The second (final?) report on AF447 from the BEA is scheduled for 17th December. But in the meantime Air France isWhat's not to like? More here.

Hi,

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

floating FDR?
 

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

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

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

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

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

One presumes you are referring to the Galileo navigation system?

ChristiaanJ
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

My mistake.
 

Thanks, C-B. Post now deleted.

floating FDR
 

Hi CJ

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

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

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

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

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

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

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

I must stress though that although I fly "little planes" for fun, I have no background in aeronautical engineering. But I do fly a lot - often over ocean - on business... so have some kind of vested interest, I suppose!

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.

rcsa

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) ?

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

@ 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!

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.

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

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.

Deploying a marker prior to impact.....
 

The first thread had extensive analysis of ocean currents at the time of the crash, but we lacked clues to where the impact occurred. I'm wondering whether it would be possible, or even realistic, for a pilot under extreme duress (impact certain) to initiate a fuel dump, to leave a kerosene trail leading to the exact spot?

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.


.

Why Bother?
 

What can be found that would matter?

We already know the pitot probes were crap.

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

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

We already know a lot about the crash.

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

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

Solving mysteries is good sport, but at what cost?

GB

GB
Couldn't agree more - but in this case, "the already know", is rather speculative!

Better we find out what really did happen.

mm43

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.

Le Monde article?
 

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

n5296s

n5296s, there is a thread about it here:

http://www.pprune.org/rumours-news/3...yday-call.html

curious statement about dropping 5,000FT (i dont get whats curious about it though)
 

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.

Nakata
 

That thread already runs here: http://www.pprune.org/rumours-news/3...yday-call.html

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

Air crash cause remains unknown - The Irish Times - Sun, Dec 13, 2009

... 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.

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

New BEA Interim Report available
 

Hi Friends,
This new interim report is available at:
http://www.bea.aero/docspa/2009/f-cp...90601e2.en.pdf
Jeff

Second interim report published today, available here:

http://www.bea.aero/docspa/2009/f-cp...90601e2.en.pdf

As expected, safety recommendations are made, as follows:

AF447 Accident - BEA Interim Report No.2
 

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

mm43

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.

From BEA Report
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

15 years ago : same causes, same effects...
 

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”

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.

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.

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).
"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

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.....

Bea Interim Report
 

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