most of these thoughts were addressed in the long-running AF447 thread, but that said, good dialogue so far.

Regarding "bursts or real time data transmission, ChristianJ summed it up well.

I would also suggest that HamishMcBush's post tells a lot of the story.

Specifically.....

I am lead to believe that it is most likely to be the undersea terrain that has caused issues with finding AF447, with resemblance to underwater Alps.
Regards to all,
11Fan
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Old 9th Nov 2009, 21:45
  #29 (permalink)  
 
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Perhaps the delay until Feb. is due the depth of the thermocline in the search area? The more shallow the thermocline, the less costly it would be to get a submarine or listening device beneath it.
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Old 9th Nov 2009, 22:08
  #30 (permalink)  
 
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Originally Posted by ATC Watcher View Post
ChristiaanJ
I explained data streaming (continuous down linking via Iridium satellites of aircraft parameters ) in some post in the original AF447 thread .
Details can be found at AeroMechanical Services Ltd. - afirs Up Time
Quoting from that site:
"The afirs unit is an avionics component that resides on the aircraft. The afirs unit monitors the various systems on the aircraft, and when certain events are detected information is transmitted via Iridium satellite."
When certain events occur....... is the key.
Very much like the ACARS messages from flight AF447.

The continuous data stream into the FDR includes far, far more parameters, llike attitude (all axes), airspeed, engine parameters, control surface positions, etc., sampled every few seconds, sometimes even more often.
It's way, way beyond what could be transmitted via a satellite link, or stored and managed at the receiving end, for the tens of thousands of commercial flights in the air at any one time.

Another idea would be to have a small amount of radioactive material being released inside the recorders after a certain depth ( say 1000m or so ) enabling some military sensors to detect the anomaly and the location. Not sure of the accuracy of those sensors though. Possibly something for the future.
Same difference....
As with djp's excellent idea, it's not in place.
And with accidents as that of AF447 being extremely rare, it's highly unlikely there will ever be any 'rule-making' about making it mandatory.

CJ
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Old 9th Nov 2009, 22:13
  #31 (permalink)  
 
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Originally Posted by vovachan View Post
Can they even be sure the boxes can survive the extreme water pressures at those depths? Something in the order of several tons per sq inch trying to crush it
Good question.
I'm not sure what type of recording system was used in that A330's FDR.
But if it was any kind of solid-state memory recording, it might crush the boxes, but not the memory chips.

CJ
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Old 9th Nov 2009, 22:14
  #32 (permalink)  
 
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On pinger life, this website says that Dukane, the locator beacon's battery manufacturer reports battery life drops of significantly after 30 days.

Dukane, the AF447 pinger manufacturer, has confirmed that the pingers may only last a day or so longer than the specified thirty days. Unlike regular flashlight batteries that fade out slowly, the battery technology used in the pingers will hold its voltage for the thirty days, and then quickly collapse along with the transmitted signal.
On underwater search methods, the same site explains how an untethered Automated Underwater Vehicle (AUV) was evaluated to search for AF447's locator beacon.

Like the unmanned drone aircraft used by the military, AUVs are unmanned, untethered, computer controlled underwater vehicles. C & C's 4,500 meter rated vehicle is capable of searching large areas while flying at a constant height off the ocean bottom at four knots for two days at a time before returning to the surface to refuel.
Here is an interesting whitepaper, discussing how the Ark Royal was found, etc. (note: link downloads a .pdf file).
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Old 9th Nov 2009, 22:37
  #33 (permalink)  
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ChristianJ;
The continuous data stream into the FDR includes far, far more parameters
Depending upon the data frame programming, up to 40,000 parameters are available on later types but realistically, between 2000 and 3000 parameters can be done in a FOQA Program. DFDRs typically capture between 300 and 1000 parameters at varying sample rates. QARs, (optical disc, PCMCIA card etc) will almost always have higher sampling rates than DFDRs which for some parameters, ('g', control stick position etc) increases the usefulness - just like a strobe-light going off at ten times a second is more useful in a dark room than once every 4 seconds...QED.

I am aware from others' contributions of some technologies which can transmit such data on available satellite bandwidths which have been touted as "cost effective". Trouble is, I haven't seen the boxes and I have already commented on the Aeromechanical Services solution on the Tech Log thread. The security of the data is paramount and so far, no one advancing these "solutions" has broached or discussed the topic.

PJ2
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Old 9th Nov 2009, 23:30
  #34 (permalink)  
 
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I understand that military transports can deploy floating recorders.

Cheers,


Dick
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Old 9th Nov 2009, 23:47
  #35 (permalink)  
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Dick, others offering thoughts on this kind of solution;

"Deploying the recorders" is a variation on the solution (squirting out selected parameters as per the Aeromechanical model), which also relies upon the triggering of a "mission threatening event". How is that "event" or series of events defined? How would false alarms be prevented while still sending out the last critical information or deploying the recorders before catastrophic failure of the platform or loss of all electrics?

By the way, I don't think any such system (deploying recorders) exists but that is beside the point.

We are focussing far too narrowly on a solution that is trying to solve the frustration over the loss of AF447's recorders. What other problems does such a solution resolve? At what expense in terms of money and dedication of resources; with which other flight safety projects or solutions must this concept compete?

It isn't applicable to the majority of aircraft losses where either the recorders survived or were later recovered from a body of water. It has been mentioned a number of times on all AF447-related threads: the number of accidents which remain an enigma and for which we have no clue as to what happened are rare.

Real-time transmission by satellite may become a doable and accepted technology. I have already discussed the security issues which stand in the way of such an approach. They are only partially technical in nature. At some point the will to "do the right thing" will be overtaken by financial considerations and the true reason for the existence of flight data will become moot. Like cockpit video recorders, it can be done but thus far no one has ever come up with a solid process by which such data is not appropriated by the likes of CNN, Fox "News" or You-tube or in the case of flight data, lawyers.

PJ2
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Old 10th Nov 2009, 05:00
  #36 (permalink)  
 
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Let´s not forget that the entire underwater locator beacon only weighs 200 grams or so. The battery lasts for 30 days because that´s the present specification. Adding battery power for another 30 days or even more would be easily done.
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Old 10th Nov 2009, 06:18
  #37 (permalink)  
 
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From reading the papers, it would appear that a lot of days were wasted before they got a submarine on site to listen for the pings.
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Old 10th Nov 2009, 11:00
  #38 (permalink)  
 
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One suggestion already posted here somewhere is to store a copy of all FDR/CVR data in a small, lightweight and fairly "unprotected" memory compartment in the vertical stabilizer.

In recent impacts on water the stabilizer floated and was quickly found in a pretty much intact condition (e.g. AF 447, AA 587, NZ A320)







At different accidents the established fire and crash resistant FDR/CVR would be available.

Last edited by All-Ex; 10th Nov 2009 at 14:32. Reason: thanks sb_sfo
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Old 10th Nov 2009, 13:01
  #39 (permalink)  
 
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All-Ex

Um, that's the VERTICAL stab...
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Old 10th Nov 2009, 13:27
  #40 (permalink)  
 
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All-Ex,
It's still an elaborate solution for an extremely rare problem.

Ad what if the aircraft ditches more or less intact, then sinks to 4000 m with the stab still attached? Back to square one.

CJ
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