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AF 447 Search to resume

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AF 447 Search to resume

Old 8th Dec 2009, 12:08
  #121 (permalink)  
 
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The second (final?) report on AF447 from the BEA is scheduled for 17th December. But in the meantime Air France is
"taking an unusual and high-profile step to assess operational risks, by assembling a group of internationally respected aviation officials to conduct an independent safety review".
What's not to like? More here.
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Old 8th Dec 2009, 14:52
  #122 (permalink)  
 
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Hi,

(final?)
If this is the final report .. be sure the BEA will be listed in the Guiness Book ROFL

I guess a final report will emerge in few years
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Old 9th Dec 2009, 16:40
  #123 (permalink)  
 
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floating FDR?

Would it not be possible to install a second FDR, in a place where it is likely to break loose on impact; and give this second FDR positive buoyancy - foam packing in the case, for instance - and a simple GPS receiver/recorder built in? That way there'd be a record of (a) where it hit the surface and started receiving location information and (b) a track of its movement from when it hits the surface.

Obviously there'd be some drift as the FDR ascended. But as soon as it broke the surface it would start transmitting a beacon that could be picked up by satellites. With a simple trig fix it would then be easy to "go to" - no hunting around, just see where it is and go fetch.

This would narrow the search area considerably - say, to within a couple of nauticle miles drift from release. With positive buoyancy it would come to the surface PDQ - and ascent rate of 1000ft a minute wouldn't be hard to engineer.

With an analysis of ocean current behaviour in the area, it wouldn't be too hard to work out where it had released.

Last edited by rcsa; 9th Dec 2009 at 22:21. Reason: Galileo /Magellan error
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Old 9th Dec 2009, 17:40
  #124 (permalink)  
 
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rcsa,
Like several other people on this thread, you are proposing a very specific, and hideously expensive, "solution", to an extremely rare problem.

A similar accident may not happen again for years and years, and when it happens, it won't be identical.... maybe the aircraft ditches, "digs in", turns upside down, and sinks more or less intact, with your "floating FDR" floating up inside the tail, and still ending up 4000m down......

And why a second FDR? Why, in that case, not modify the existing FDR?

Try to think your suggestion, through, fully. If the original FDR didn't break loose from the wreckage, why should another one do so?

In the case of AF447 there were debris, some big ones, on the surface. Even after trying to plot the currents, there still is no clue to the actual location of the debris field on the bottom.

Some simple suggestions in this thread may make sense.

Pockets of dye marker spread through the aircraft might be a help. Maybe one should go into each life vest?
And contrary to radio-active tracers, they would need no other equipment in the first search aircraft on the spot except the Mk 1 eyeball.

Updating the specs of the "pingers" in the recorders might help as well.
'Crying for help' a couple of days, then go to 'listen and reply' mode, with modern technology in the same unit housing, should be feasible.

We should not try to think of esoteric solutions to an exotic accident, but we should try to learn the lessons.
If some simple action can solve a future accident like this, and at the same time, improve search and rescue, and recovery of the flight recorders, in generally similar occasions, the industry will probably end up implementing it.

CJ
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Old 9th Dec 2009, 19:04
  #125 (permalink)  
 
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Airbus could even use the otherwise not terribly useful Magellan system, therefore going a little way to justifying the billions of €uro spent on Magellan.
One presumes you are referring to the Galileo navigation system?
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Old 9th Dec 2009, 19:48
  #126 (permalink)  
 
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ChristiaanJ
Pockets of dye marker spread through the aircraft might be a help. Maybe one should go into each life vest?
And contrary to radio-active tracers, they would need no other equipment in the first search aircraft on the spot except the Mk 1 eyeball.

Updating the specs of the "pingers" in the recorders might help as well.
'Crying for help' a couple of days, then go to 'listen and reply' mode, with modern technology in the same unit housing, should be feasible.
The dye marker proposal seems simple enough, but by the time you think through what will happen to any liquid bearing the dye after mixing with fresh / sea water in its journey to the surface, the dispersion could be quite significant. The release of this marker dye needs to be in a controlled manner over time, else you finish up with dye on the surface along with any other debris. No different to what we have already witnessed. To implement the dye proposal will be fraught with a whole lot of constraints, e.g. the safety aspects of ensuring it will not be released in other than predetermined situations.

On the other-hand, the cry / listen mode for the pinger is a relatively simple technical solution - software plus exchanging the uni-mode "pinger" for a bi-mode "echo sounder". Battery life in the listen mode would then be extended for many months, as the listen on to off ratio need not be high. A hardware exchange for the existing FDR / CVR is the only implementation required.

mm43
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Old 9th Dec 2009, 20:24
  #127 (permalink)  
 
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My mistake.

Thanks, C-B. Post now deleted.

Last edited by rcsa; 9th Dec 2009 at 22:29.
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Old 9th Dec 2009, 20:33
  #128 (permalink)  
 
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floating FDR

Hi CJ

Good response - thanks. Can I respond to some of your specific points?

I'm not sure this would be "hideously expensive" - very little more than the cost of another FDR (though I have no idea how much an FDR costs), plus the GPS receiver/recorder - 20 bucks worth of technology. Even 'hardened', only a couple of hundred bucks. The GPS guidance units used on JDAMs might be a good place to start.

Sure, un-located, over-ocean accidents are mercifully rare. But when they do happen, a disproportionate effort is spent finding the wreckage; and much of the initial search is focussed on finding the FDR. So it's the old cost/benefit equation kicking in. I suppose the engineering challenge would be to find a way of guaranteeing that the unit broke away, and I am simply not qualified to even think about how that could be done. I guess there are people reading this who might have an idea, though.

I appreciate that debris was found on the surface, at this case and most other over-ocean events - but as we see that doesn't help locate the wreckage. My suggestion would simply give us a better chance of narrowing the search area, as it would begin to track very soon after release. And the point is that by finding the FDR early, at least investigators would have something more than inert debris to work with in the early stage of the investigation.

I like the idea of dye marker in life vests, too - very simple, very cheap.

Ditto the dual-mode pingers. I imagine they'd be easy to to incorporate with the GPS system.

And of course, you are right - KISS rules. Simple and cheap is always more likely to get implemented than complex and pricey. But despite your rigorous analysis, I still feel that what I am suggesting would not be prohibitively expensive, nor techically complex.

I must stress though that although I fly "little planes" for fun, I have no background in aeronautical engineering. But I do fly a lot - often over ocean - on business... so have some kind of vested interest, I suppose!
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Old 9th Dec 2009, 21:57
  #129 (permalink)  
 
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To implement the dye proposal will be fraught with a whole lot of constraints, e.g. the safety aspects of ensuring it will not be released in other than predetermined situations.
Not so. A few solid blocks of dye clamped to heavy parts of the airframe would present no safety issues whatsoever. They could remain in place for the life of the airframe, and only start dissolving at the bottom of the sea.
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Old 9th Dec 2009, 22:11
  #130 (permalink)  
 
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rcsa

My mistake.
Thanks, C-B. Post now edited to correct this.
You not only gave Galileo the wrong name, but a totally inaccurate description.

Perhaps you would care to justify your criticism (in a more appropriate section of this forum) ?
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Old 9th Dec 2009, 22:27
  #131 (permalink)  
 
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Sallyann1234,
It was you who first suggested the dye marker idea, no?

As mm43 mentions, wouldn't most of it diffuse and become virtually undetectable when mostly released from wreckage 4000m down?

I just don't know enough about the properties of dye marker, is there any information about it anywhere on the net?

Oil seeping from a shipwreck can continue rising to the surface above the wreck site in globs for ages, remain visible on the surface, and pollute beaches for ages, too...

So there may be merit in the idea !

CJ
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Old 9th Dec 2009, 22:38
  #132 (permalink)  
 
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@ rcsa.

A second FDR is not as simple as it sounds.
Aside from the cost of a unit, ball park I doubt you'd get much change from $100k - remember that cost is the prime driver for not fitting them to light aircraft, you also have the additional wiring looms to run to wherever the second unit is fitted. This is extra dead weight that the vast majority of aircraft it is fitted to will have to carry around every time it leaves the ground and will never be needed, but which will have to be paid for by it's passengers. Admittedly, not a horrendous sum per ticket, but it's still an extra cost.

Then you have the issue of reconciling data between units - which one is the master, which is a slave & what happens WHEN there is a discrepancy between the data on each unit, what data do you believe.

Associated with this is the separation between the FDR's on the airframe, but fed by a common wiring loom. Even allowing for dual and triple redundancy, it isn't inconceivable that damage to an area of the aircraft could result in some sensor information only going to one recorder & different sensor data streams to the other. possibly the only way to avoid something like this happening would be to have a radio link between the units and record the other FDR's data on each FDR as well as its own, but where do you stop?

Your point about a floating FDR rising at 1000 ft/min is also not so simple. If we assume that in the worst case any debris has to go to the max depth expected on the route (seems to be about 4000m by general consent) then it will be subject to an external pressure not too far from 400 bar/atmospheres or 6000psi (all in very round figures). Most conventional forms of bouyancy simply can't cope with this without being crushed to the point of uselessness. To have bouyancy which is proof against this pressure you need to use fairly specialist material b ut the problem with it is that it is fairly dense.

To get a steady 1000ft/min (roughly 5.1 m/s) on a FDR box about 3 foot x 1 foot x 6 inches you would create a maximum drag force of about 8kN or about 800kg which would have to be balanced by the upthrust due to the density difference between the box and the surrounding sea water. Seawater is more dense than fresh which has a nominal density of 1000kg/cu. m, taking the box sizes above, even if it's totally empty, its volume is only .045 cu.m hence can only displace 45kg of fresh water or maybe up to abot 46 / 47 if you hit a really dense patch of sea.

The problem with the bouyancy materials which can take the pressure is that they are fairly dense, at somewhere between 800 and 950 kg/cu.m (generally solid epoxies loaded with different proportions of glass microbeads) - So unfortunately you wouldn't have a significant upthrust to get a floating FDR back to the surface PDQ without making the container unacceptably huge and heavy.

Sorry to be the bearer of bad news, but I'd say that if anything was to be adopted, a pack of dye under every 10th seat with different time release packaging would probably be favourite. Don't stop thinking though!
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Old 9th Dec 2009, 22:43
  #133 (permalink)  
 
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ChristiaanJ,
I did mention the dye marker previously, but it seems so obvious that I would not claim to be first with the suggestion.
I have seen dye markers used in a marine trial, and the range from which they could be seen was most impressive.
It is true that the dye will disperse rapidly, but it needs only to be present for long enough to be seen by the first search aircraft, which can record the GPS coordinates.
I cannot guarantee it would be 100% reliable, but it would be very simple, cheap, and not require any modification to existing aircraft systems. None of the other suggestions put forward meets these criteria.

Putting dye markers on lifejackets might help with finding survivors, but would be misleading when looking for the sunken airframe and FDR because floating debris is scattered widely by wind and waves.
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Old 9th Dec 2009, 23:01
  #134 (permalink)  
 
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Could the the FDR not have a small radioactice marker source built in?
A dye system with a radioactive dye attached would last longer than a plain dye marker.Simple thoughts,but I am simple.
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Old 9th Dec 2009, 23:38
  #135 (permalink)  
 
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Originally Posted by oopspff7 View Post
Could the the FDR not have a small radioactice marker source built in?
A dye system with a radioactive dye attached would last longer than a plain dye marker.Simple thoughts, but I am simple.
This has been mentioned before....

But any kind of radioactive material still detectable after a major crash such as AF447, with most of the debris and marker 4000m down , would mean a LOT of radioactive material on board every aircraft... which is clearly a nono.

Also, SAR aircraft do NOT carry the highly specialised and sensitive equipment needed to detect trace radioactivity. By the time a specialised aircraft would be 'on site', the tracer would have disappeared.

The first aircraft on site usually carry nothing more sophisticated than a few Mk 1 eyeballs... which lends some weight to the dye marker idea.

Next 'on site' will probably be maritime patrol aircraft that can drop sonoboys to listen for the "pingers", which is why they should remain working for at least a few days.

After that, special sonoboys that could "interrogate" more sophisticated ULBs can be brought in (and by then surface vessels would also be there).

CJ
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Old 10th Dec 2009, 00:44
  #136 (permalink)  
 
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At first sight, dye release seems a good idea, but would the dye stream from great depth rach the surface. Would the dye diffuse far and fast enough to be of any use? If it came from a part, such as a composite fin, that was likely to separate in any breakup and reach the surface, then it could make location of the debris field a bit easier.

I have no knowledge of flight data recorder technology, but I would be surprised if every parameter going into the FDR had its own wire and connection. So providing the same data to a slave recorder would not require a heavy wiring loom, probably no more than a single wire pair, or even a single optical fibre would be needed. A slave CVR, ideally with capacity to record the whole of a flight, could be implemented the same way.

A recent post suggested buoyant FDR that would use GPS to establish where it reached the surface and would broadcast a signal to assist in its being located. The original idea was that triangulation from a number of receivers could give a rough idea of its location. But if it has a GPS receiver, why not add a little more electronics and broadcast its position in the location signal. I believe such a system has been used in recent years for tracking animals in the wild.

The problem of getting a locator to the surface from great depths has also been mentioned, along with the problem of finding materials that would have the necessary strength and buoyancy. It is probably not ncessary to look for something exotic. How about a plastic bag with, at the open end, a block of something that would react with water and produce a large volume of gas. The most difficult thing would probably be ensuring that the gas went into the balloon.

And finally, although AF447 has the highest recent profile, there have been other accidents in recent years where the location, on land or under water, has been difficult or impossible to find. Some of the ideas promoted on this thread might have been useful in those cases.
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Old 10th Dec 2009, 01:28
  #137 (permalink)  
 
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Deploying a marker prior to impact.....

The first thread had extensive analysis of ocean currents at the time of the crash, but we lacked clues to where the impact occurred. I'm wondering whether it would be possible, or even realistic, for a pilot under extreme duress (impact certain) to initiate a fuel dump, to leave a kerosene trail leading to the exact spot?
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Old 10th Dec 2009, 02:54
  #138 (permalink)  
 
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I appreciate that sweeping changes (dual FDRs, et cetera) would prolly be cost prohibitive.

But what about a simple kit for frames dedicated to long-haul overwater flights?

I would think that a very basic "paste on" unit that would sense immersion in salt water and self-detach from the fuse (or wherever) would be enough.

If it were a flatish thing which didn't affect aerodynamics, there wouldn't need to be a whole lot of recert activity.

It could then float, ping, and access the same satellites that ships' beacons use, albeit with a different code.

That would at least give an initial clue as to where to look.


.
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Old 10th Dec 2009, 03:27
  #139 (permalink)  
 
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Why Bother?

What can be found that would matter?

We already know the pitot probes were crap.

We already know AF wasn't using the latest and greatest WX radar.

We already are pretty sure the pilots never received adequate training in using the WX radar.

We already know a lot about the crash.

If something unique happened, it won't matter in the future, and if this crash is the first failure of a trend, the next one will surely happen where the pieces can be found and pieced together.

In the months since this crash, thousands of people have died from wrong drug ingestion and other highly preventable accidents. Let's put our money to work where it'll pay dividends.

Solving mysteries is good sport, but at what cost?

GB
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Old 10th Dec 2009, 09:04
  #140 (permalink)  
 
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GB
In the months since this crash, thousands of people have died from wrong drug ingestion and other highly preventable accidents. Let's put our money to work where it'll pay dividends.

Solving mysteries is good sport, but at what cost?
Couldn't agree more - but in this case, "the already know", is rather speculative!

Better we find out what really did happen.

mm43
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