AF 447 Search to resume

[vanHorck]

NOSJOURNAAL - Nieuwe zoektocht naar Franse Airbus (http://www.nos.nl/nosjournaal/artikelen/2009/11/8/081109_nieuwe_zoektocht_airbus.html)

The search for the FDR and CVR is to resume according to a French junior minister during a commemoration service in Brazil.

He stated the renewed search will commence in February.

[vanHorck]

AFP: Vol AF 447: crmonie sobre Rio en souvenir des 228 victimes (http://www.google.com/hostednews/afp/article/ALeqM5gIWIXxLttDYsPERe3vpM_u09jcdQ)

According to this document the statement is to be attributed to Maarten, a spokesperson for the victims. His statement (at the bottom) is however not a request or hope but seems to be a statement of fact.

[ChristiaanJ]

Tailstrikecharlie,
Acting your age, I see. Your remark is so infantile .....

Apart from that, I suppose there is already a discussion about the likelihood of finding a widely scattered wreckage field at a depth in the order of two to four thousand metres, after months, with any clues like the under-water beacons now silent?
Leave alone finding a couple of small rectangular boxes, similar in size and appearance to a lot of other "stuff" .... AFCS computers, for instance? ... which by now have probably sunk into the bottom silt.

Any link to a halfway sane discussion would be welcome.

CJ

[Me Myself]

Although extremely remote, the possibility of finding the boxes exists. It's been done before ( SAA off Mauritius ). It would an incridible strike of luck and a more than welcome one. I can understand the families want answers but the aviation community too. Whatever the findings, it will be something to act on and will put a stop to these pathetic drivels like the senile one above.
Seeing the commoration on Tv only triggers thoughts of sadness, anger and frustration at not being able to provide answers and corrective actions.
I never gave 2 thoughts about travelling on a 330, but now and time isn't helping, I have to admit that if given the choice, I'd rather fly on a 777. That's one of the reasons I'd really like to see those boxes found.
Tailstrikecharles, french kids often say " celui qui dit, c'est celui qui est " which translate like :
You are only projecting your own sick and wicked thoughts.
Maybe you're in the habit of cooking the books in your professional life ??

[fireflybob]

A day or two after this accident one of the top salvage experts was interviewd on BBC Radio 4's Today programme. He was adamant that the recorders could be recovered. He also said the task would not be easy but said that it had been done before. I suppose it's possible he was touting for the business but it didn't come across that way.

[11Fan]

From my perspective as an employee of an OEM, finding the boxes is incredibly important. National or Manufacturer prestige is secondary to determining the cause. There is so much more at stake.

Also, since it will likely come up, in my two plus decades of experience, there is no personal animosity between the two primary OEM's from honorable employees. While there is pride in our respective products, there is also a mutual respect, as well as sympathy when the other has an event.

I've found that the A vs. B arguments -as a rule- are not instigated from folks who actually work for A or B, rather, they are championed by those who have very little, if any, "skin in the game" and are generally dismissed by those of us who do.

[Finn47]

This article mentions that the 3rd phase of the search was expected to start before year´s end but is now postponed "until at least the end of February":

Air France crash memorial in Rio amid criticism | ajc.com (http://www.ajc.com/news/nation-world/air-france-crash-memorial-189328.html)

That´s four months away. While a delay of a few months may not matter much at this stage, what might be the reason? Bad weather conditions this time of the year? Boats and equipment not available right now? Nobody wants to pay Christmas bonuses to the searchers?

[grizzled]

RE the timing for resuming the search.

I would guess (and it's only that) the main reason for the delay is due to arranging for the most appropriate equipment for the task. The actual search equipment used for the first search, though very good at what it was intended for, was not necessarily the best for that specific task. In the past couple of years (months even) several new submersibles have been developed that would be significantly more effective. The main problem is these vehicles are not just sitting around waiting for someone to call and book them. Once developed and available they very quickly get booked full time for research (usually academic) for years.

I would suggest that it has taken a great deal of negotiation (and money of course) to secure the appropriate equipment, and to do so for the length of time needed to complete a thorough and adequate search.

grizz

[robertbartsch]

Who is paying the cost of the extended (new) search?

Does anyone know how deep manned or unmaned subs can go; I thought it was less than a mile. I know the Titanic was fairly deep.

[djp]

Why do they not make responders for underwater "listen" , rather than sending out pulses when no one is listening . This way the recorders could "live" for months in listen mode . Hear a sonar and then respond with a stronger beacon signal.

[Herod]

Best suggestion I've heard for a long time. Any manufacturers here like to comment?

[PJ2]

A320 operation anomalies . . . Engine Acceleration Deficiency at Low Altitude . . . Baro-Setting Cross Check . . . Investigation irregularities . . .
Another candidate for the auto-ignore button.

grizz, 11fan, a couple of fine contributions to the discussion. I think your posts reflect the opinions of those who know and do this work: Finding the boxes is extremely important.

Edit: Auto-ignore button highly recommended.

[lexxity]

Does anyone know how deep manned or unmaned subs can go; I thought it was less than a mile. I know the Titanic was fairly deep.


Titanic is 2.5 miles down, give or take. Google Woodshole Oceanographic Research facility and Dr. Robert Ballard.

[tuj]

Why do they not make responders for underwater "listen"In order to listen, the beacon would have to expend constant power. By pinging, it doesn't use power between pings. I would agree that a louder but less frequent ping would seem to make a lot of sense.

As for the recorders, its not so much how deep they are as how mountainous the terrain in that part of the ocean is. If it was all perfectly flat and just really deep, I think they would find it pretty easy. With terrain to deal with, debris can shift and keeping ROV's off the bottom becomes much harder. The boxes could be between 2500 and nearly 4000 meters of water in that part of the ocean. The "Jason" ROV can operate down to 6000 meters.

[Me Myself]

Who is paying the cost of the extended (new) search?


Both Air France and Airbus are.

[Hiflyer1757]

Looked at the Woods Hole site and their equipment pretty well booked out for 2010...which jibes with the poster upstream remarks about these type of top notch vessels pretty well tied up and not available on the fly routinely. I would also think that the time frame stated may be a period of better weather in the area also.

I also agree with the 'not a vs b' comment upthread...aviation accidents and their full and complete investigations benefit everyone. Incomplete investigations more often than not only create more questions than answers and thereby an even larger area of uncertainty.

I was surprised by the minimal assistance from other major military powers both right after the incident and later. Yes...it was a Brazil and French show and perhaps that held back some assistance besides the US P3 and the towed array. When the pingers were still active I would think it would have been a great training scenario....and would be even now. The US Navy brought in Cdr Ballard to find the Scorpion and Thresher...and that same Navy owns Alvin from Woods Hole....there is a lot of US parts in that aircraft and it has been under consideration as a replacement tanker for the USAF so there are good reasons for further participation.

[fflyingdog]

Why do we still need CVRs and FDRs as pyhisical boxes onboard the aircraft ? Perhaps we should be looking at a better from 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 ,that downloads to an airlines own server. Its server could constantly scan and monitor the data and possibly be able to spot a developing problem that the crew are not yet aware of and warn them ? The systems storage could be a controlled quarantine area where aircraft data could be stored for an indefinite period to aid accident investagation if needed.

[ChristiaanJ]

Any link to a halfway sane discussion would be welcome.Good to see there IS some sane discussion!
Even if interspersed with nonsense (I thought Habsheim was settled, except among the conspiracy bats).

As to djp's suggestion about a "listener".... I like it!
Contrary to what tuj says, "listening", with modern technology, would consume far less power than regular "pings".
So pinging for a few weeks, then listening for a few months, is a good idea. It would need a new module inside the FDR and CVR (or rather inside the beacon), which doesn't exist yet, so whether there will be enough of an impetus to update the beacons, for what is a rare occurrence, is an open question.

Totally agree with tuj's other remarks. It's almost like the search for Steve Fossett's plane, and over a similar or larger area, and a few miles down under the sea. And no way a hiker will stumble on the wreckage this time....

CJ

PS for tuj
I know it's a lousy analogy.... but look at a kitchen timer.
The very much passive timer display uses extremely little power. The battery usually would die from old age rather than being exhausted... we're talking microwatts.
Your kitchen timer bleeper puts out milliwatts of sound each time. Use it every day, and you have to replace the battery every year.

As I said, not a very good analogy, but a "listener" circuit would still use an order of battery capacity less than a "pinger.

[ChristiaanJ]

Looked at the Woods Hole site and their equipment pretty well booked out for 2010...
With all the other issues of "equipment".
I would think they'd now have to look for a far larger wreckage field in a far less known location...
I would also think far less of AF447 is still in one piece, so the analogy with the Titanic or the Scorpion or Thresher doesn't really hold.
On a 'messy' rocky seabed how are you going to distinguish something the size of an FDR from the rock next to it?
I'm not even sure the tools exist....

CJ

[HamishMcBush]

28 days of pinging is usually sufficient to find the black boxes. Sure you could make the pings last for longer but this would mean a larger battery pack, adding weight too. Where do you draw the line at size, capabilities, amount of data held etc? So far 28 days has proved adequate on all but a handful of occasions. The Airbus that crashed in the Black Sea had its boxes recovered despite one being buried in sediment.
I am lead to believe that it is most likely to be the undersea terrain that has caused issues with finding AF447, with resembalnce to underwater Alps. If the boxes have slid into the equivalent of a ravine, they will never be found.
Look here for the Black Sea incident:
News and Events > Latest News > Press Release : Sonardyne International Ltd. (http://www.sonardyne.com/News/PressReleases/2006/black_box.html)

[vovachan]

Why not have floating black boxes? After all a lot of the lightweight stuff did float up to the surface.

[ChristiaanJ]

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

[fflyingdog]

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 .

[ChristiaanJ]

HamishMcBush, thanks for a lot for your link.
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

[Sqwak7700]

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. :ugh:

[ATC Watcher]

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 (http://www.amscanada.com/company/solutions_products/afirs_uptime/)

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 .

[vovachan]

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

[11Fan]

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

[md80fanatic]

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.

[ChristiaanJ]

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 (http://www.amscanada.com/company/solutions_products/afirs_uptime/)
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

[ChristiaanJ]

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 itGood 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

[Matari]

On pinger life, this website says (http://www.flightglobal.com/blogs/unusual-attitude/2009/06/af447-could-this-be-what-finds.html) that Dukane (http://www.dukcorp.com/seacom/products/beacons.htm), 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 (http://www.flightglobal.com/blogs/unusual-attitude/2009/06/af447-could-this-be-what-finds.html) 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 (http://www.cctechnol.com/uploads/UUVS_AUVExperiences.pdf), discussing how the Ark Royal was found, etc. (note: link downloads a .pdf file).

[PJ2]

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

[goldfish85]

I understand that military transports can deploy floating recorders.

Cheers,


Dick

[PJ2]

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

[Finn47]

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.

[4Greens]

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.

[All-Ex]

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)

http://blog.flightstory.net/wp-content/uploads/af447-tail.jpg

http://poneke.files.wordpress.com/2008/12/airbus-tail.jpg

http://users.rcn.com/dderella/Images/Gallery6news/news10.jpg

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

[sb_sfo]

Um, that's the VERTICAL stab...

[ChristiaanJ]

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

[Xeque]

In several earlier posts reference was made to aircraft constantly broadcasting data and the bandwidth considerations that resulted from that.
I agree. But, what's wrong with doing it the other way round? The aircraft does not have to broadcast what is, essentially, routine data all the time but rather let the aircraft broadcast a trigger signal to say 'I'm in trouble' which in turn triggers a detailed interrogation from the base station. A lot less bandwidth used up there methinks.

[ChristiaanJ]

Xeque,
Read some of the previous posts, in particular PJ2's on the previous page.

By the time the aircraft "knows it's in trouble", it may already be diving vertically, with the satellite aerial blown off the roof by an explosive decompression or such-like.

CJ

[vovachan]

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

To the point, jettisoned buoys containing recorders are in fact used on military naval ac, so the technology exists. While it would be overkill for most medium-short range planes flying over land, for the long-range planes which spend most of their life over oceans there is no reason not to have it.

[clearedtocross]

ChristiaanJ about satellite upload:

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.



Agreed. But it is not necessary to stream the full data. Data may be compressed by a method called "delta modulation" whereby only changes of values are transmitted once their base value is established (as in modern video and audio streams). In level flight, compressed FDR data could be reduced to a manageble data stream. Data uploaded this way may not give a precise picture when data changes rapidly (like an FDR) but might still be helpful to establish the sequence of events.

[HamishMcBush]

Re: auto-jettison of black box: How does the aircraft predict when it's going to crash and let the black box go? Interesting idea.
As to other comments, it took time to mobilise the submarines, ships with ROVs etc and send them to the suspected crash site. We had the RovHomer ready in a day or two and despatched it in collaboration with the BEA by air to Africa where it had to be transported to a vessel with a ROV on it, which had to steam to the site etc etc.
Detection relies on "line of sight" to the black box signal emitter, so if box is in a ravine etc, the sound cannot get out and hence you cannot detect it.

[ChristiaanJ]

clearedtocross,
ANY form of data transmission adds a whole string of imponderables, the data link being lost at the critical moment being only one of them.
Having the FDR and CVR "listen" to the aircraft until the last possible second, then try to protect and retrieve those data, has been the method of choice so far.

"Delta modulation" only needs the 'base value' to be corrupted briefly for the data to become unusable, until the new base has been transmitted (video is a good example... we're seeing it here locally right now, with the introduction of digital TV and dodgy reception....)

To me, if something is going to be done, it should be an upgrade of the ULB, with louder pings, and maybe a transponder function after a certain time. Not sure if it can be done within the same "form, fit and function" envelope?
It may be a "sellable" idea for the FAA, ARINC, etc. because it would improve matters in all cases where a recovery from underwater is required.

As to the data transmission idea, one could say we already have a primitive kind of that in the form of ACARS.... without the ACARS messages from AF447 we wouldn't even be able to make any wild guesses.

Re: auto-jettison of black box: How does the aircraft predict when it's going to crash and let the black box go? Interesting idea.Much what I was saying, really. You want those boxes on board to the last second.

CJ

[mercurydancer]

(I'm anticipating the SLF - what do you know about it comments but hey)

The technology may be available to do wonderful things with data trasmission which may be extremely useful. There is no doubt about that. There are concerns about security/bandwidth accessibility/signal conflict etc and all are valid, but a black box tells you what has happened. It is a totally retrospective instrument.

Bandwidth, etc does not come cheap and in pure cost terms alone may I suggest that the cost of developing an all singing all dancing black box may be offset by investing in technology which may prevent an accident in the first place?

[jcjeant]

Hi,

all singing all dancing black box may be offset by investing in technology which may prevent an accident in the first place?

Yes indeed
BTW the unsinkable Titanic is still waiting to be invented :rolleyes:

[vovachan]

How does the aircraft predict when it's going to crash and let the black box go? Interesting idea.

Like a car airbag - G forces

[ChristiaanJ]

Like a car airbag - G forcesCould you use your imagination for a moment, rather than try to find a solution to one extremely rare accident??

On the one hand... we know nothing really about what brought AF447 down, but the G-forces at 40,000ft plus at the top of a thunderstorm can be enough to start a break-up of an aircraft. Do you want to eject the FDR at that moment, before the rest of the sequence? No, obviously not.

On the other extreme, you ditch relatively cleanly, then the aircraft sinks. What G-force are you going to select as a trigger?

If there was a "simple" solution it would long since have been implemented.

CJ

[PJ2]

vovachan;
Like a car airbag - G forces
How would that have worked in the AF447 accident? (I am assuming for a moment that the BEA Interim Report has it right and that the aircraft, intact, struck the sea in a relatively flat attitude with little forward speed, but fairly high vertical speed. Regardless, the question still applies to such a scenario.)

Regarding deployment based upon 'g' loads and air bag deployment sensing and times, let's take a look at some numbers.

I don't know the design metrics for airbag systems in cars but I think I can offer some reasonable parameters which others with the actual engineering knowledge can modify if my estimates are way off.

I theorize that vehicle airbag deployment design would reasonably contemplate 'g' forces which would spike over time periods of less than one half a second which obtain in collisions of the order of 15fps to possibly 200fps. As an aside, I suspect that for most vehicles, a collision at 200fps would not likely be survivable given the compromising of the passenger compartment but we're talking about an airbag system response time as it may apply to deploying a DFDR and CVR.

Takeoff and approach speeds of most transport category aircraft are in the neighbourhood of 130 to 180kts or between 200 and 300 fps. As another aside, nerve impulse speeds can reach about 160fps so the brain would not likely perceive any unfolding event which occurred at higher speeds.

Speeds below 10,000ft MSL are restricted to 250kts with exceptions to this speed limit on departure; that is about 420fps. That's 250kts IAS, so the TAS could be as high as 300kts, or 500fps. Above 10,000ft or FL100, climb, cruise and descent speeds are in the neighbourhood of 450kts TAS, give or take, which is about 750fps.

At the above-described transport speeds, even on the approach, most aircraft travel their entire fuselage length in slightly less than a second, and at climb, cruise and descent speeds, in about a fifth of a second.

By now you will see where I am going with this... The technical requirements to deploy a DFDR and CVR in the time frames described would require substantial design and manufacturing engineering not to mention certification and regulatory standards which must be tested and enforced. If we think about the "how to", the deploying mechanism must sever both recorders cleanly from their mounts and harnesses and fire them away from a structure which would literally be in the middle of an accident, in the time described, (sensing, arming, firing all in, say, a tenth of a second, so as to clear the failing structures). There is the weight penalty to consider as well - fuel burn increases by about 4% of the added zero fuel weight per flight hour - over the life of the airframe, that is a substantial amount of increased burn for what may be little practical return.

I return to my point made in post #36, which offers the notion that the expense and resources required to do this likely do not meet the risk-reward "thought process" let alone a formal analysis. The number of safety initiatives which must compete for industry and government-limited resources would place this kind of solution well down the list I should think. This isn't to say it isn't doable or isn't worth examining but the realities of doing this must be taken into account.

I'm not saying it isn't worth it. What I'm outlining here are some of the considerations which must be addressed when contemplating such a system. I will have missed some things because I am not an engineer or a mathematician but I do know about airplanes and accidents and flight data analysis solutions and off the top of my head these would be some but not all of the considerations.

The other deployment parameters which would continually assess the "health" of the entire system, (airplane, airplane systems, environment, 'g' loadings) and which could possibly be compared to algorithms built to determine when the aircraft is likely in distress, could form an alternative to the notion of "airbags and 'g' forces". Again, this "solution" must compete for limited resources.

Of course, no two accidents are the same; how do we design a system which is "sure it's time to deploy the recorders", without missing something critical?

Let's examine a practical case: - Investigators could only guess what happened in the last six minutes of SW111 because the fire on board destroyed the main electrical distribution system. The batteries likely continued to supply power however. The blunt reality today is, we dont' even have flight data and voice recorders that continue to work when the aircraft's main electrical system fails. Even getting that fixed, so that the recorders continue to function during serious electrical disruptions providing valuable last-second flight data which may hold the key to the entire accident, is a monumental political task and THAT solution is, and should be, already many positions ahead of "deploying recorders".

PJ2

[Chu Chu]

I'm not convinced a jettisonable recorder is worth the expense and effort. But it seems to me the FBW computer would know when the aircraft was no longer recoverable, or at least when it was no longer in controlled flight. It might activate prematurely on occasion, but data on what caused the original upset would be a lot better than no data at all. It shouldn't be that hard to set up the recorder to also jettison if the computer stopped working altogether.

Or you could just mount the recorder in Monty Python's tomato. :O

[PJ2]

Or you could just mount the recorder in Monty Python's tomato.
(Sigh.)

Why bother.

[Finn47]

Can´t remember the specifics now, but the FAA has new rules on flight data recorders now - and the 787 will have an Enhanced Airborne Flight Recorder which, at least, is supposed to have an independent power supply:

GE - GE Begins Delivery of Flight Recorders for Boeing 787 (http://www.geaviationsystems.com/News/Archive/2008/GE-Begins-/index.asp)

[rottenray]

It would an incridible strike of luck and a more than welcome one.
Perhaps. Finding the recorders would certainly be welcome in many areas, but should they provide "ugly" information, not so much in other quarters.


Who is paying the cost of the extended (new) search?Rumor has it, the NTSB has kicked in a few bucks as well. Many US airlines have a vested interest in this, as it will help them assure that many of the AB-I planes in their fleets are, in fact, safe.


The prototype Concordes (well at least G-AXDN) had a jettesonable flight recorder. Why hasn't that idea been developed? There are several problems with the recorder leaving the frame - not the least of which is finding it after it has. Some military airframes have a "deploy" switch for recorder and "pinger" packs, but these are used mostly in the hopes of retrieving crew, not flight data. And, they're not 100% reliable, as even a crew-triggered device can land far away from the actual site.


It's still an elaborate solution for an extremely rare problem.Most assuredly - most flights don't crash. The sticky wicket is determining why those which do did so.


Here's a thought - the pilot community considers downloading of FDR data to be some sort of invasion of their right to privacy while carrying forth the duties which they have agreed to discharge, and unions argue that the information could be used to "rate" pilots at their "desks."

However, a running "concordia" of a plane's performance and how it has been flown might be very helpful in the event recorders cannot be recovered, or recovered in a timely fashion.

Do we know for sure that pitot changes have fixed the problem?

Sort of, but not really.

Were any specific problems with the airframe responsible?

Don't know.

Seems to me that one could "sequester" FDR data for an indefinite period of time, unless the data was needed for the investigation regarding an incident or an accident.

But having the last few flights' worth of data could prove valuable.

At this point, who's to say that particular tail number didn't experience an odd combination of rougher-than-normal landings, well-meaning but less than mfg maintenance on a few items, and rougher than normal handling of cargo hatches, et cetera?

We've been looking for a way for all the "holes" to line up, but, perhaps, we haven't been looking far enough back into the frame's history - and there is nothing to clue us in.

A bump here, a scratch there, throw it all into a magnificent storm, and see what happens...

[ATC Watcher]

Retrieving FDR/CVRs in deep waters has always been difficult. If the orography of the sea bed is what has been reported ( the " Alps" with 4000m deep crevasses) , then the task will be even more difficult. Pingers or no pinger.

Incidentally I was reading yesterday the (excellent) interviews of both the pilot of the Cessna 210 that ditched with 6 POB off the coast of Corsica on 12 October last , and that of the Puma helicopter Pilot who finally found them .
(the C210 pilot was an AF 777 Co and his partner a Flight attendant with some experience ) The C210 was on radio contact until 1min prior ditching, , called Mayday, was under radar contact on SSR transponder, and had a new 406 Mhz ELT coupled with GPS. Rescue SAR knew exactly where the a/c went down. A first helicopter went above that point only 15 min later but failed to spot the survivors.,despite all on orange life vests , but drifting. This was 1400 Loc , full daylight. 3 rescue helicopters and a Breguet Atlantic joined the rescue. They never spotted them , finally when night fell 5 hours later, the C210 pilot activated the small light on his life jacket and that was picked up by an infra red camera of the military helicopter , who got them all 6 out.
Hypothermia, small bruises but all OK.
So even with all the new gear , ELT and all, at sea, it seems extremely difficult to retrieve something floating ,even knowing the exact GPS position 15 min before. let alone FDRs/CVRS at 4000m deep in an area 30 x30 NM months afterward...

[vovachan]

Some additional comments - an airbag reacts in abt 1/25th of a second to a crash. Now let's assume the airliner slams into the sea at full cruise speed of 800 km\h which is waaay too fast. In 1/25th of a second it will have moved 8m or 24 ft if my calculations are correct. Most planes out there are considerably longer than that giving an ejectable black box in the tail plenty of time to eject to safety.

PS If you look at the condition AF447 debris was found in, some of the cabinets floating out there were almost intact, and they look no sturdier than IKEA furniture, so my guess is the terminal speed at impact wasn't that great.

[megla]

Another option - after one month still send the signal, but only once a minute or even hour, so bateries would last MUCH longer. And also - set pulse frequency depending on presure/depth, seems not too hard technically, seems that for underwater search knowing exact depth can be very important clue.Or it is already considered and already working this way?

[HamishMcBush]

Yes, you could add a depth sensor for not much money in overall cost of a commercial passenger aircraft (maybe USD10,000) BUT, and this is the big BUT.... you still need a direct "line of sight" to the FDR to be able to pick the signal up. If it's stuck in an undersea crevass etc, you will never detect it (see earlier posts).

Regarding recent new point raised: I used to work for a company that made automotive crash sensors. Typically these trigger at 14 to 16g. They had to withstand 8g without triggering; every one we made was tested for performance.

Edit: Thinking about it, the RovHomer calculates distance and angle IIRC, so it automatically calculates the FDR depth (or the control software does)

[kaikohe76]

djp,
Very sensible & as so often happens a very simple idea, well done. Now let's see who can be the first to come up with just such a device.
Hope the search does re commence & continue for as long as it takes, yes it's a long shot, but surely worth the effort.

[ChristiaanJ]

Yes, you could add a depth sensor for not much money in overall cost of a commercial passenger aircraft (maybe USD10,000) BUT, and this is the big BUT.... you still need a direct "line of sight" to the FDR to be able to pick the signal up. If it's stuck in an undersea crevass etc, you will never detect it (see earlier posts).I see I need to read up on underwater sound, since yuo mention "line of sight".... Are any of the parameters for the medium, wavelength, transmission, diffraction, etc. at all comparable with light or radio waves in air?
Thinking about it, the RovHomer calculates distance and angle IIRC, so it automatically calculates the FDR depth (or the control software does)Wouldn't the distance measurement be only very approximate? It's not a transponder system, so the only clue is the "ping" strength.

CJ

[netstruggler]

Are any of the parameters for the medium, wavelength, transmission, diffraction, etc. at all comparable with light or radio waves in air?No, not at all.

If you're after a crude analogy then sound propagation through air is better one.

[R04stb33f]

Do passive locator systems such as RECCO (for finding skiers caught in avalanches) function underwater? If such a system could be developped, and assuming the cost / size was reasonable, such "tags" could be incorporated into many of the aircraft parts. This would no-doubt increase the chances of locating an aircraft / debris field in circumstances such as this.

[ionagh]

The maritime equivalent would be the combined EPIRB+voyage data recorder. The engineering would need to be substantially different as the worst they will need to survive is something like a 35m drop test into water.

In terms of energy budgets, any device that is not related to distress alerting ie the FDR/CVR would be better as a transponder only. There is no point in transmitting 'blind', wait until you know someone is actively looking before using any energy reserve.

RF transponder tags like RECCO are 'powered' by the received RF energy and are only effective over very short distances (metres) at the frequencies used, this would be cm in water.

[HamishMcBush]

Wouldn't the distance measurement be only very approximate? It's not a transponder system, so the only clue is the "ping" strength.

The listening device has at least 2 detectors positioned very close together, but far enough apart that there is a time difference in receiving the reply signal. Using very clever signal processing, the distance and angle can be calculated, to within a few centimetres over a couple of kilometres.
IIRC sound travels about 3 times as fast in water as in air. I don't know all the theory and it would no doubt occupy a large amount of space to explain it all here.

[cessnapuppy]

the speed of sound in water (and in air too, to a lesser degree) is intensely variable with factors such as salinity,depth, adjacent layers and such.

it is possible that you could be a few hundred feet away and miss sounds channeled away below. Some advantage could certainly be gained by varying the frequency (pitch) of the ping depending on depth,etc but would be very expensive with very little attributable value.

Best scenario I think would simply be saturating the earth and oceans along the flight path with relay stations (think cell towers) which could capture regular broadcasts (not satellite) of ACARS like information.

The cost of maintaining this network would be offset by having them serve some dual purpose (i.e. we already have ultra sound weather buoys to capture water temperature, weather data etc.)

[Dairyground]

In general, an aircraft carries a single FDR, built and armoured to withstand very high deceleartions and intense fires. It is also located within the airframe in a position where it is likely to remain in the main debris field following any impact.

With modern technology would it not be possible to install several light-weight FDRs, not so heavily armoured or fire-resistant, in structural elements such as the fin or wingtips that are likely to break off in a catastrophic impact, and end up in the outer fringes of the debris field, or even float in the case of a break-up on impact with water.

It should be possible to construct such a recorder with a form factor similar to a mobile phone and with similar power requirements. It could even be fitted with an RFID tag to aid in location.

I'm not suggesting that these mini-FDRs (and CVRs) should replace the current concept, but a lightweight recorder at the top of the fin could have told us much more than we might ever know now about the final minutes of AF447.

[minstermineman]

Be a lot simpler if the aircraft itself routinely transmitted a signal with location co-ordinates, that would generate an alarm if signals were not recieved at 'home'

Last signal = last known location = where to start looking.

You would also be able to work out speed and heading from the previous transmissions so you could search in the right area.

This might provide a better guide to finding the recorders than following floating wreckage and best guesses.

[ChristiaanJ]

Retrieving FDR/CVRs in deep waters has always been difficult. If the orography of the sea bed is what has been reported ( the " Alps" with 4000m deep crevasses) , then the task will be even more difficult. Pingers or no pinger.

Incidentally I was reading yesterday the (excellent) interviews of both the pilot of the Cessna 210 that ditched with 6 POB off the coast of Corsica on 12 October last , and that of the Puma helicopter Pilot who finally found them .
(the C210 pilot was an AF 777 Co and his partner a Flight attendant with some experience ) The C210 was on radio contact until 1min prior ditching, , called Mayday, was under radar contact on SSR transponder, and had a new 406 Mhz ELT coupled with GPS. Rescue SAR knew exactly where the a/c went down. A first helicopter went above that point only 15 min later but failed to spot the survivors.,despite all on orange life vests , but drifting. This was 1400 Loc , full daylight. 3 rescue helicopters and a Breguet Atlantic joined the rescue. They never spotted them , finally when night fell 5 hours later, the C210 pilot activated the small light on his life jacket and that was picked up by an infra red camera of the military helicopter , who got them all 6 out.
Hypothermia, small bruises but all OK.
So even with all the new gear , ELT and all, at sea, it seems extremely difficult to retrieve something floating ,even knowing the exact GPS position 15 min before. let alone FDRs/CVRS at 4000m deep in an area 30 x30 NM months afterward...

Some recent posters, please read this.... and think about it.

CJ

[jcjeant]

Hi,

The maritime equivalent would be the combined EPIRB+voyage data recorder

From far far readings months ago (at the beginning of the AF447 drama) it was noticed this plane was equipped with some kind of EPIRB but they do not function AKAIK by what was posted in this forum times ago.
Methink it's a legal requirement for have this kind of EPIRB aboard airliners.

[ionagh]

The maritime example of EPIRB+VDR was just for comparison. In terms of SAR the required device would be best equipped with a radar transponder (SART). As CJ pointed out, having the exact GPS distress location at sea will give you an exact idea of which SAR unit to scramble but not necessarily exactly where to look. Without either continuously updated GPS coordinate transmission or a SART the search is less likely to give a positive result.

In the maritime field such equipment exists but there would need to be extensive engineering research to ensure survivability and operation in such a case as we have here.

[kiliwizz]

What about alternative detection methods; if a number of strong magnets were dispersed around the airframe (but away from the cockpit to avoid interference with instrumentation), then it is possible that MAD detectors might pick them up (with no power source required).

[Unusual Attitude]

Just wanted to clear up some points in this thread however am very limited what I can say for now.

There is no problem with the avaliablity of the equipment to undertake this workscope. There are a number of suitable vessels currently idle with 4000m rated WROV's spreads on board and ready to go. There are only a handful of suitable deep tow side scan sonar systems around but such a system is indeed avaliable right now. Basically there are no 'equipment issues' causing these delays, I could have a vessel fully mobbed and ready to go in 10-14 days.

The technology above stands a very good chance of finding the boxes, I have seen the resolutioin that this sonar system produces and trust me it can find very small items down to 6000m. Temperature layers are also not a problem, the sonar fish is flown 100m or so above the surface of the seabed and covers a very wide swath, the main problem being the terrain it will need to be flown over.

[atakacs]

@UA
Juste wondering if you could comment about the order of magnitude of the cost involved in operating such vessel ? Also what would be the typical mission for this type of equipment ? Telecom cables ? (very) deep offshore rigs ? scientific ?

[ChristiaanJ]

@UA
I don't know either, whether you can comment on some of the issues?

Do we even know where the debris field is?

What's the resolution of the sonar? How easy or difficult is it to distinguish a piece of 'man-made' debris from the rock next to it?

It's unlikely the FDR and CVR were thrown clear from the rest of the wreckage... more likely they're still stuck in some of the aircraft structure. So much the same question... you're not looking for rectangular boxes, but for the most likely parts of the wreckage. Can the kind of sonar you mention find those?

You obviously would not send a ROV down until you had at least some kind of target, no?

CJ

[rottenray]

Do passive locator systems such as RECCO (for finding skiers caught in avalanches) function underwater?

No, and they sometimes don't function under several feet of snow, depending on the attitude of the slope, wetness of the snow, so forth.

Any beacon signal is a last-ditch effort - broken beacon, unfavorable conditions.

Seriously -

Having a transponder detach from a frame is only good in a military situation where you can assume several other craft will be in the same general area and can actively locate the transponder.

Trying to transmit all the parameters recorded by the recorder(s) is a nice idea, but unrealistic at this point mainly due to cost. Unrealistic also considering bandwidth - not that a "perfect" connection would not be able to transmit all the data, but assume that an imperfect connection would not be able to transmit enough of it faithfully.

What could be done is this - very short bursts of data which include indicated position and perhaps GPS position, transmitted every 2 - 5 minutes.

Just having that data would reduce the search area tremendously. If you used 2 minutes as the design "center" value, then you'd be able to tell within a few dozen miles exactly where a flight stopped relaying data, and from that you could narrow the search area greatly, perhaps to less than 100 miles.

The "guess" zone for 447 was huge initially, and was eventually refined to another "guess" based on ocean currents, but the true location hasn't been pinpointed yet.

If one could have started the search assuming 100 mile accuracy, the boxes might be in the lab by now.

Point being, it's not so much what you transmit, it's where and when you transmit.

ACARS hasn't been too much help. The pingers on the outside of the boxes haven't been too much help.

What would have really helped would have been a simple lat+long from the aircraft, updated for as long as possible, even transmitted through ACARS.

[Fargoo]

From far far readings months ago (at the beginning of the AF447 drama) it was noticed this plane was equipped with some kind of EPIRB but they do not function AKAIK by what was posted in this forum times ago.
Methink it's a legal requirement for have this kind of EPIRB aboard airliners.

406Mhz ELT's are usually installed on any large transport these days. No idea if thats what the AF had fitted but certainly what BA uses.
The have a foam float around the unit but for it to be effective it first needs to break free from the fuselage and reach the surface.

[Ex Cargo Clown]

How about a frangible, or even soluble part of the fuselage that releases a photoluminescent dye ?? Even if currents move it would give you a very good idea, and very quickly where the wreckage was.

Would also cost a pittance.

[Storminnorm]

Or even yellow plastic ducks?

[Ex Cargo Clown]

Or even yellow plastic ducks?

You can see my dye by satellite :)

[Sallyann1234]

Simplest ideas are usually the quickest to deploy, and often the most reliable.

Place one or more blocks of bog-standard marker dye under seats or behind panels.

The passenger compartment invariably breaks up on striking the sea surface or is crushed by depth pressure, thus exposing the dye to water and starting a trail in the sea current.

Any airline could do this right away as a voluntary measure. Very little design required, no airframe changes, no type approval or certification.

The extra weight? Probably no more than a couple of bottles of booze.

[ChristiaanJ]

Sallyann1234,
Do you know any technical details about the stuff (I don't, which is why I ask)?
How much would you need for a really big stain that persists for a couple of days in a heavy swell?
And wouldn't it be affected by wind and current in the same way as debris?

And talking debris, how often does an aircraft end up in the water without leaving at least some debris on the surface anyway?
In the case of AF447 there was an entire tailplane... it still did not help in finding the sunken wreckage, leave alone the FDR and CVR.

CJ

[vovachan]

I hope the Brazilians have finally gotten around to doing the forensics on the bodies. This would give some idea of the speed at impact, and what happened to the fuselage, and what to look for. My guess is the speed wasn't that fast and the plane broke into several large chunks.

[HamishMcBush]

To give you all an idea of what is being sought, this is how small the FDR is.....

This one is still attached to the ROV that recovered it.http://i23.photobucket.com/albums/b352/IvorETower/Aircraft_black_box_c.jpg

[ChristiaanJ]

HamishMcBush,
Even shorther than some I've seen and handled......
Do we know the type of the FDR on AF447?

[vovachan]

This is assuming the FDR broke free of the fuselage which it probably didn't. That's why they couldn't hear the pinger - it is enclosed in a piece of the plane which is lying on the seabed, like the Titanic.

[Unusual Attitude]

In response to the following:-

-@UA
-Juste wondering if you could comment about the order of magnitude of the -cost involved in operating such vessel ? Also what would be the typical -mission for this type of equipment ? Telecom cables ? (very) deep offshore -rigs ? scientific ?

Not willing to go into costs at this stage other than to say that the whole spread (vessel, WROV, deep tow sonar & personnel is considerably sub £100k per day.)

Typical workscope for such a sonar spread is pretty much as you state above, scientific, deep wreck search, deep telecoms cables, pipeline route survey, not rig related however at those depths.


-@UA
-I don't know either, whether you can comment on some of the issues?

-Do we even know where the debris field is?

-What's the resolution of the sonar? How easy or difficult is it to distinguish -a piece of 'man-made' debris from the rock next to it?

-It's unlikely the FDR and CVR were thrown clear from the rest of the -wreckage... more likely they're still stuck in some of the aircraft structure. -So much the same question... you're not looking for rectangular boxes, but -for the most likely parts of the wreckage. Can the kind of sonar you mention -find those?

-You obviously would not send a ROV down until you had at least some kind -of target, no?

A working group is currently in place to identify the search area.

Typically, given the length of cable behind the tow vessel (upto circa 10,000m) a series of runs will be made within a box, once the box is complete any targets identified by the sonar passes will then be investigated by the WROV.
It is not a case of differentiating between simply 'black boxes' and rocks, any wreck be it aircraft or ship will leave a debris field, usually over quite a large area. Such an area would be rather obvious and would warrant further investigation with the WROV using both video and hi-res multibeam sonar to map the debris field. Such a hi-res multibeam system can pick out items as small as a coke can.

[Sallyann1234]

@christiaanJ
I have seen marker dye deployed from a liferaft during a maritime exercise. The distance that it could be seen from the air was amazing - long before the raft itself was seen. The size and profile of the raft was not too dissimilar to the floating debris from an aircraft.

I'm suggesting that the dye capsule would be secured within the airframe, so that the marker train originates from the seabed location rather than from the floating debris.

[HamishMcBush]

I was fortunate to be involved in a conversation with a senior manager at the company where I work today. I am told that the company I work for is putting pressure on the airline industry to update the 30+ year old technology used by the pinger system and to aim to have FDR's use a transponder system, so they will not transmit until interrogated. This will mean that the battery life will increase, to up to 5 years.
We can do with support from those in the aviation industry to take this further, I am sure.

[ChristiaanJ]

Sally Ann,

Thanks, sounds like another halfway sensible idea worth exploring?

As you said, the equivalent of a few bottles of booze spread through the aircraft might do the job.

Still, I'm less convinced that a "marker trail" from a wreck 4000m down wouldn't totally diffuse before it got to the surface, or wouldn't be so far displaced by currents, that it would not be any rel help.

CJ

[HarryMann]

Still, I'm less convinced that a "marker trail" from a wreck 4000m down wouldn't totally diffuse before it got to the surface, or wouldn't be so far displaced by currents, that it would not be any real help.

But better than no help, surely...

It is simple and probably effective and better than not having that capability, no?

[c7xlg]

RE: Tracer Dyes. These are often designed so that even if the dye isn't visibile to the naked eye by exposing a sample of water to UV light the dye glows in a way that can be detected electronically.

In this way the dye can still be detected when it is diluted down to levels way below is being visible to the naked eye. In fact in some situations where they are used this is the preferred method. For example releasing the dye into a stream at the start of a cave network and sampling the rivers coming out of the caves to see if they are connected. The locals tend to get funny if you turn the whole rivers purple, hence using dyes at levels to be invisible to the naked eye, but still detectable is standard practise.

So in the AF scenario by taking samples of surface water and testing for presence of the dye over a very wide area you could find traces and focus the search in to the areas with the highest concentrations.

[lomapaseo]

So in the AF scenario by taking samples of surface water and testing for presence of the dye over a very wide area you could find traces and focus the search in to the areas with the highest concentrations.

How long would this take in this search?

[Sallyann1234]

How long would this take in this search?

Agreed. Chemical analysis would not be practical.

I envisage a slick of dye emerging on the surface downstream of the wreckage on the seabed, which in clear weather would be visible to a wide-area search more quickly than pieces of floating debris. It only needs to be there long enough for the first search plane on the scene to record the GPS coordinates of the start and end of the slick, allowing a pretty good extrapolation to the seabed location.

I don't pretend for a moment that this would be foolproof, but it could be a valuable extra pointer to the location of the FDR.

[RatherBeFlying]

How about a really long tether fastened to the fin and fuselage:}

[good spark]

just how long do you propose this lanyard to be?






gs

[FlyBoy737800]

Guys IT WILL NEVER BE FOUND !

It's in Airbus and Air France best interest for it NOT to be found.

Look at the BIG picture Luke :sad:

[ChristiaanJ]

Oh come on Flyboy...

If you'd been following the story properly, you'd be already aware of the precursor events, and the amount of neglicence being demonstrated thereby....

Getting hold of the FDR and CVR would at least narrow down the story.
It might even allow the "perpetrators" to blame it all on the crew.

So put some more peanut butter on your tinfoil hat, and let it be.

CJ

[Finn47]

Anyone have an idea about in how many cases, say in the last 30 years, the boxes have not been recovered or the data had been destroyed beyond being of any use?

[Razoray]

Incident: US Airways A333 over Atlantic on Nov 17th 2009, computer issues

By Simon Hradecky, created Friday, Nov 20th 2009 14:30Z, last updated Friday, Nov 20th 2009 14:30ZA US Airways Airbus A330-300, flight US-740 from Philadelphia,PA (USA) to Madrid,SP (Spain), was enroute at FL390 about 350nm east of Philadelphia overhead the Atlantic about 40 minutes into the flight, when the crew announced they needed to return and was cleared to turn to the left. About 40 seconds later during the turn the crew declared emergency and requested to descend. About another 5 minutes later while levelling at FL300 the crew reported, that everything had returned to normal explaining, that they had experienced computer problems they were unable to resolve and they had been "missing control". The emergency was cancelled, the airplane continued back to Philadelphia. The airplane landed safely on Philadelphia's runway 09R about 75 minutes after the onset of trouble.

[steamchicken]

Probably the biggest use-case for those ships is as cable ships; there's always a mad dash to charter them when there's a bad cable break. A few years ago, when there was an earthquake at sea in the straits between Taiwan and Okinawa which took out multiple cable systems, there were something like 6 vessels on station at once, and a lot of people hoping nothing else broke for a while.

The two biggest operators are Alcatel and Global Marine Services of London. Which should make the usual suspects wet themselves all over again. didja no it a FRENSH airplane with LIMEY wings?

[GearDown&Locked]

Simplest ideas are usually the quickest to deploy, and often the most reliable.


Just make the fuel traceable. Wouldn't be too hard/expensive to do it.
Even in the event of an inflight breakup it would narrow down the search area quite considerably.

It's been already done when adding specific smell to gas for safety reasons.

[Sallyann1234]

NOT a simple idea.

Even in the event of an inflight breakup it would narrow down the search area quite considerably.
Fuel discharged at altitude scatters over a large area and largely evaporates.

Just make the fuel traceable. Wouldn't be too hard/expensive to do it.
In the case of AF447 there was little trace of fuel. How would a marker within it have helped?

What sort of fuel additive could be produced in sufficient quantities to trace all fuel used in all trans-ocean flights, in sufficient concentration to show up immediately in a search, but without acting as a contaminant at any combination of environmental extremes?

No. A marker needs to be non-consumable, and close to the structure that is to be located.

[Finn47]

.. it seems wikipedia already has a list of unrecovered flight recorders, though how complete it is is anybody´s guess:

List of unrecovered flight recorders - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/List_of_unrecovered_flight_recorders)

The boxes have been proven crash proof, fire proof and water proof. Making them easier to find in deep waters should be an immediate priority. Of course, retrofitting all airliners with improved pingers, for instance is not an easily accomplished task but what else is there?

[GearDown&Locked]

No. A marker needs to be non-consumable, and close to the structure that is to be located.
Point taken.

Some underwater cameras use a calibrated compressible marker in the event of going under the max certified operating depth for warranty reasons. A simple dye marker bottle with a similar device (frangible in this case) on it's cap, attached to the boxes themselves should do the trick.

If we wanted to spend some good money, it could be possible to use some of the old missile technology, and fire/unlatch a very small and conspicuous boey attached to a thin and long wire from a small box on the exterior part of the plane. It could be used as the beacon antenna . Conditions to deploy it: depth and lack of movement.


There is already a similar system used for submarines today. Example here (http://www.janes.com/articles/Janes-Military-Communications/SEPIRB-T-1630-SRT-expendable-submarine-launched-emergency-beacon-United-States.html).

[steamchicken]

Come to think of it, if you need a marker that's detectable at low concentrations and remotely (for example, from a maritime patrol aircraft), isn't the answer a radioactive substance? It's been done for various purposes.

No point putting it in the fuel for reasons given above. But some kind of structure designed to breach easily could do it. Of course, using teh radiations would run into all kinds of other problems (just think what the chemtrail types would say - or is that a feature, not a bug?)

[Brian Abraham]

Posted here as the other threads re 447 seem to be locked. Mods please do as you see fit, just thought it an interesting incident, given possible similarities.

From November issue of Aviation International News.

http://www.ainonline.com/news/single-news-page/article/pilot-suspects-static-electricity-in-citation-x-pitot-failures (http://www.ainonline.com/news/single-news-page/article/pilot-suspects-static-electricity-in-citation-x-pitot-failures/)

Pilot suspects static electricity in Citation X pitot failures

By: Vladimir Karnozov
November 1, 2009

Static electricity may cause pitot static probes to fail, according to a Cessna Citation X owner-pilot who survived a simultaneous failure of all three pitots during a flight earlier this year. Kirill Minovalov, a Russian entrepreneur and private pilot, was flying in stormy weather conditions when the incident happened; he managed to land safely at Moscow’s Domodedovo Airport.

Minovalov, 38, was quick to take advantage of Russia’s economic reforms in the early 1990s. In 1994 he formed Bank Avangard and still serves as its president and CEO. He was urged by the Russian Business Aviation Association to discuss the serious safety incident and spoke exclusively to AIN.

Seven years ago, Minovalov bought his first aircraft, a Dassault Falcon 10, and he has since logged 2,500 hours as a pilot in that airplane and the Citation X. He also owns an AgustaWestland A109 Grand, in which he has 350 hours.

On July 27, Minovalov was at the controls of the German-registered Citation X. Built in 2003, the airframe had logged nearly 2,400 hours and 1,660 landings.

Due to thunderstorms in the Moscow area, air traffic controllers placed the airplane at a rather high altitude, 39,700 feet, over the villages of Sukhotino and Skurygino (22 miles south of central Moscow). At around 1 a.m. the crew was cleared for descent.

The initial descent was rapid, at 5,500 feet per minute, and in between two thundercloud fronts, 25 nm to the right and 40 nm to the left. At around 34,500 feet the Citation X entered heavy turbulence.

A minute later Minovalov and his German copilot saw light shining on the other side of the windshield. “For the first time in my flight experience I saw an electric charge; it was shining brightly like welding [torches]. A golf ball in size, it was sitting on the shroud of the windshield airflow system,” Minovalov recalled. Apparently, a huge amount of static electricity had amassed on the airframe. Its protruding parts, such as the shroud and, quite possibly, pitot probes, were carrying high charges of electrical current, Minovalov surmised.

Thirty seconds later the pitot heater fail left warning light came on. The crew was not too concerned about this since the speed indication remained accurate. But after another 30 seconds the speed-measurement system suffered a complete failure. All three pitot static probes were apparently producing incorrect readings.

The captain’s and copilot’s indicators gave an airspeed reading of some 40 knots, while the standby instrument was on zero. Pitot heater fail right and pitot heater fail sb warning lights came on. The pilots also got an audio low-speed warning at this point.

The incorrect speed reading caused the yaw damper to disengage and issue the warning yd fail–lower. Other aircraft systems responded to the false readings. For example, mechanical limitations for rudder and aileron deflection adjusted to the wrong speed reading.

The Rolls-Royce AE3007C1 engines produced enough thrust, but their full authority digital engine controls (Fadec) reacted to the erroneous speed reading by activating reverse [reversion] mode and generating a fadec rev adc l-r message.

The cabin pressurization system appeared to be fooled by the wrong speed reading. Both pilots sensed bad pressure settings with their ears; it was rather uncomfortable, but bearable. Later Minovalov discovered that control of cabin pressure and pitot heat in the Citation X is linked.

“Having accepted the controls, I felt the yoke and pedals had wrong gearing for the actual speed, requesting very careful handling,” explained Minovalov. A sharp deflection of hydraulically boosted control surfaces might have led to entering dangerous flight regimes or airframe structural damage.

To their credit, the captain and copilot acted in unison, sharing a common view about how to cope with the situation. The crew preferred “vertical speed” mode to “flight level change” in following the flight directors and ATC commands. They focused on keeping airspeed within the safety corridor while descending at some 2,500 feet per minute, once heading, gyroscopic horizon, barometric altitude and descent rate readings seemed correct, and the radio and flight directors remained intact.

“We flew through darkness sparked by lightning flashes all around, no visual reference to the ground,” Minovalov recalled. “There was a strong feeling the airplane had been flying too slowly, and it was tempting to add thrust. But doing so may have resulted in [exceeding] Vne [never exceed speed].”

The crew asked air traffic controllers to keep them informed of their groundspeed. “I did not know what the wind was, but, having information on speed from the ground, I could figure out that, despite the feeling of too low a speed, the airplane in fact flew rather [more] fast than slow.” When the airplane was at 27,900 feet, the air traffic controller reported ground- speed of 397 knots.

The shining ball of light outside remained visible for a minute or two. “I cannot recall exactly when it vanished since I was preoccupied with smooth handling and keeping safe speed, while the siren screamed alarm. But the ball was certainly on for quite a while,” Minovalov said.

The Citation flew in turbulence for some four minutes, getting out of it at about 19,500 feet. Back in stable air, the crew checked the circuit breakers. Then Minovalov tested the system by pressing the yaw damper button. Everything went back to normal and the yd fail-lower light went off. In a split second the system displayed the correct speed reading.

Then Minovalov turned on the autopilot, which also worked. Some warning messages remained on the screens for another couple of minutes and others disappeared one by one. Pitot heater fail lights went off midair, and fadec rev adc l-r at landing. As the airplane taxied to its parking position, no warning lights were illuminated.

The next day essential information about the case–including files from flight recorders–was passed to FlightSafety International and Cessna.

Not an Icing Incident

At the request of the manufacturer, the pilots discussed the incident with Cessna over the phone. It was hard for them to convince Cessna that the incident had not involved icing. “I frequently fly from Moscow, sometimes to Innsbruck [in Austria], and so I know very well what icing is like,” insisted Minovalov.

In his view, the symptoms were different from what would have happened if the pitots had been iced up. The speed readings on all three indicators dropped simultaneously, while icing normally causes smooth changes depending on the altitude. All three pitots failed within a split second and started operating again in tandem. What’s more, there was no rain and the ambient temperature outside the aircraft was -15 degree C.

Minovalov is convinced that static electricity was the root cause of the pitot failure. He believes that a static electricity charge can create a plasma that affects the air flow. Rather than being stuck, the pitot static probes were not getting a rush of air flow, which resulted in all of them having the same incorrect speed reading from the pressure measured on both ends of the tube. Incoming airflow was unable to create a difference in pressure since the plasma prevented it from entering the pitot probe.

Minovalov and his crew were back flying in the Citation X the next day. He said that he had complete faith in the aircraft.

“What happened the previous night was merely a natural phenomenon,” he said. “Static electricity charge and plasma build up in certain weather conditions and naturally disappear when ambient conditions change, leaving aircraft systems intact. In a way, it is like icing: the substance builds up and disappears, and the airplane is fully operable again.”

Soon after the incident the Citation X underwent scheduled maintenance, and all systems were found to be working. Neither the manufacturer nor aviation authorities required any additional work on the airplane.

“After that flight, I began my own research into what happened, this natural phenomenon. I also read much about Air France Flight 447 [the June 1 crash of an A330-200 into the Atlantic Ocean],” he told AIN. “In my view, we experienced the same phenomenon. We both flew in heavy turbulence. The French crew also radioed about static electricity charge. It could be nothing else but them actually seeing a shining ball. There is some evidence that the A330-200’s engines changed mode; in my case the Rolls-Royces went into reversion. Reportedly, the other airplane had also had the yaw damper and autopilot disengaged. It seems to me that the chain of events and the flow of failures were much the same in their case and mine.”

However, there are differences between the two incidents. Unlike the Airbus over the middle of the Atlantic Ocean, the Citation flew over land in the vicinity of airports, with sufficient ATC support. “Seemingly, in my case it was a lot more comfortable, morally and psychologically,” Minovalov admitted. “Besides, it was easier to maintain safe speed on descent than in level flight at high altitude.”

Importantly, the Cessna has a yoke, not a sidestick like the A330. If the speed reading is incorrect, the flight-control system’s gearing in pitch, yaw and bank channels may become inadequate and cause greater difficulties for handling.

It is important to note that speeds, descent rates and altitudes of the Citation X’s troubled flight were typical, much the same in everyday use by many fast jets. This makes Minovalov believe that the same incident could happen again.

The hypothesis that a static electricity charge can create plasma that blocks airflow is something that has previously been considered by pilots, but evidently no one else has yet reported simultaneous failure of all pitots.

Cessna responds: This appears to be an isolated event. We have had no other reports of this type in any of the 305 Citation Xs, which have accumulated some 1.3 million flight hours to date. Extensive maintenance was done on the airplane in an effort to determine the cause of the incident; however, to date we have been unable to determine the probable cause. We have obtained several system components from the aircraft, have subjected them to extensive testing and have not been able to duplicate the event. We are keeping the FAA fully informed concerning the scope of our investigation and our progress.

[SPA83]

« The crews can inherit latent conditions created by people far removed in time and space from the event. »

Slideshow: http://henrimarnetcornus.20minutes-blogs.fr/media/02/00/1981295835.pps

[FlexibleResponse]

...I would strongly suspect icing of the pitot probes that exceeded the heating capacity of the probe heating anti-ice system...

...but then again, what the heck would I know..?

[mm43]

"The crews can inherit latent conditions created by people far removed in time and space from the event"

Capt Gérard Arnoux, Capt Henri Marnet-Cornus
As clearly documented in their powerpoint presentation, latent factors were clearly involved in all incidents involving the Thales AA pitot probes. Sadly, the same latent factor in the form of 'latent heat' will ultimately be found responsible for the AF447 upset.

Even though other factors including 'why' the a/c was where it was etc. will be raised, the energy contained within water vapour should never be under estimated, as water in whatever state will always win.

mm43

[MATELO]

Just a quick one.

A "transponder" does not have to be located within the "black boxes". Just located in the same vicinity with the same robustness as them to give any potential searcher an idea where to start looking 4000ft under the ocean.

[HamishMcBush]

I was told yesterday by people that support the operation of the Rov Homer that if Airbus/Air France/Whoever really wanted to have found the FDR they would have had ships mobilised and in the search area far quicker, and they would have done a deep (c 2000m subsea) trawl with a listening device as first activity

[Deaf]

Come to think of it, if you need a marker that's detectable at low concentrations and remotely (for example, from a maritime patrol aircraft), isn't the answer a radioactive substance? It's been done for various purposes.

Vague memories of my father doing this a few times. IIRC snag is to have something with a unique signature which is both detectable and which can give a concentration (for tracing currents) a fairly short half life is required. The stuff (mostly a gold isotope) was dissolved and in the sea within 24hrs after it came out of the reactor.

[Green-dot]

The French crew also radioed about static electricity charge. It could be nothing else but them actually seeing a shining ball.



Can someone enlighten me where in the official BEA reporting the AF447 crew radioed about this issue of static electricity? The only reference about this issue I could find in the reporting is flight LH507, a Lufthansa B744 preceding AF447 by about 20 minutes at FL 350. This crew reported that `They saw St. Elmo´s fire on the windshield on the left-hand side.´

I have checked Appendix 3 of the BEA Interim report which contains the AF447 radiocommunications transcript but it does not mention anything about static electricity.


Regards,
Green-dot

[Backoffice]

Re: Pilot suspects static electricity in Citation X pitot failures


Interesting. I wonder what paint formulation/type/manufacturer was on that Citation compared with the AF A330.

Also, if the theory is correct, than it wouldn't really matter which make of pitot-tube were fitted.

[FlyBoy737800]

Guys get it through your heads - They will Never find AF447 A330

Its not in Air France or Airbus "BIG PICTURE" best interests to do this

[MATELO]

Quite a sweeping statement to make Flyboy.

I suspect though, it will be in the best interests of all pilots & air passangers world wide to discover what happened to AF447.

[manrow]

Makes sense MATELO!

[jcjeant]

Hi,

Information du 7 décembre 2009 :

Le BEA a ouvert une enquête sur l'événement qui s'est produit au cours du vol de Rio de Janeiro – Paris, AF 445, dans la nuit du 29 novembre 2009, à l'A330-203, exploité par la compagnie aérienne Air France. En effet, l'analyse de cet événement est susceptible d'apporter un éclairage complémentaire sur l'accident survenu le 1er juin 2009 entre Rio de Janeiro et Paris à l'A330-203, vol AF 447
The BEA has launched an investigation into the event that occurred during flight AF 445 from Rio de Janeiro to Paris, during the night of 29 November 2009, to the A330-203 operated by Air France. An analysis of this event is likely to throw some additional light on the accident on 1st June 2009 between Rio de Janeiro and Paris to the A330-203, flight AF 447.Information, 07/12/2009 (http://www.bea.aero/en/enquetes/flight.af.447/info07december2009.php)

Pprune ref:
http://www.pprune.org/rumours-news/397440-air-france-severe-turbulence-mayday-call.html

[ILoadMyself]

"Quite a sweeping statement to make Flyboy.

I suspect though, it will be in the best interests of all pilots & air passangers world wide to discover what happened to AF447."


Indeed it is.

[Shingles]

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 (http://insidetraveller.co.uk/blog/?p=653).

[jcjeant]

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

[rcsa]

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.

[ChristiaanJ]

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

[Carbon Bootprint]

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 (http://en.wikipedia.org/wiki/Galileo_(satellite_navigation))?

[mm43]

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

[rcsa]

Thanks, C-B. Post now deleted.

[rcsa]

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!

[Sallyann1234]

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.

[Sallyann1234]

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) ?

[ChristiaanJ]

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

[Donkey497]

@ 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!

[Sallyann1234]

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.

[oopspff7]

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.

[ChristiaanJ]

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

[Dairyground]

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.

[md80fanatic]

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?

[rottenray]

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.


.

[Graybeard]

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

[mm43]

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

[Sallyann1234]

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.

You may as well say that we should not develop new drugs to save a few lives in the West, while thousands are starving in Ethiopia.

It is up to each of us to do the best we can in our own field of endeavour.
Aviation can be made even safer by learning why each accident occurs, and every reasonable measure should be taken to continue that process.

[n5296s]

Le Monde had an article yesterday saying that the same thing had happened to another AF Rio-Paris flight on 29th November, but that since the pitot didn't freeze, the pilots were able to recover. That's about all it says. I was hoping to find more info on this thread - anyone know about this?

Link is here:

Un vol Rio-Paris rencontre les mêmes difficultés que l'avion qui s'est écrasé en juin - LeMonde.fr (http://www.lemonde.fr/societe/article/2009/12/09/un-vol-rio-paris-rencontre-les-memes-difficultes-que-l-avion-qui-s-est-ecrase-en-juin_1278384_3224.html)

n5296s

[Finn47]

n5296s, there is a thread about it here:

http://www.pprune.org/rumours-news/397440-air-france-severe-turbulence-mayday-call.html

[beamender99]

BBC News - France to resume 'black box' hunt (http://news.bbc.co.uk/1/hi/world/europe/8410375.stm)

[Nakata77]

Air France jet plunges 5,000ft in same spot as doomed flight from Brazil
Air accident experts have launched an investigation into why an Air France jet dropped 5,000 feet last month at the precise spot where an airliner plunged into the Atlantic in June, killing 228 people.

By Henry Samuel in Paris
Published: 12:58PM GMT 10 Dec 2009

Brazilian Navy divers recovering a huge part of the rudder of the Air France A330 that plunged in to the Atlantic in June 2009 Photo: AFP/GETTY IMAGES
They believe it may provide clues as to what caused flight AF447 to fall out of the sky on June 1 en route from Rio de Janeiro to Paris.
Bodies and wreckage were found but the crucial black boxes are still missing.

Related Articles
Full story of the horror on board Flight 447
Bodies of Air France flight 447 victims show no signs of mid-air explosion
Air France crash: Brazilian ship recovers three more bodies
Air France crash: plane's fin recovered
Air France plane: little hope left for survivors
Flight AF445, which replaced the ill-fated AF447, took off from Rio on Nov 29 at 5.20pm universal time and hit massive turbulence four hours later.
Air France said in a statement that the pilots "carried out a normal descent to avoid a zone of severe turbulence and to reach a less turbulent flight level".
According to French media reports, the pilots issued a mayday message while carrying out the manoeuvre as they were unable to receive air traffic authorisation for the procedure.
But instead of descending by the 300 ft that is standard procedure to avoid turbulence, the plane plunged from 33,000 feet to 28,000 feet – a drop of 5,000 feet, according to the newspaper Le Figaro.
One passenger recounted in a blog how the plane "was no longer under control", and said that cabin crew were panic-stricken. There were no reported injuries.
The incident took place around 10 nautical miles from where AF447 is thought to have gone down, in an area known as "le pot au noir", or murky cauldron, due to the frequency of tropical storms there.
Both planes came from the same Airbus A330 family and were on night flights.
Investigators believe that faulty air speed sensors may have played a role in causing the June crash. Since then all such "pitot tubes" have been changed on Air France planes. The speed sensors on AF445, however, showed no signs of malfunctioning.
France's air accident investigation bureau, the BEA, said: "The flight data could provide us with new information. We cannot pass up [looking into] such a coincidence."
The BEA is due to provide an update on the investigation into the AF447 crash next week, and the search for the AF447 black boxes is due to resume in February.

[vanHorck]

That thread already runs here: http://www.pprune.org/rumours-news/397440-air-france-severe-turbulence-mayday-call.html

[Finn47]

There will be some recommendations made when the French investigators release another preliminary report later this week, this article says, a.o. the following:

the BEA is expected to make at least three recommendations on general aircraft safety, this source said.These include extending the life of locator beacons attached to the flight recorders to 90 days from 30 days.
Regulators could also be asked to consider ordering further beacons to be attached to important parts of the aircraft structure to assist in locating wreckage in the event of a crash. Such beacons would need to be active for 30 days. Air crash cause remains unknown - The Irish Times - Sun, Dec 13, 2009 (http://www.irishtimes.com/newspaper/breaking/2009/1213/breaking14.htm)

... like I think I said earlier, extending the battery life of the pingers is the first obviously reasonable thing to do and probably the quickest thing to fix, but there needs to be regulation in place also - which will take it´s own time.

[ChristiaanJ]

Finn47
Thanks.

Judging from that article, somebody seems to have been reading PPRuNe..... it's all on the thread.

But then.... most of the suggestions are logical conclusions from the event.

One thing I was going to suggest.....

We all know what will go into a mere cellphone, nowadays.
GPS, to start with.
And we all know about digital multimeters you can throw on the floor, hard, without any effect.
And what about the last time you threw your TV remote across the room, and it still worked?

Combine enough of todays technology, GPS and all, pack it into a small near-indestructible shell that will float, mass-produce it (to get the price right down), feed it with flight data from the IFE (why not? it can recharge the batteries at the same time) and spread a dozen or so all through the aircraft.
Only needs one or two to survive.

Just tossing this out as an idea for the moment, but it would solve far more than just AF447.

Dragging the ELB into the 21st century?

CJ

[Desertia]

Air France crash remains a mystery, investigators say | IBTimes (http://www.ibtimes.co.uk/articles/20091213/air-france-crash-remainsmystery-investigators-say.htm)

[Hyperveloce]

Hi Friends,
This new interim report is available at:
http://www.bea.aero/docspa/2009/f-cp090601e2.en/pdf/f-cp090601e2.en.pdf
Jeff

[Finn47]

Second interim report published today, available here:

http://www.bea.aero/docspa/2009/f-cp090601e2.en/pdf/f-cp090601e2.en.pdf

As expected, safety recommendations are made, as follows:

1. extend as rapidly as possible to 90 days the regulatory transmission time for ULB’s installed on flight recorders on airplanes performing public transport flights over maritime areas;
2. make it mandatory, as rapidly as possible, for airplanes performing public transport flights over maritime areas to be equipped with an additional ULB capable of transmitting on a frequency (for example between 8.5 kHz and 9.5 kHz) and for a duration adapted to the pre-localisation of wreckage;
3. study the possibility of making it mandatory for airplanes performing public transport flights to regularly transmit basic flight parameters (for example position, altitude, speed, heading)

[mm43]

The original French language version of the report complete with the Annex is at:-
http://www.bea.aero/docspa/2009/f-cp090601e2/pdf/f-cp090601e2.pdf

mm43

[keitaidenwa]

The interim reports also recommends that EASA changes the certification criteria to take in account the weather conditions encountered by AF447 and the other events studied in the report.

It is interesting that they admit that not enough is known about the composition of high-altitude clouds.

[mm43]

From BEA Report
with an additional ULB capable of transmitting on a frequency (for example between 8.5 kHz and 9.5 kHz)
I suspect that return traces using an echo sounder on 37.5kHz confirmed during the last two searches that temperature/salinity changes were creating inversion layers. This would greatly hinder the chances of a weak ULB signal on 37.5kHz getting to the surface from the depths associated with this search. The use of the lower frequency in the range mentioned will alleviate the problem.

A quick read of the BEA analysis of the ACARS messages which hadn't previously been explained, tend to demonstrate the ADIRU's had a major disagreement and the TCAS took a similar view and threw its hand in. Apparently no lightning was detected by satellites during the period of this upset.

mm43

[SPA83]

On October 31, 1994, Eagle flight 184 from Indianapolis to Chicago-O'Hare, an ATR 72 operated by Simmons Airlines, crashed-during a rapid descent in severe icing conditions after an uncommanded roll excursion. The airplane was destroyed by impact forces; the captain, first officer, 2 flight attendants and 64 passengers received fatal injuries.

The National Transportation Safety Board has determined that the probable cause of this accident was the loss of control, attributed to a sudden and unexpected aileron hinge moment reversal that occurred after a ridge of ice accreted beyond the deice boots because :

1) /…/

2) The French Directorate General for Civil Aviation's (DGAC's) inadequate oversight of the ATR 42 and 72, and its failure to take the necessary corrective action to ensure continued airworthiness in icing conditions;

3) The DGAC's failure to provide the Federal Aviation Administration (FAA) with timely airworthiness information developed from previous ATR incidents and accidents in icing conditions, as specified under the Bilateral Airworthiness Agreement and Annex 8 of the International Civil Aviation Organization.

The Safety Board concludes that no airplane should be authorized or certified for flight into icing conditions more severe than those to which the airplane was subjected in certification testing unless the manufacturer can otherwise demonstrate the safety of flight in such conditions.

As a result of its investigation of this accident, the National Transportation Safety Board recommends that the Federal Aviation Administration :

“Revise the icing certification testing regulation to ensure that airplanes are properly tested for all conditions in which they are authorized to operate, or are otherwise shown to be capable of safe flight into such conditions. If safe operations cannot be demonstrated by the manufacturer, operational limitations should be imposed to prohibit flight in such conditions and flightcrews should be provided with the means to positively determine when they are in icing conditions that exceed the limits for aircraft certification. (Class II, Priority Action) (A-96-56)”

After reading that NTSB safety recommendation, we can expect the French BEA also recommends in the AF 447 report : “Airplanes equipped with Pitot probes must not fly through ice crystal areas”

[lomapaseo]

After reading that NTSB safety recommendation, we can expect the French BEA also recommends in the AF 447 report : “Airplanes equipped with Pitot probes must not fly through ice crystal areas”

You can't prohibit environmental encounters.

The regulations can assess the probabilities of such encounters and provide for tolerance of the product to some level, but beyond that the avoidance is basically a recommendation.

[memyself]

CVR and CDR recorders are obsolete antiques.

Carrying around important data on an aircraft that is ultimately only useful if the aircraft crashes is self-defeating.

The physical link between the aircraft and the data needs to be broken, to ensure the first rule of aviation is applied – fail-safe !

There is absolutely no reason why a regular data transmission of the CVR and CDR data cannot be sent from the aircraft to a central database every 15 mins or so during flight, therefore making the carrying of the data on the doomed aircraft only a back-up system.

The technology exists to do this today at minimal cost. The bandwidth required is tiny.

It would make searching for important key components of the crashed aircraft much more targeted following interrogation of data and could mean that no recovery is necessary at all, from deep ocean, high mountain terrain etc. Notwithstanding the recovery of bodies where possible.

[beamender99]

French AF447 investigators have recommendations, no answers
Friday December 18, 2009

In its second interim report on the May 31 loss of the Air France A330-200 over the Atlantic, France's BEA issued its first safety recommendations and concluded that "In the absence of any data from the flight recorders, the main parts of the airplane and any witness testimony on the flight, the precise circumstances of the accident, and therefore its causes, have still not been determined."
Investigators' inability to recover the recorders "raise[s] questions about the adequacy of the means currently in use on civil transport aircraft for the protection of flight data with the technological possibilities and the challenges that some accidents represent." Consequently, it recommended to ICAO and EASA that commercial aircraft flying over water should be equipped "as rapidly as possible" with an additional locator beacon capable of transmitting on a frequency between 8.5 and 9.5 kHz and that transmission time of the flight recorder ULBs must increase to at least 90 days from the current 30. It also urged a study into the possibility of mandatory regular transmission of basic flight parameters.
Regarding the possibility that malfunctioning pitot tubes played a role in the accident, BEA said it analyzed 13 examples of the temporary loss of reliable indications of one or more airspeeds involving A330s/A340s operated by AF, TAM, Qatar Airways, Northwest Airlines and Air Caraibes. The events occurred in highly unstable air masses in the vicinity of deep convective weather phenomena, flight levels were between FL340 and FL390, static temperature was below -40C in 12 cases and turbulence was recorded each time (ATWOnline, Dec. 17) (http://www.atwonline.com/news/story.html?storyID=18828).
"The certification criteria are not representative of the conditions that are really encountered at high altitude, for example, with regard to temperatures," BEA concluded. "In addition, it appears that some elements, such as the size of the ice crystals within cloud masses, are little known and that it is consequently difficult to evaluate the effect that they may have on some equipment, in particular the pitot probes. In this context, the tests aimed at the validation of this equipment do not appear to be well-adapted to flights at high altitude."
It recommended that EASA study the composition of cloud masses at high altitude "with appropriate precision" and modify icing certification criteria in accordance with the results and in coordination with other regulatory authorities.

by Cathy Buyck
Air Transport World

[Donkey497]

CVR and CDR recorders are obsolete antiques.

They might not be the latest thing in sexy electronics, but, they have one thing in their favour - They have a prven history of successfully doing the job they were intended to do.

There is a very good adage in engineering - "If it ain't broke, DON'T try to fix it".

It sounds nice and simple to devolve everything to ground based receivers and recorders, but........
1) Who records the information?
2) Where?
3) Who has jurisdiction WHEN something goes wrong?
4) Who pays for this service?
5) How many transmitting systems do you put on the plane to make it fail safe?
6) Do you use satelite or terrestrial radio?
7) How do you control the data volume? The comment about minimal bandwidth is simply wrong. There are according to Flight magazine figures roughly 19,000 western manufactured Large commercial jets in passenger service, plus just under 3,000 regional jets / turboprops, to say nothing of freighter conversions and Eastern bloc built aircraft. Effectively, to transmit this to a ground station, you are looking at a near real time transmission of a mandatory 88 parameters from each one. Putting the number together means that you are looking at a system acieving somewhat better than a Safety Integrity Level 4 rating.

I'm not suggesting that the current system is perfect, but bottom line - it has worked when it has had to. In the future, when we are a bit more aligned between national Aviation Authorities and national governments AND the technology fpr storing & transmitting data has improved substantially, we will likely have a land based system. But, until then.....

[precept]

Many thanks to those who made the Interim Report available. Data remains the fundamental truth most of us want to understnd. The analysis remains a variable. The conclusions still far away.

The ITCZ was a challenge before the accident. It will be a challenge and risk for some time to come.

Tom

[Tex37]

Think I need to bite at this one, although my better conscience tells me not to.

1) We are long past the days of "tape" in a modern flight recorder.

2) In the whole history of aviation there have only been a handful of broken or irrecoverable recorders.

3) To transmit data every 15 minutes is hopeless, It is usually the last 15 minutes of data that are the most important and under this ludicrous idea that would all be lost.

4) Have you any idea of how much data transfer via satellite link really costs? Most of this huge amount of data would be totally useless.

5) Do you have any idea how it would be possible to maintain an uplink in severe weather conditions and unusual aircraft angles?

6) Yes we do use the internet to transfer data, predominantly via cables/fibre networks and after that via GSM networks, I don't recall passing any GSM towers in the mid Atlantic, but possibly I should look more carefully next time.

7) Please read all the other post regarding this point.

tex

[ChristiaanJ]

Thanks Tex37!
Makes my answer simpler!

You clearly (I hope) know more about nuts & bolts engineering that you do about electronic engineering and IT system analytics. As such I understand fully your preference for metal boxes and tape reels.:D :D
It just so happens that, before retiring, one of the last things I designed and got to work was an ATE for the FDRs we manufactured.

Your electronic and IT experience clearly ended with the Commodore 64 and programs on cassette tape.

CJ

[Graybeard]

Has there ever been a cost/benefit study of CVR and FDR? Hauling 50-100 lb of hardware and wire for the lifetime of every airplane is no small cost.

GB

[ChristiaanJ]

Has there ever been a cost/benefit study of CVR and FDR? Hauling 50-100 lb of hardware and wire for the lifetime of every airplane is no small cost.
GBInteresting question, GB ....

What is the cost? Fuel to haul the equivalent of a couple of extra suitcases and some duty-free, or one more empty seat, for the lifetime of the aircraft, plus the cost of maintaining the CVR and FDR.
Less than the cost of carrying diversionary fuel, which is mostly not used... to put the weight in perspective.

What is the benefit? More difficult, because it is very difficult to assess how much and how often CVR/FDR data from a given crash have prevented further crashes (hence more hull losses and more loss of life).

Almost worth a separate thread, to avoid "polluting" this one.

CJ

[Sallyann1234]

ChristiaanJ
It should be quite possible to scope the total bandwidth that would be required for a continuous uplink system to cover e.g. the Atlantic. I'm sure that it has already been done many times and that the answer is not currently feasible, but I haven't seen it documented.

From your experience with FDR's, what is the peak data rate that a typical large aircraft records?

[Finn47]

The French are "confident" that the recorders will be found, this new article says, but the reporter "could" be slightly wrong about the search area:

an international team of experts will reduce the search area to 2,500 square meters (26,910 square feet) – a fifth the size of previous efforts.

France confident of finding Air France black boxes - thestar.com (http://www.thestar.com/news/world/article/741836--france-confident-of-finding-air-france-black-boxes)

Square kilometers would be better :}

[XB70_Valkyrie]

I was thinking about this yesterday. For crashes on land where the a/c remains relatively intact (or in one place) the current FDR designs work pretty well - they're hardened and are relatively easy to locate.

What is needed is data redundancy for when the ADR can't be found. An uplink would be a not very reliable, not very high bandwidth, not very cheap form of it.

A better idea would be to have 2 or 3 small auxiliary hardened FDR memory units which are slaved off the main FDR and attached to pieces of the aircraft that are more likely to float or be readily recovered in the event of a water impact/breakup. e.g. the tail assembly, or even attached to a float. They wouldn't have to be as large (they don't need any of the input processing etc.) or as hardened as the main FDR, just watertight and impact resistant enough to survive e.g. a water impact.

[ChristiaanJ]

... small auxiliary hardened FDR memory units.... They wouldn't have to be as large (they don't need any of the input processing etc.) ... as the main FDR....This is not a comment on your idea as such.
But most present-day FDRs don't do any input processing.
Their input processing is done by a separate FDAU (flight data acquisition unit) which then sends the data in digital format (ARINC 717, usually) to the hardened FDR.

CJ

[ChristiaanJ]

ChristiaanJ
From your experience with FDR's, what is the peak data rate that a typical large aircraft records?My experience dates a few years, so I did a bit of "informed Googling"...
The data rate tends to vary widely, depending on the age and the size of the aircraft.
64 and 128 12 bit words per second sounds familiar to me, but it's now up to 256 wps, with 1024 wps on the horizon.
That translates to about 12 kbps raw data, and for robust transmission via satellite I would say you would have to double that (more checksums, more labels, more sync).

Doesn't sound too bad, until you multiply it by the number of aircraft in the air at any one time (about 10000, of which roughly 5000 over the US, so presumably several hundred over the Atlantic).

Not to mention there is no infrastructure to handle any of this sort of data, or assure a continuous and robust second-by-second data stream...
As mentioned already, packets every 15 seconds are useless, a lot happens in 15 seconds.

Also there is no mention of the CVR in this context, which would easily account for another 12 kbps for the recording to be of any use.

CJ

[Sallyann1234]

Thank you Christiaan.
So to build a system that is reasonably future-proof you will need 100kbps per aircraft, 1000 aircraft over the Atlantic, total 100 Megabits.

The challenge will be to design and build a robust satellite-based TDMA system that can control and synchronise the individual transmissions. And an entirely new radio fit in all aircraft (with appropriate redundancy of course because the radio link will always be less reliable than an on-board recorder).

It's not impossible - given vast resources and general agreement from all the relevant national and international organisations - none of which is about to happen any time soon.

I think this puts the idea to bed.

[ChristiaanJ]

Thank you Christiaan.
So to build a system that is reasonably future-proof you will need 100kbps per aircraft, 1000 aircraft over the Atlantic, total 100 Megabits.Of course 100Mbs is nothing... it's about one 2nd-generation Ethernet link, no?
So when we talked about just bandwidth, we were barking up the wrong tree.
"The truth is elsewhere"...

You already ponted to some of the other issues...
The challenge will be to design and build a robust satellite-based TDMA system that can control and synchronise the individual transmissions. And an entirely new radio fit in all aircraft (with appropriate redundancy of course because the radio link will always be less reliable than an on-board recorder).And a huge infrastructure on the ground everywhere, to recover these data, save them, distribute them, etc. etc.

I just used my imagination a moment...
Can little "AZ Airlines", trying to operate half a dozen second-hand regional jets conscientiously on a shoe-string budget (yes, they exist and try to survive), even afford to subscribe to such a service (they never could do it on their own)? Or can they be relied on to have the facilities to receive and store the data reliably?
Their half-dozen aircraft will carry FDRs, they have to, and they're likely to maintain them as they do the rest of their equipment.
Not to mention that if they're clever, they have already tied them in with QARs etc.
What is their interest in a system that "maybe" recovers a few more data from an extremely rare accident, where the FDR itself is not recovered?????

I think this puts the idea to bed.I can think of many more reasons..... like the one already mentioned... the posited "data link" breaking down because the aircraft is in a vertical dive, for instance.

The idea mentioned by XB70_Valkyrie would be nice... were it not that a few more FDR memory units would be equally impossible to locate as the original wreckage.

Personally, I still like the dye markers.... and the improvements suggested to the ELBs and ULBs, and possibly adding more of those.

Contray to the suggestions about adding FDR units (which would mean major aircraft system modifications), they would mean minor, and largely system-independent and aircraft-independent, improvements.

CJ

[Sallyann1234]

Of course 100Mbs is nothing... it's about one 2nd-generation Ethernet link, no?

Unfortunately, no.
100Mbs from one aircraft would be easy.
But we don't have that, we have 1,000 separate data streams sent up to the satellite receiver. The transmissions can't be sent up blind from each aircraft, they would have to be synchronised and controlled from the satellite base station just as mobile phones are controlled by their network. It's a much more complex requirement. And synchronising high-speed data over long and variable-length paths from fast-moving vehicles is very difficult. Not quite impossible, but extremely difficult to do with the required 99.9999% reliability.
Only then can you combine all these data received in the satellite into a single stream to send down to the ground stations for distribution to the surface infrastructure you correctly identified.

edit: I still like the dye markers too!

[ChristiaanJ]

Sallyann1234
I may not have been 100% clear in my reply.
But I think we're already 99.9999% on the same wavelength.

CJ

[Sallyann1234]

But I think we're already 99.9999% on the same wavelength.
Perhaps even quasi-synchronous :)

[dtyedytgerdy]

A satellite uplink is only needed when there is just one aircraft in the neighbourhood. In this case the aggregate data rate for the neighbourhood is that of a single aircraft. Where there are multiple aircraft then each can broadcast its data to its neighbours. Since it is unlikely that the neighbouring aircraft would also crash, they do not need to keep the received data in hardened memory; they can store it on a regular PC and upload it to the Internet on arrival.

Arguably, the only really vital data to be transmitted are the GPS coordinates. If these were updated every 5 seconds then locating the crash site would be easy and the rest of the data could be retrieved from the black boxes. If the data were available in real time survivors could be found quicker too. The badwidth required would be much lower.

However, as already noted higher performance pingers would be a much simpler solution.

[ChristiaanJ]

The bandwidth required would be much lower.As already said, the bandwidth is not the key problem.
Your solution too would need a brand-new, very elaborate and very robust infrastructure, which currently doesn't exist.
However, as already noted, higher performance pingers would be a much simpler solution.As indeed already mentioned in the latest DGAC report.

CJ

[PickyPerkins]

dtyedytgerdy Where there are multiple aircraft then each can broadcast its data to its neighbours. Since it is unlikely that the neighbouring aircraft would also crash, they do not need to keep the received data in hardened memory; they can store it on a regular PC and upload it to the Internet on arrival.
Sallyann1234 100Mbs from one aircraft would be easy.

The above started me daydreaming of a simple system.

Could one have a "buddy system", where each aircraft is paired with a buddy? i.e. two aircraft on the same or nearby routes maybe 10 to 30 minutes away from each other are "paired". Each aircraft has its own DFDR as normal, but each also transmits its full DFDR data stream to its buddy, which records it.

On landing and confirming that its buddy is safely on the ground, the received data is deleted. Gone.

Advantages include:

(a) No other infrastructure is required. No satellites or central data handling is needed. No massive amounts of data is stored. The cost is distributed between all airlines and countries

(b) The full data stream of the downed aircraft is available immediately. Also, it might be possible to transmit just the last known position to emergency services even before the receiving aircraft lands.

(c) While I hesitate to mention this, it does cross my mind that the buddy aircraft will most times be from a different airline and maybe a different country, minimizing the possibility of any funny business in withholding, delaying, massaging, or losing the data.

There will some routes where there will be no buddy within range, but maybe only 1% of routes.

Just daydreaming. :) http://pickyperkins.home.infionline.net/pi.gif

[ChristiaanJ]

PickyPerkins,

Think it through.....

- There is no equipment in current aircraft capable of transmitting, or receiving and recording, a continuous 10 to 20 kb/sec data stream over a distance of a few hundred miles, omni-directionally.

- The FDR data in the aircraft (usually between FDAU and FDR) are perfectly useless for broadcasting... they would need additional time-stamps, sync, labels, etc. .... i.e., your scheme would require another piece of equipment for the re-coding, which currently doesn't even exist.

I can think of several other points why your scheme is impractical....

Only incremental improvements of existing equipment (such as the pingers) or very cheap add-ons (such as the dye markers) have any chance of being accepted to solve what is a very rare problem.

CJ

[Mike7777777]

4000m is a long way down. In terms of design modifications to achieve retention and transmission of information, it's all fixable ... for a price. Wreckage location: simple buoy to be released following g measurement exceeding preset level (crash). Buoy contains GPS receiver/data logger and beacon, retrieve buoy and download data logger to locate release point. ELF receiver to trigger further buoy release (assuming USN ELF system is still in operation?), ELF signal to be sector specific (but I doubt if ELF can reach to 4000m). Buoys may contain flight data loggers, data to be stored on (several) SD cards or similar.

All adds weight/cost.

[ChristiaanJ]

4000m is a long way down. In terms of design modifications to achieve retention and transmission of information, it's all fixable ... for a price. Wreckage location: simple buoy to be released following g measurement exceeding preset level (crash). Buoy contains GPS receiver/data logger and beacon, retrieve buoy and download data logger to locate release point. ELF receiver to trigger further buoy release (assuming USN ELF system is still in operation?), ELF signal to be sector specific (but I doubt if ELF can reach to 4000m). Buoys may contain flight data loggers, data to be stored on (several) SD cards or similar.
All adds weight/cost.Mike,
Nearly all your suggestions mean new and currently non-existing equipment.

Wreckage location: simple buoy to be released following g measurement exceeding preset level (crash). Buoy contains GPS receiver/data logger and beacon, retrieve buoy and download data logger to locate release point.
Yes, this has been suggested and wouldn't cost that much. Sticking a few more, and more sophisticated, ELBs (emergency location beacons) on the airframe.

But it's still as I said: "new and currently non-existing equipment", and the next aircraft going down will just happen to not yet have the equipment installed....

And no, ELF doesn't work that far down.

CJ

[poorjohn]

This thread is heading for banishment to Tech Log, so I might as well contribute to its demise.

The kind of data the FDR records is called State of Health data, on spacecraft at least. It is generally boringly repetitious and compresses nicely (losslessly, of course) sometimes using algorithms that insert values (for each channel, or parameter) only when they change by a meaningful amount. More dynamic parameters may be recorded by inserting differences between consecutive values into the data stream, each difference taking fewer bits than stating the whole value would. There's a popular silicon-based encoder (popularly called Rice encoding after one of the designers) that choses the best algorithm on the fly, no pun intended. And all this stuff exists in boxes with 1553 interfaces, since that's become popular at higher altitudes, so to speak.

I don't look at FDR data so am guessing, but would be pretty surprised if 10:1 compression wasn't a piece of cake. The costly bit would be making the box and uplink robust enough to survive a nearby explosion long enough to deliver the last message. While the normal data rate would be low, a serious event would generate full values for each parameter at the system's normal sample rate, for the duration of the event, and that would have to be preserved and uplinked perhaps over a period of several seconds.

CVR data needn't be lossless. I have nothing special to contribute in that arena, but we all realize that a minute of good-fidelity music becomes something like 1MB of mp3 data. Voice quality would be much less than that. As with FDR data, in normal flight there would be next to nothing to send.

I know nothing about what happens next, but note that Hughes and others operate geosync spacecraft with transponders dedicated to providing internet service to hopefully more than 500 customers (cited earlier as the number of transoceanic flights in some area). They're happy to support megabyte data rates for their users - far greater than needed except for mayday situations. Afaik no such service exists in the right place for oceanic monitoring, but that doesn't mean one of the maritime birds wouldn't mind providing such a capability. Hughes gets around USD80 per month per user, btw, and per the TOS doesn't appear to get annoyed until users start using hundreds of MB in a short period. I'm assuming that uplink and downlink are symmetrical for them, unless they do a lot of common-data caching on board the spacecraft. That's unlikely.

What to do with the data seems to bother people. Clearly the system would be operated by a central authority like ARINC, who could simply store it in a disk array at the satellite ground station - a giant FDR.

The thing I haven't mentioned is the uplink, because I truly know zilch about that. Hughes/Directway uplink antennae tend to be dishes around a meter dia, I think.

[Payscale]

Has it been confirmed that one FO, recent to the type, was alone in the cockpit at the time of the incident?

[HamishMcBush]

That can't possibly be confirmed, ever, unless the CVR is found and there happens to be a message from whoever was on the FD speaking aloud "Well, it's just me on my ownsome" or similar......

[Rockhound]

Payscale,
Seems highly unlikely, given that they were heading into some nasty weather.
Even the least-experienced flying crew member had 807 hrs on type and nearly 3000 hrs TT.
Rockhound

[KiloMikePapa]

But it's still as I said: "new and currently non-existing equipment", and the next aircraft going down will just happen to not yet have the equipment installed....

Which in itself is absolutely no excuse not to start working on a proper solution. I find it hard to accept that with the technology available today it seems nearly impossible to locate an airliner that went down into the ocean.

I also do not like the argument that a solution is not needed because "it does not happen very often". This accident could be a landmark accident in relation to the use of pitot tubes in high altitude adverse weather. Also: think about what happened to the BA 777 at Heathrow. Does the fact that the apparant ice accumulation in the oil-fuel heat exchanger only brought down one airliner make it any less important?

[Sallyann1234]

I also do not like the argument that a solution is not needed because "it does not happen very often".

No-one else likes it either.

But in a world where airlines are struggling to survive, it is simply unrealistic to expect them to spend huge amounts of capital and further commit to ongoing loss of revenue, in order to recover data from a one-in-a-billion accident.
It is even less realistic to expect agreement from airlines and administrations across the world on a single course of action. Their priorities are elsewhere at the moment, as can be seen in the headlines.

[ampclamp]

Not sure if its been covered but given the extreme depths that are likely involved the dye suggested may never actually make to the surface let alone anywhere near the prang.
There are thermal layers that affect acoustics I believe, so a dye solution may never appear .OK at shallows probably but them you would likely find the recorders anyway.It would certainly be helpful in many cases.
Anyone seen smoke from a large fire on a very calm day , sometimes the smoke appears to hit a glass ceiling and commence to spread out?

Given many airliners now use solid state recorders ie the fairchild 2100- series that are much lighter than the old models how about just adding to battery capacity ? All solutions will cost but suspect adding capacity in future maybe a relatively cheap option.

Live info squirts via satellite / acars for example maybe ok if they are only triggered by an event , ie engine out , manual ops by crew, excessive rate of descent, excessive g forces, loss of cab pressure etc.
Otherwise just too much info & too many flights to record.Much less to record / monitor if only triggered by an event.

Just brainstorming..

[Finn47]

There´s no reason to abandon the present recorders for a wireless system since onboard recorders already are mandatory and the cost of having them already is calculated into the business model. Just have to make them easier to find, just like is being said here.
The Boeing 787 will have enhanced recorders (CVR plus FDR in a combined unit, times two) which will record many times the data of previous recorder models and one of them will have a ten minute independent power supply. The "only" problem is, they are designed differently and collect data directly from sensors in a fiber optics ethernet data stream, which makes it impossible to retrofit these enhanced recorders to older aircraft types. Read about it here:

http://dev.flightsafety.org/asw/jan08/asw_jan08_p47-48.pdf

[ChristiaanJ]

.... Just have to make them easier to find, just like is being said here....Hi Finn,
I was already becoming aware of ARINC 767 (mostly through this thread, I readily admit!).
However, ARINC 767 doesn't yet seem to address finding "lost" FDRs...
Or does it? The article you linked doesn't mention it.

Having two FDRs at 4000m under the ocean, rather than one, doesn't improve matters, if you can't find either of them....

CJ

[Finn47]

Having two units, each with more data than ever before obviously will be a great improvement as such, but the French investigators seem to be the first to consider finding the boxes a problem worth looking into. Maybe there should be two improved ULB beacons per recorder? Provided there is enough physical free space available where the recorders are installed in the aircraft, of course.

[MATELO]

Can I just put the satellite link to bed once and for all.

There will be noway of transmitting data up to a satellite and down to an SGS (Satellite Ground Station) for recovery or use in an inquiry. Yes, the technology exists, but there are just not enough satellites up in the sky to make any sort of inroads into the number of channels that would be required. I suspect nobody will put satellites up on behalf of the air industry, so they would have to fund it themselves. On average it costs about $500m to put a satellite up into orbit and maybes 200 more may be required up there. That cost (expensive even for airline budgets) would have to be passed onto the passengers, which would make flying extremely expensive.

Secondly, placing an omni-directional (which it would have to be) satellite dish on board and aircraft would cause an immense amount of pain for any aircraft manufacturer. Also, you cant hop from satellite to satellite (like mobile phone coverage) you need to know the specific upload/download speeds and upload/download freqs for any data transmission. Any satellite on board an aircraft would have to have auto-tracking and know exactly where and when it should be looking in the sky for a satellite. Most satellites up in the sky move around and do not stay in the same location, so the aircraft would have to constantly be looking for that movement, as well as counter acting its own movement.

Yes, info could be transmitted blind, hoping the satellite would pick it up, but what would be the point in that!

[SaturnV]

Rockhound, according to the latest interim report, the actual whereabouts of the Captain cannot be determined. His body was recovered and autopsied.

Perhaps a bit more strange, none of the several CC seats recovered were occupied at the time of impact.

[ChristiaanJ]

Can I just put the satellite link to bed once and for all.I thought we already did?

Bandwidth as such isn't even the real problem, as we calculated earlier, it's the several thousands of individual little data streams, that have to be handled securely without any interruption. While technologically possible, the whole system would have to be designed and built from scratch.

As you say, the aerial is the other problem....
Satellite aerials are not omni-directional... even relatively wide-angle ones still need steering and locking on to the satellite.
Going down in an unusual attitude would most often mean losing the lock-on.
So would flying down a valley before crashing into a mountainside, unless the satellite happened to be right overhead.

So I agree with you.
Let's concentrate on finding the recorders themselves, come hell or high water (in the most literal sense...).

CJ

[iakobos]

Satellite aerials are not omni-directional
Stricto senso this is incorrect.
Eg. Iridium, Orbcomm, Globalstar, Thuraya are satellites or constellations of satellites that are accessible by portable equipment with rubberduck type of antennas.
What matters is frequency band (L, C, Ku or Ka), what it is aiming for (in terms of bandwidth/speed, which correlates to satellite power and antennas' gains) and type of orbit and height (LEO, MEO or GEO, which correlates also to latency, a critical factor for some applications).

[ChristiaanJ]

Satellite aerials are not omni-directional
Stricto senso this is incorrect.
Eg. Iridium, Orbcomm, Globalstar, Thuraya are satellites or constellations of satellites that are accessible by portable equipment with rubberduck type of antennas.
What matters is frequency band (L, C, Ku or Ka), what it is aiming for (in terms of bandwidth/speed, which correlates to satellite power and antennas' gains) and type of orbit and height (LEO, MEO or GEO, which correlates also to latency, a critical factor for some applications).
iakobos,
Stricto senso you are right.
Which is why I said it's "technologically possible".... I already was thinking of that.

But none of those systems are capable of handling thousands of 100 kbit/sec data streams simultaneously, reliably.

And try to hold the rubberduck (I am familiar with the type of antenna) upside down under an aircraft and see what ERP you get towards the satellite(s) you are relying on for those last critical seconds/minutes of data.


Something passed through my mind...

Twenty-five years ago, being able to flip open a little 'StarTrek'-like communicator open nearly anywhere in the world, an talk to nearly anybody else on the planet, would have seemed a pipe dream. (Admittedly, there are still places where you need a sat-phone, but I think you get my point.)
Now it's almost normal.

Twenty-five years from now, we'll probably expect to be able to plug in our little communicator on a plane anywhere, and instantly get connected to anybody else on the planet.
FDR, CVR and a lot of other data could ride piggy-back onto such a service.

But while FDRs and CVRs now are slowly and steadily becoming mandatory on ever smaller aircraft, even if not not on your Cessna, how many of those "data transfer" systems would in in place (and not part of the MEL) even then?

Let's stick with FDRs and CVRs (and VCRs if they can be shown to be useful) powered by the essential bus, that will stay with the disaster until the last possible second.

CJ

[SPA83]

The inconsistency of measured speeds resulting from blockage of Pitot probe is "an event that can cause victims usually with the destruction of the plane! This event can lead pilots to excessive workload which does not allow them to perform their tasks accurately or completely! “

The FAA (USA) made that affirmation several times in a document* dated September 9, 2009 using just 2 words : "unsafe condition"!

The BEA has very kindly referred to the definition of an "unsafe condition" in his report of last December 17.

What the FAA said, the European Agency for Aviation Safety (EASA) has not wanted or dared to say ... but saying it anyway.

When, in August 2009, the elimination of the Pitot probe Thales AA, fitted to the A-330 flight AF 447, is considered mandatory, EASA issued an "airworthiness directive” (AD) but claiming that it was simply a precautionary measure.

An AD for a precautionary measure, it does not exist!

When the manufacturer and EASA detect a problem that is not an "unsafe condition" but that requires a response, EASA publishes a SAFETY INFORMATION BULLETIN (SIB).

Extract of EASA document** entitled "Continuing Airworthiness of Type Design (CAP)" (March 2008). Page 39:

Only when design related issues which may lead to unsafe condition are considered likely to exist or develop, issuance of an airworthiness directive is warranted.

And

Information may be available to EASA related to airworthiness concerns on aircraft under national registers, but for which insufficient evidence exists to qualify this as an 'unsafe condition'. In such a case, the PCM [1] may elect the publication of an SIB, containing information for the safe operation of the affected aircraft.

To remove the Pitot probe Thales AA, EASA issued an AD… not a SIB.

There was therefore an "unsafe condition" that required an answer (the elimination of the Pitot probe Thales AA) !

This response came very late because the pilots of flight AF 447 had not been advised of the existence of this potential "unsafe condition"!


They were asked to accommodate the lack of pitot probes Thales AA and ensure accountability of the "unsafe condition" by applying a checklist when it is defined that an "unsafe condition" may lead the pilots to excessive workload which does not allow them to perform their tasks accurately or completely!”

* http://henrimarnetcornus.20minutes-blogs.fr/media/00/00/102670700.pdf

** http://henrimarnetcornus.20minutes-blogs.fr/media/00/00/1239787795.pdf

[JD-EE]

ChristiaanJ, there is another little detail you may not have thought of. Communications does not have to be via satellite if an alternate link can be established. That greatly reduces the demand on satellite communications. An extended cell phone technology could handle large cells from the air. If the plane is too low and falls out of the large dedicated to aircraft cells you use regular cell phone towers. Only if they fail you fall back on satellite linkages.

Of course, who is going to pay for the development of the large communications cells when no worldwide frequency allocation exists for this purpose; and, getting it will likely be a more than one decade process given how often the international frequency allocation body meets.

It's all an expensive non-starter. It can be done. It'd he fun doing it. It'd be full of interesting challenges. And it would never "pay for itself".

{^_^}

[Sallyann1234]

It's time this thread was locked, a new one opened for AF447 discussion only, and another in Jet Blast for impossible crackpot ideas.

[JD-EE]

There's always this one, SallyAnn.

http://www.pprune.org/tech-log/376433-af447-230.html

It seems to be the major repository of both crackedpottery and some good analysis. Let those with "ideas" for solutions mine that thread to see if they've presented anything new. For example, satellite FDR/CVR is very much "not a new idea." So far a cockpit video recorder linked to base by a satellite connection has not been proposed. So it's not THAT far "out there."

{o.o}

[ChristiaanJ]

Sallyann1234,

There isn't really much in the way of news on the subject anyway, at the moment, so why not let it run, as most of those interested are monitoring it?

So far I've seen almost no comments on SPA83s posts, although he's pretty well succeeded in convincing me as to the "probable cause".

CJ

[vovachan]

I think it is terribly important they raise the Titanic... er... AF447

As in the case of the Titanic, there is an experienced crew, following SOP, and then Bam!

[Unusual Attitude]

The tendering process for the 3rd search is in the closing stages with an extensive team also working on a refined search area. Not much else to report I suspect until the contract is awarded and the vessels etc are underway.

[iakobos]

Just the trace of an idea...

CVR/FDR, all well until they are located, recovered and in readable condition.
What we are looking essentially at is the location of the frame.

Relying on HF or satellite-based comms has too many limitations and drawbacks.

So, what about transmitting/broadcasting the information simply to other crafts in the "vicinity" ?
Vicinity has to be understood as 400 to 850km, being the respective line of sight distances from one plane at 30k ft to another at sea level (worst case), and two planes at 35k ft (best case).

Every craft (flying out of radar coverage that is) would have a simple and inexpensive transceiver and related antenna, VHF or UHF (the lower the best) with data storage capability. That memory would be fed in real time with position data, possibly also with some other critical data.
Transmission, continuous until "manual reset" by the cockpit, would be triggered (automatically) only in case of "abnormal/emergency" situation.

It would be received by all aircraft in the said vicinity, from where it either could be forwarded to their ACARS transmitter for forwarding, or simply stored and read upon arrival. Many scenarii are possible.
H/W cost per craft: 4 cifers.

[mm43]

@jakobos

So, what about transmitting/broadcasting the information simply to other crafts in the "vicinity" ?Excuse me, but this suggestion in many forms has been raised and debated in this and other AF447 threads for some time.

It is doomed to fail, for one the infrastructure doesn't exist, and secondly there are some very lonely Oceanic routes out there where the chances of having other aircraft within the 'so-called' range would be minimal. The Buenos Aries (EZE) to Auckland (AKL) route is one that comes to mind - 5,600NM, and for 5,000NM of the track, the chances of having reciprocal or same direction traffic in range is basically zip/zero, i.e. the sole westbound aircraft becomes the sole eastbound service on the return leg.

mm43

[JamesCam]

As to djp's suggestion about a "listener".... I like it!
Contrary to what tuj says, "listening", with modern technology, would consume far less power than regular "pings".
So pinging for a few weeks, then listening for a few months, is a good idea. It would need a new module inside the FDR and CVR (or rather inside the beacon), which doesn't exist yet, so whether there will be enough of an impetus to update the beacons, for what is a rare occurrence, is an open question.



The boxes would have to only listen say every 15 mins for a few seconds as the search vessel can carry a high powered transmitter and sensitive receiver which is operating continuously with a ping/listen cycle. if the CVR/FDR hears the ping during its listening period it immediately responds with its reply ping which is repeated for say a few minutes.

In this way, power consumption during idle periods would be minute; probably in the order of microamps, just powering a timer.

James

[Graybeard]

The CVR/FDR is a fortified box inside the frangible orange box you see on an intact airplane. The pinger, an afterthought, is bolted to the outside of the frangible box. There is no electrical nor direct mechanical connection between the pinger and the fortified box. Any improvement to the pinger would likely have to be done inside the fortified pinger.

GB

[ChristiaanJ]

JamesCam,

I read you, but I'd almost say... don't bother.
Most "passive" equipment now lasts longer than the shelf life of the battery.
Look at your kitchen timer, or your watch.
The only time they drain the battery is when they go "beep"" for some reason, which uses a few hundred milliwatts rather than microwatts.

With current technology, a receiver that listens and only answers to an interrogator (rather than to every whale passing by) will, as I said, die only when the battery dies. Always assuming the battery is designed to continue functioning at the temperatures 4000m down.

Just thought of this while typing, actually :ugh:
What is the temperature 4000m down? And what does that do to the currently used batteries?

CJ

[mm43]

@ChristiaanJ
What is the temperature 4000m down?Around +1 °C
And what does that do to the currently used batteries?Operating temperature of Lithium batteries -55 to +130 °C (depending on what designed for), but suspect lower temperature will result in slightly lower voltage and current output.

mm43

[Sallyann1234]

The boxes would have to only listen say every 15 mins for a few seconds

Microphones are delicate things.
Would the proponents of such a system kindly propose a design for a suitably small, light and low-powered receiver transducer that could function reliably under a seabed pressure of a few tons per square inch?

[beachbud]

Can anyone tell me Air France's history with regard to reducing the number of captains on a long haul flight from two to one? Is this the case? And what about US carriers? BA?

[onetrack]

For those who aren't up with underwater recovery ability, the recovery of the remains of AF-447, is most certainly within the realms of possibility.
Bluewater Recoveries have an outstanding record of shipwreck and treasure recovery - aircraft wreckage recovery is only a slight shift in their capabilities.
These people have engineered recovery vessels capable of locating and lifting 200 tons from 6000 metres .. and they have carried out projects whereby long-lost wrecks have been found, and large tonnages have been lifted from great depths in the ocean.
All the initial indications are, that the greatest depth that the remains of AF-447 are at, is around 3850 metres. It's more likely that the actual position is around 3250-3500 metres - quite within the abilities of the BR Company.

Admittedly, many shipwrecks left a decent paper trail to allow some narrowing of the search. A lot didn't, and they were still found by David Mearns and his skilled helpers (HMAS Sydney comes to mind).
AF-447 left some surface wreckage that helps pinpoint the area - Mearns and his associates have all the necessary equipment, to allow further target area narrowing, and searching with robot submarine vehicles at vast depths. All that's needed is the money.

This should be a French-Govt-initiated search, with additional financial assistance from other nations involved in pax losses. The amount required to find the important larger remnants of AF-447 appears to possibly be in the order of US$5-10M. This is piggy-bank money to Govts and nations, particularly when you see what they waste on other fruitless projects.

The Australian Federal Govt, in combination with Australian State Govts, easily found AU$4M to pay Mearns' company to find the Australian WW2 Hospital ship, the Centaur.
Mearns found the wreckage of the Centaur with ease - just as he found the wreck of the HMAS Sydney - a vessel whose location was argued and tossed about, for nearly 67 years. Many wild theories were bandied about as regards the loss and location of the HMAS Sydney, too.
I think I'd be pretty safe in saying, that if the funding was found for Mr Mearns and his operatives, they would relish the chance to find the remains of AF-447 and raise it.

This needs to be done, to put to bed, once and for all, the endless pontification, the endless rumours and finger pointing, and to define the precise reasons for the loss of AF-447. These Govts of the nations involved, as well as Air France, owe this much to those unfortunates who perished in what appears to have been believed to be (by aircraft design people) a nearly impossible event.

Bluewater Recoveries - Blue Water Recoveries are a deep sea shipwreck recovery company (http://www.bluewater.uk.com/bluewater-recoveries.htm)

[ChristiaanJ]

Thanks, onetrack.

My first question would be "IS there a wreck"?

BWR has been working on shipwrecks. Now those are usually largely in one or two pieces, even if they're associated with a debris field - I expect all of us here are familiar with the Titanic as the classic and most-often described example.

What if there IS NO wreck, but only a widely dispersed debris field?

CJ

[Donkey497]

If there's no actual "wreck" as such, just a debris field, it might make things easier to find as a debris field is considerably larger than the craft. :ok:

Where it gives you problems is that you have more individual pieces to pick up and re-assemble to get to the initial cause.:(

I guess tha main thing is to have an active search under way, rather than sit on shore and speculate.

[Finn47]

The BEA has formed an international working group to explore all kinds of ideas which would ensure better recovery of recorders and/or data during and after accident events. Most of what has been suggested here is being discussed.
Following the AF447 occurrence as well as other difficult sea recovery operations, the BEA decided to create an international working group called “Flight Data Recovery” in order to look into new technology to safeguard flight data and/or to facilitate the localization and recovery of on-board recorders. Areas such as flight data transmission via satellite as well as new flight recorder or ULB technology have been considered. It was also important to assess the cost and benefits of the possible solutions compared with existing systems. This working group met twice to perform this task.There´s quite a lot more to read here in this technical report dated Dec 22:

http://www.bea.aero/en/enquetes/flight.af.447/flight.data.recovery.working.group.final.report.pdf

[JD-EE]

Large masses of ferrous metal may be easier to detect than large masses of composites. But, if they detected wooden vessels with few if any cannons, the picture for AF447 looks nicer.

{^_^}

[BreezyDC]

Thanks for the citation, Finn 47.

Impressive for their empirical approach, methodology and processes for evaluating technical feasibility, cost and applicability, as cited in the body of the document and the appendices. Also that this was accomplished in a couple month period.

[Razoray]

I think it is terribly important they raise the Titanic... er... AF447
As in the case of the Titanic, there is an experienced crew, following SOP, and then Bam!
Yes, there are eerie similarities between the two tragedy's. Captain Smith and crew were arrogant, speeding ahead into an ice field. They were overly reliant on modern technology and considered thier vessel unsinkable......and Captain Smith was asleep far below decks when the plane....er.....Titanic hit the ice berg....

:suspect:

[robertbartsch]

...90 day FDR recommendation is confusing to me. If an A/C goes down in very deep water, would this increase the odds of retrival? On the other hand, it is probably a "cheap" mod that could be done "fast" on existing units.

I'm I correct in assuming that no one has ever tested FDR at the depth where AF447 is suspected to have gone down? ...pressures at those depths must be enormous.

[mm43]

@robertbartsch
...pressures at those depths must be enormous. Nearly 1 atmosphere for every 10 meters, e.g. 4,000m = 397.815atm

mm43

[grumpyoldgeek]

One one thing I've often wondered is why the various navies didn't get involved,
using their antisubmarine technology to triangulate the wreckage before the pinger stopped.

[grizzled]

grumpyoldgeek:
Maybe they did . . .

[mm43]

@grumpyoldgeek / grizzled

The French Nuclear Attack Submarine "L'Emeraude" (Emerald) was involved in the Phase 1 search using its sophisticated acoustic detection system, which was fine tuned during the search for maximum gain at 37.5kHz using test data developed by retuning a similar detector fitted to another Rubic class sub in the Mediterranean. The detection range was then over 3,000m, but the depth that the sub operated at is not known - "classified?"

The US Navy, US Coastguard and Brazilian Navy were also involved using hardware deployed from the surface. This consequently involved the setting up of UTC (Underwater Traffic Control) to avoid any conflict, particularly with the sub.

mm43

[Roseland]

Would it not be possible to add the GPS coordinates to the ACARS data stream?

It wouldn't appear to take up too much bandwidth.

[ChristiaanJ]

mm43,
If your "3000m range" figures are roughly in the right ballpark, we're still knee-deep in the soft brown matter.

Add slant range.
Add the fact that the pinger may be over 3000m down, in silt.
Add the directional characteristics of the "acoustic detection system".
You could pass right "overhead", and still not hear it.

CJ

[mm43]

ChristiaanJ
If your "3000m range" figures are roughly in the right ballpark, we're still knee-deep in the soft brown matter.Agreed, except as has been pointed out previously, ducting is also possible due to inversions caused by salinity/temperature. Hence the call for the lower pinger frequency to mitigate some of the potential signal loss.

The BEA report,The results of these tests identified new settings to increase the detection capabilities of the "Emeraude" interceptors sensing distance of 2 000 meters during 10 to 30 June, and extended to about 3 200 meters for 1 to 10 July.
When it comes to the directional characteristics of the acoustic detection system, I would be surprised if an x/y axial scanning method was not employed by the sub. Would leave it rather vulnerable, if that wasn't the case.

I don't think that a fuselage containing lots of composites within it is going to go to the bottom at such a speed that it is going to dig a hole and bury itself. No, more likely a very gentle bottom landing.

What is missing, is where the fuselage or parts of it landed on the surface before commencing their passage to the bottom!

mm43

[ChristiaanJ]

mm43,
Apologies, I hadn't yet read the full BEA report.

[Pugachev Cobra]

Any news on the resume of the search?

It was scheduled to February.

[CONF iture]

An association representing families of victims of the crash of the Air France A330 from Paris and Rio has again denounced on Wednesday a "crisis of confidence" with the BEA deploring in particular the "lack of transparency." (http://henrimarnetcornus.20minutes-blogs.fr/archive/2010/02/04/af447-des-familles-de-victimes-deplorent-une-crise-de-confia.html)

A Vice-President of the association, John Clemens, lamented about the lack of information on the third phase of research at sea which was to begin in early February. "mid-December, the BEA had promised he would get the families to explain the startup of this new phase. Since, there is no news, radio silence.''

[rh200]

For those who may wonder how hard it is, keep in mind how long its taken to find the Ethiopon CVR's off Lebanon, and they had half an idea where that went down.

[Pugachev Cobra]

It seems the search will resume at the end of february:

Transport aérien - Reprise prochaine des recherches de l'épave du vol AF447 ::: AEROCONTACT (http://www.aerocontact.com/actualite_aeronautique_spatiale/ac-reprise-prochaine-des-recherches-de-l-epave-du-vol-af447%7E09575.html)

[repariit]

Here is an English translation of the story linked above:
PARIS, Feb 5 (Reuters) - The search for the wreckage of Air France Flight 447, which was 228 dead in sinking down into the Atlantic on 1 June 2009, will resume in the coming weeks with an international team.

Three vessels specialized in research into shallows very uneven, ranging up to 8,000 meters deep, will be sent on an area of about 1,500 km2 located offshore Brazil, at least ten times larger than that explored in June, at we learned a judicial source.

"Our goal is that research start at the end of February, confirmed on Friday a spokesman for the Office of Investigations and Analysis (BEA), the French agency in charge of administrative investigation, which n has still not made any final conclusions on the causes of the disaster.

The tender is not finalized and the final device is not official yet, "she said.

This will be an operation almost unprecedented in the history of aviation, "very heavy and very complex to rise," said the spokesman.

A working group composed of international experts was formed in October. Air France and Airbus have a budget of ten million euros but it could be far exceeded.

A police officer will be integrated into the device to ensure that the parts that are found are placed under seal.

Two investigating judges in Paris, Sylvie and Yann Zimmermann Daurelle, are charged with a criminal investigation into the accident for "involuntary homicide and injuries".

NOT YET CONCLUSION

Associations of families of victims, which include 72 French, have instituted civil and say they fear that they hide the truth if it proves troublesome for the French aircraft.

They bring into question the independence of BEA and feel uninformed.

Until now, only pieces of the aircraft, including its tail, were rescued at sea, and about fifty bodies. The remains were stored in a research center in Toulouse.

The BEA said in its interim reports that these factors do not suggest the cause of the collapse of the device.

However, Air France was replaced after the accident probes measure pitot speed produced by the French group Thales at the request of the pilots' unions.

The latter believe that freezing at high altitude, the pitot probes can transmit false information to the computer system of the aircraft.

However, the court considers any conclusion impossible without the discovery of new elements, particularly the "black boxes" of AF447, the recording flight data and cockpit voice drivers.

"Without the black boxes, all conclusions on the probes remain in the literature," said a judicial source interviewed by Reuters.

[ChristiaanJ]

I suppose most people will get the essential from that computer translation.

One detail: "The remains were stored in a research center in Toulouse." The french word "débris" in the original just refers to the debris, or fragments, that have been recovered, not to human remains.

CJ

[Pugachev Cobra]

Reuters has an english short version for the same news:

Air France crash search to resume end February | Reuters (http://www.reuters.com/article/idUSLDE61421G)

[ILoadMyself]

They've got the FDR.

Black box from crashed Ethiopian jet is found 150ft under the sea - The Scotsman (http://thescotsman.scotsman.com/news/Black-box-from-crashed-Ethiopian.6050769.jp)

[barit1]

Crashed Ethiopian

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

They've got the FDR.

Black box from crashed Ethiopian jet is found 150ft under the sea - The Scotsman

Please see Ethiopian thread.

[aviatordom]

I know i'm not really supposed to be in this area as i'm not a professional but could someone tell me what the chances are of data being able to be recovered from the recorders if they have been in the sea that long, or is this irrelevant?

Also, what are the chances do you think as a Pilot or an Aviation Expert, Engineer, etc. of the recorders actually being found by search teams?

[ChristiaanJ]

I know i'm not really supposed to be in this area as i'm not a professional but could someone tell me what the chances are of data being able to be recovered from the recorders if they have been in the sea that long, or is this irrelevant?Modern flight data recorders use solid state storage for the data - think 'flash memory' chips.
Those are pretty sturdy, and will probably have survived even at the depths we're talking about, even if the "black box" itself is crushed or otherwise damaged.
It's been done, and there are a few specialised labs that can take this on.

Also, what are the chances do you think as a Pilot or an Aviation Expert, Engineer, etc. of the recorders actually being found by search teams?Speaking as an engineer, I think all bets are off. It's still worth a try, in case some of the wreckage is still in one place. Otherwise, with the 'pingers' now silent, it'll be the proverbial needle in a haystack, or worse.

CJ

[HamishMcBush]

Black boxes may be superseded:
Aero-News Network: The Aviation and Aerospace World's Daily/Real-Time News and Information Service (http://www.aero-news.net/index.cfm?ContentBlockID=bdf6d116-887f-4835-b8e4-792918de6270)

[ChristiaanJ]

Quote from the article linked in the previous post...
"Wi-SKY Inflight is engaged in deploying ground stations throughout North America and Europe to support the first phases of their air-to-ground network. Base stations are needed every 200 miles, which is about 125 to 150 stations in both North America and Europe".

Could somebody remind me how wide the Atlantic is, or how far AF447 was from land?

CJ

[Sallyann1234]

Not again, please! :ugh:
It's pointless putting substitute data provision where is not needed (FDR lands on the ground), instead of where it is needed (FDR falls into the ocean).

[Finn47]

Approximate minimum distances to land here, for the sake of interest, from where the aircraft probably went down:

St. Peter and Paul Rocks (Brazilian Navy station) 350 km
Ilha F. de Noronha 800 km
South American mainland 1000 km
African mainland 1900 km
Cape Verde Isles 1450 km

.... that´s guesstimating from the last known location.

[mm43]

There has been little or no detail released on the AF447 Phase 3 search, e.g. (a) what spread will be utilized? and (b) the mobilization date. News reports have indicated that Phase 3 will commence at the end of February, but I suspect that the on location date will be around 10 to 14 days later.

My suspicion is that the "Pourquoi pas?" will be the actual command vessel, carrying contracted personnel/equipment and supported by other vessels. That being the case, I can report that "Pourquoi pas?" departed Pointe-à-Pitre, Guadeloupe at 1600z 2010-02-12 with ETA Brest 1000z 2010-02-24, Av.Spd 12 KTS.

mm43

[Finn47]

There will be a BEA press conference regarding the search operations on 17 Feb, next Wednesday. No doubt further info will be released then.

Press release, 12/02/2010 (http://www.bea.aero/en/enquetes/flight.af.447/pressrelease12february2010.php)

[mm43]

The BEA held a press conference today, and the following article Air France Black-Box Quest Has Better Than 50% Chance, BEA Says - Bloomberg.com (http://www.bloomberg.com/apps/news?pid=20601090&sid=agubM1SkjpYw) has been published by Bloomberg France.

Feb. 17 (Bloomberg) -- Investigators probing the crash of Air France Flight 447 into the Atlantic Ocean more than eight months ago said the chances of finding the plane’s “black-box” flight recorders remain “well above 50 percent.”

A search that was suspended in August will resume next month with the help of computer models that have reduced the area to be scoured, Jean-Paul Troadec, head of France’s BEA air- accident investigation bureau, said today at a Paris briefing.

Without the cockpit-voice and flight-data recorders it may be impossible to discover why the Airbus SAS A330 plunged into the ocean off Brazil on June 1 while flying from Rio de Janeiro to Paris, killing all 228 people on board.

“This is one of the most complex search operations ever conducted on the seabed,” Troadec said. “‘If we don’t find the flight recorders, we won’t be able to go much further.”

Computer models run by oceanographic institutes have homed in on a zone within the earlier search area and about 10 times smaller, the investigators said Feb. 4. Data from recovered debris and satellite-tracked buoys improved their understanding of currents after previous searches ended in failure.

The area under scrutiny measures about 2,000 square kilometers (770 square miles) in water no deeper than 4,000 meters (13,000 feet).

With a budget of 10 million euros ($14 million) financed by Airbus and Air France, the BEA plans to cover the site in less than a month. Mountainous parts of the seabed will be examined by remotely controlled submarines at a rate of about two square miles a day. Flat areas can be scanned 20 times faster by sonar.

Ships Hired

The BEA has engaged two ships for the search: Anne Candies, hired from U.S-based Phoenix International and equipped with U.S. Navy sonar, and Seabed Worker, made in Norway, which will serve as a larger coordination base.

Three robot submarines will use sonar to scan the seabed and two more will explore rougher terrain.

In the first search, submarines and boats equipped with listening devices sought to detect signals emitted by the black boxes during the month that their batteries were expected to hold out. A second phase from July to August using sonar and submarines also produced nothing.

The cockpit voice and data recorders are located in the tail of the plane. About 1,000 pieces of the downed Airbus have been recovered, together with 50 bodies. The main fuselage hasn’t been found.Seabed Worker specs. http://www.seabedgroup.no/attachments/002_SEABED_WORKER-007.pdf

Anne Candies specs. ANNE CANDIES (http://www.phnx-international.com/ANNE%20CANDIES.htm)

We are still missing a lot of the detail. Hopefully more will emerge in the near future.

mm43

[ChristiaanJ]

There's an interesting PDF from the BEA on the subject, but I don't have the link.
Anybody?

CJ

[SaturnV]

NY Times article here:
Officials to Resume Search for Air France Wreckage - NYTimes.com (http://www.nytimes.com/2010/02/18/world/europe/18plane.html?hpw)

[mm43]

@ChristiaanJ

I've searched the BEA site and can't find anything new on AF447. I did find an interesting animation showing the flight paths of AF447 and other aircraft that crossed the ITCZ around the same time. I don't recall seeing it in any of the other AF447 threads.

Flight Paths of Flight AF 447 and of the flights that crossed the zone around the same time (http://www.bea.aero/en/enquetes/flight.af.447/trajectoires/trajectoires010609.html)

mm43

[cc45]

New search for AF447 is announced (in French) on the BEA website
http://www.bea.aero/fr/enquetes/vol.af.447/presentation.des.operations.de.recherches.en.mer.17.02.2010. pdf

[mm43]

Here is the link to the BEA PDF

http://89.30.127.14/fr/enquetes/vol.af.447/presentation.des.operations.de.recherches.en.mer.17.02.2010. pdf

mm43

[ChristiaanJ]

mm43,
Yes, thanks! Your 2nd link refers to the PDF I mentioned.

CJ