Gerard, the article does NOT suggest BEA knows where to find the recorders, any more than we all do.... read it again.

Only if we're lucky, they may still be in their original location in the tail section, which now does seem to have been found and identified.

The recorders themselves are supposed to be able to sustain a 1300g impact, but I'm doubtful about the mounting racks being designed for the same forces.
If the recorders 'came adrift' at the impact, they may be anywhere, having made their own way to the bottom, and possibly buried in silt.

mm43;
Not at all, thank you for the correction. I have to re-read the two reports from time to time and wrote from memory. Sigh.

BOAC;
The BEA Reports discuss this in various parts.

Concerning comms between the two oceanic centres about the lack of comms from AF447, yes, the BEA report discusses the comms between DAKAR and SAL (Cape Verde) on P.35 of the 1rst Interim Report. After comms between SAL and DAKAR at 03:54 the report states that DAKAR would try to contact the flight.

In commenting on the lack of communications and the raising of alarms, given the vagaries of HF communications it is not that unusual for flights to sometimes be out of communication, missing one or even two position reports. Sometimes another aircraft relays position reports to the oceanic unit. The BEA Report describes on page 68 the difficulties with HF experienced by other aircraft, (AF459)

The report does not discuss any such relayed position reports or the attempts at same. Lufthansa 507 was, as is SOP, listening on 121.5 and reported hearing nothing from AF447.


SaturnV;
I am not a communications expert but again from experience, having seen incident/event messages and sent these kinds of messages for decades regarding aircraft snags and incidents etc, ACARS maintenance messages are usually broadcast throughout an airline's communications network, (using SITA addresses, I believe). The stream of messages at a major carrier is constant - I don't know what kind of message filtration is in place to highlight more urgent messages and don't want to assume anything; the ACARS doesn't send "GO/MEET/NO-GO" messages, it just sends the text associated with the fault. I believe this series of ACARS messages would likely have shown up as teletype messages on AF's Maintenance Central, (sorry, I don't know what "OOC" stands for but I'm assuming you're referring to AF Maintenance in Paris). Flight Watch is an established, legal airline responsibility for Flight Dispatch and Maintenance alike and I expect that the messages would have been handled as such and that the true import of such messages, in the moment of reception, may not have been fully apparent.

There is some "psychology" here behind a discussion of the processes. Airline work is the very definition of "routine". People see and think what they are expecting, out of daily experience, so the "out-of-the-ordinary" takes time to sink in.

The antithesis of this point is, one is not constantly on alert for every abnormality or event which is teletyped across the system to printers and screens.

While there is an incident-alerting system in place, this wasn't an "incident" at the time of the receipt of the messages. Realization of how serious something may be from reading a series of ACARS messages is not necessarily an immediate process. Some flags may go up in maintenance if one understood exactly what had occurred, but again, it wasn't flight operations who were reading these at 03:15 in the morning. As well, there would be minimal staff on duty in these areas.

These points are neither "excuses" nor "reasons". I'm attempting here to avoid some hindsight bias by putting some flesh on the early events and queries to see how these events may have been perceived by those involved. These queries are natural and obvious now, but may not have been so at the time of receipt of the ACARS messages. That said, there are some questions to ask about HF communications especially as it concerns DAKAR, ADS/CPDLC processes in place at the time (and the failure of at least two aircraft to be able to log on), and airline flight watch processes.

"Ile de Sein" - Recovery operation update
 

Ile de Sein departed DAKAR at 2011-04-22 1810z for the Recovery Operation Position (ROP).

Edit:: ETA ROP 2011-04-26 0830z

Hi,

Those queries were obvious when the accident occured !

Air France plane that seems to have difficulties (at least they know that communications are interrupted with him) and no one thinks immediately seek if ACARS was submitted by the plane ... ?
Instead .. the management of Air France made ​​statements to the press (Gourgeon by example) that are pure speculations ....
All was proved false when the ACARS were published (not the fact of AF but because a leak elsewhere)
Can we believe in so negligences from Air France??

99,994 photos?
 

Some have wondered:

I think lomapaseo is correct about why only 6 photos were released (why would BEA release more?). But I wonder where the 100,000 number came from. I am not aware that BEA has said, nor has been quoted as saying, anything about the number of photos taken. I have seen one press article use this number, and that article was posted at #3735 (http://www.pprune.org/6404432-post3735.html) earlier in this thread. Does anyone have a reference to a BEA statement?

Actually, I proposed the 100,000 number, back in post #3163 (http://www.pprune.org/6357167-post3163.html), so it is possible that the author has simply been reading this thread. That number was a guess based on taking an image every few seconds, for several days, with several vehicles divided between imaging and sonar work. They spent more days at the site, following that post, so an estimate of 100,000 could be off by a factor of three or more, either higher or lower.

The important thing to remember, as I noted in post #3163, is that the pictures are likely taken on a grid survey over a large area extending beyond the sonar-identified debris field, and thus the vast majority probably show nothing but mud.

Hi,

Post reread .. and can you reread mine :)
Suppose IF
You are responsable of a plane (and so .. directly of all people aboard)
Someone came to you with a bad news:
We have lost contact with our plane.
What you will do ? by all means find what happened to the plane ...
You are the boss there .. so you know how all is working in your company
You know who contact .. you know all the technical stuff at your disposition for try to know what happened ..
Reminder: ACARS checked ONE HOUR before ETA !! (astonishing fact)
Instead .. you make some interview to the press .. and disseminate speculations
Are you the boss there ? or simply a spokesperson ?
From the first second communication from Air France with the press has been below any ... and they lost a lot of credit for their future communications ...
Who can be trusted after such behavior?

auv-ee, I had understood from some communications that it was closer to 15,000 images but covering an area 200m x 600m could easily produce 100,000 images.

What kind of organisation do you work for???

Not an astonishing fact at all, it's about the normal time you would start allocating resources to deal with 'incoming' maintenance issues.

And with an 'overdue' aircraft, 'maintenance' is not exactly the first department you start consulting, especially in a major airline organisation....

The small footprint of the initial sea surface debris field is probably the reason it avoided being found. Even the V/S, the largest item by far in that field avoided detection.

I have no idea if some of the low level searches were done using radar, and even if they were, there could have been sufficient sea clutter to hide other targets. Were the flights always below the cloud base? I suspect not and broken strata-cumulus can hide quite a large area in a few seconds of obscurity.

As the surface debris field spread out with the passage of time, chances of an aerial sighting lessened, and as we now know, it was a passing Singaporean registered tanker - "Ursula" that made the first sighting, which I believe was of a body.

Please don't draw any direct conclusions as to how the floating debris got to where it was found. A straight line has got nothing to do with the route taken, and as I have previously mentioned, a chimpanzee given a pencil and told to draw a line between a couple of points would probably stand a better chance of getting it right.:}

PJ2,
I understand and appreciate that there is a continuing stream of ACARS messages from numerous flights being received at AF, which are then further distributed to various points in the AF network, e.g., destination airports.

I don't know AF procedures, but in this instance, AF OCC sent an ACARS message to AF447 after 04h00 requesting it contact a control center. Would the usual AF procedure be for the crew of the receiving aircraft to acknowledge receipt of such a message? If so, would not AF OCC then be looking for confirmation of message receipt, and if there were none, try to re-contact or go on heightened alert re: AF447?

As the hours continue to go by, when does anyone at AF OCC think to look to see whether there are relevant ACARS messages from AF 447?

One possible answer might be derived from interpolating a sequence of events -- relying on the sequence in the first BEA interim report.
A.) DAKAR at 10h45 clears the French Navy's Dassault Atlantique 2 to Cape Verde, because "This was a pre-positioning choice given the uncertainty about the location of the accident."
B.) A possible interpretation of that sequence is that somebody between 10h45 and 13h00 looked at the ACARS message with the LKP sent at 02h10, and passed that information on to DAKAR. The interval between AF459 contacting AF OCC about AF447 not being in contact and the instruction to the Dassault to proceed to TASIL was about six hours.
________________

jcjeant, in this instance, there was no negligence on the part of AF OCC; if there had been survivors, and survivors were not rescued in time, then one would raise the question of negligence.

At 09h45 DAKAR called French Naval Aviation and said a plane was missing. From that time on, the response, from the French standpoint, was quite expeditious. We do not know when the Brazilian Air Force was contacted, nor when its airplane(s) first arrived in the search area. If I interpret the Naval Observatory's calculation correctly, sunrise on June 1 at 3N and 30.30W was 5:51 and sunset was 18:08. So about 2 1/2 hours of light for the Dassault if it remained in the search area the entire time.

The extent of daylight and the prevailing weather during the first day's search have not been described in any detail. The Drift Analysis group found the Brazilian search data to be sufficiently unreliable that it was not used in their calculations.

HF ACARS

I know AF447 had VHF and SATCOM ACARS capability, but it sounds like A330's do or at least did have HF ACARS.

"The A330/A340 is equipped with a standardized ACARS system that can be used by any customer,
with allowance for each customer to easily introduce his own custom features to reflect his own needs.
These initial ACARS systems have been extended to offer worldwide coverage, even in mid-ocean and
sparsely inhabited areas, using the Inmarsat facilities and HF data link, and to cover not only company
communications but also ATC services, starting with predeparture and oceanic clearances.
On aircraft delivered since 1998, the ACARS unit has been replaced by the Air Traffic Services Unit
(ATSU), which is designed to also accommodate safety-related ATC functions using the Aeronautical
Telecommunications Network (ATN), offering the majority of ATC and other communication services now
using voice, and more importantly, offering profitable migration to the ATN. The ATSU is the first unit to
host software from a number of different vendors. The same ATSU is also used on the A320 family of aircraft."

http://www.davi.ws/avionics/TheAvion...ook_Cap_30.pdf


With Canaris which is ground station 17 for HF ACARS being about 1680nm away from the approximate crash site it might have provided a tertiary path for ACARS msgs.

In general HF ACARS seems sort of sporadically used in my area, but I have received some messages from as far as 4000nm. Has HF ACARS just gone out of fashion with the advent of SATCOM?

ChristianJJ:

My mistake!

J'ai lu trop vite avant de "poster" cet article.

Et je ne sais aussi plus lire correctement! Bien noté ChristiaanJ plutot que ChristianJJ.
Je promets de ne plus me tromper!
Apologies!

Bear,

I am confused by your v/s posts :confused::confused::

So which is it?:hmm:

I suppose if one were to push this unit off the loading dock onto the concrete below, it would suffer significant damage. But, if you were to push it off the dock into the bay, it would probably be in pretty good shape. Now, wrap it into a cocoon (the fuselage) and drop it off the GW bridge and it would probably not suffer that much damage. If you review Post #s 2066, 3714 & 3729, they offer some possible explanations to this phenomenon.

As to the BEA, it would seem from their reports they have a team to help them in the investigation which includes the US NTSB. I am with lomapaseo on providing as much information as they have. The old saying "Damned if you do, damned if you don't" is at play here.:ugh:

SaturnV;
A crew receiving an ACARS message from company may or may not acknowledge, and a lack of acknowledgement at that time, would not necessarily be reason for concern. The unfolding process is, as you decribe, on pages 42 through 44 of the BEA Report. AF first began enquiries at 05 h 50 and it unfolded from there.

PJ2, "The report does not discuss any such relayed position reports or the attempts at same. Lufthansa 507 was, as is SOP, listening on 121.5 and reported hearing nothing from AF447."

This is why some of us figure the problem began well before 02:10. Now, I am a communications oriented critter. I do not seriously expect a 121.5 call once the fit hit the shan. I do expect attempted communications with other planes to get Dakar informed that I'm about to enter their control space when Dakar failed to answer. I'd try the enroute plane to plane frequency and then 121.5MHz, repeatedly. It is apparent no such attempt was made or else a whole bunch of planes in the area had failed to follow proper communications protocols or had snoozing cockpit crews. The simplest answer to this dilemma is that the problem began, probably not long after 01:35 and finally brought the plane down.

My imagination fails me when I try to describe such a problem, however.

So I am left with the question, "Why was the plane radio silent from 01:35 onwards except for ACARS messages?"

auv-ee, I'd expect more time spent looking and less time snapping pictures of everything in sight (or site.) 100,000 pictures stored in a 10 bit HD raw format would be quite a lot of data. Now, I am aware that finding computers with 207 gigabytes of spare storage is easy these days if you purchase new they might have decided to save storage and only preserved the pictures that showed something interesting.

Even supposing that is 10,000 pictures the basic answer is, "6 is enough to prove we found it. Now we need to study it all without reporters getting in the way. We will feed you when it's dinnertime."

jcjeant, the ACARS intent is to provide maintenance messages to airport facilities so that they can have necessary repair parts on hand to minimize the aircraft's time on the ground. Of COURSE they'd check it before the plane was due to arrive, and probably not a long time before it was due to arrive.

Hi,

Methink this behaviour in the major airlines will change .. cause what happend to the AF447.
Remind that actually the investigators have at today only the ACARS and some debris for speculate about what happened and those seem's suddenly of great importance (read the 2 preliminary reports)
ACARS are no more only maintenace matter now.
BTW I never read yet some words in the BEA reports about a possible "stall" of AF447 ... but I read it sooo many time in Pprune
Hope those knowledge will be updated by the black boxes datas

Yes, I've been of the opinion early on (original Rumours &News posts) that there is more to this than a simple loss of control. So may say coincidences.. I often say co-incidences of events - and most accidents are simply that - co-incidences of disparate events, activities or situations.

AUV-EE Drag & terminal fall speed
 

AUV-EE After my drag and terminal velocity theoresing (thats all it was, but should be valid for any fluid)

Water Viscosity at High Pressure and Temperature

400bar about 40 MPa

Conclusion So yes, even at 2 x viscosity unlikely to be any substantial change in drag :ok:

wing design
 

I haven't seen much discussion above about low-level aerodynamics issues - like how does wing design on Airbus affect the problems that might be encountered? I know the wing design must be very different in practice to that of Boeing - you can see this if you watch a lot of comparable landings, say a 777 vs. an A330, and the Boeing is much more stable during windy approaches, seems in all cases to land and roll. The Airbus has a definite tendency to loft down the runway. Something in their wing design favors low speed flight. So what does this say about flight when getting near the "corner"? I know these Airbuses are quite happy at 37,000 feet, but do perhaps these wings have a less forgiving performance envelope at cruise altitudes? I'm just curious, I know nothing really about commercial wing design.

What about the connection attempt to the Dakar center ADS-C system at 02:01 (Interim Report n°1, p. 48)? The report (p. 66) says, that this "first connection with the system is made by the crew". Would they have bothered with something like that if they were already in serious trouble at that time?

With an AUV there is no such thing as looking at something that has not been recorded. There is no significant bandwidth between the bottom and the surface, so everything is recorded blind and sifted through after recovery.

The camera is 2k x 2k, B&W, reported recently in a commercial article. Images are likely stored in an uncompressed format, because images of the bottom are noisy (sand/silt looks like noise) and so do not compress effectively. Dynamic range is the key factor in UW photography, because the contrast is low and the lighting is uneven, so the images would be stored with at least 16 bits/pixel. So each image should be about 2-4Mbytes (depending on bits/pixel). Not a lot of storage by today's standards. Also, the data would be dumped to a larger disk after each dive. No problem acquiring 100,000 or more pictures.

De Sitter Wing Design
 

There is (or always was) a fundamental difference between approaches... Airbus went a bit more for minimal area with very high lift devices and Boeing (usually) adopted a 'big wing', lower wing-loading philosophy.

Anotther way of saying this, that might make more sense to some, is that the 'low drag cruise bucket' is (or should be) a bit wider on the Boeing than Airbus.

However, that was a few decades ago, I imagine now, as we find with many cars for instance, that optimum design from different mfrs eventually tends to merge to a common theme and standard.

I can't really comment much on your view on low level and approach flight behaviour. I would doubt whether, effects observed were dependent on wing design.

Read the comms timelines in the earlier reports, eg. http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf [sections 1.9.1 and 1.15]. If anyone was negligent in the delay in searching for this flight, it was ATC. First a failed handover seems to have got the flight "lost" for some hours, then by around 4.30, other flights asked to try contact (AF459) and AF is alerted to try and contact. At this point this is just a lost-contact.

But ATC seems to think all is fine, because at 5.09:By 6am., AF is onto SARSAT looking for ELT transmissions (none - normally that would be good...) and talking to all the ATCs, and then ...So ATC told AF all is well (4+hrs after the crash!), and we are talking to your plane. :confused:

It then takes a further 1-2hrs (with AF reporting further concerns about lack of contact with base) before the various ATCs seem to agree that actually no one is talking to the plane, and maybe someone ought to raise an alert, but can't decide which zone the event is in and therefore who should raise alert.

Finally Dakar decides something might be wrong at7.41, 5+hrs after the plane should have contacted them...From that point, it looks like SAR starts and I guess ACARS is used to refine LKP from radio comms to direct the search.



Reminder: shortly before this, AF OCC were told that the plane was in contact with ATC over Morroco. Why would they therefore be looking at ACARS other than normal review for maintenance (probably shortly before ETA) ?

Reminder2: you (and some other posters) seem to have an idea that ACARS is some kind of aircraft tracking system, crash alert system, crash locator system, or black box subsititute. ACARS is none of those things. It's basically a messaging system for maintenance so that they know before they get the the a/c that they need the tools to unblock the aft loo, rather than having to get onto the a/c, download the messages and realise the tools they need are half a mile away on the other side of security.

AFAIK, there is noone (human or automaton) supposed to be watching the ACARS streams looking for nasty fault messages followed by loss of transmission that taken together might possibly indicate that a plane just fell out of the sky. NOone was "asleep at the switch" as someone else put it.

Could ACARS be used in this way (given hindsight of this event) ?? I'd guess possibly. But it isn't designed for it, and I think you'd have to be really clever (or lucky) about how you do the analysis (would need to be automated alert system of some sort) to get the false alarm rate acceptably low.

JD-EE;

After the crew acknowledged the SELCAL check, only a few seconds had elapsed when ATLANTICO requested their TASIL estimate but the crew did not respond.

I don't think this in itself is an indication of "trouble" at that moment, anyway (but I think it began to unfold shortly after and well before 0210).

After the P2 thanked ATLANTICO for the check, I think the P2, (who I believe was the F/O, with the RP as P1) pushed the HF radio button down, turning off the volume to the #1HF before hearing ATLANTICO's request. The request was necessary because TASIL is the FIR boundary and AF447 did not provide ATLANTICO with the TASIL estimate on first contact, which is when it's normally done. It happens and it's no big deal. And turning off the volume to get rid of the HF static noise is also normal. That's what SELCAL is for. Yet while ATLANTICO verbally requested the estimate three times, the SELCAL was never used to call the crew back.

I think AF459's experience is germane. AF459 was "37 minutes" later at ORARO than AF447. I think the phrase "at the level of" is a translation for "abeam" ORARO, as they were on a wx deviation (east of track) at that point.

The information on page 68 of the first BEA Report discusses AF459's experience with weather deviation and what they saw on the radar and what the radar settings were, such as antenna tilt, varying the gain from MAX to CAL, and which in my view were exactly correct. they were about 160nm away from the weather which is described as a "vast squall line". The animation of the tracks of all relevant aircraft is interesting - one can see AF459's deviation while AF447 neither communicated nor deviated, (as you say), yet they must have seen the same radar returns as AF459.

It's why the CVR is as important to recover as the SSFDR.

wozzo, "What about the connection attempt to the Dakar center ADS-C system at 02:01..."

Good point. I'd forgotten about that. And that would be pretty close to when the pickle fry had to have started. They had at least a few minutes to get into communications and at least tell nearby planes they were deviating.

auv-ee, arithmetic redo.

2k by 2k by 16 bits is 8 megabytes. That times 100,000 is 800 gigabytes. That is a LARGE disk to take home. (2e3 * 2e3 * 2 * 1e5 = 800e9)
Of course, that would not be one AUV taking 800GiB of pictures. That's a different storage problem. A 32G solid state drive would hold a fair amount, maybe enough to be worth a trip back to the surface. I figure I'd not put a regular hard disk in an AUV environment?

I'm not sure the ship would have had the spare terabyte drive to store the
images. (1024 vs 1000 factor plus file system overhead.)

Somebody else remarked about 15,000 images. That sounds like a reasonable number to take home. But I'm just guessing.

The quote from Phillips refers to the horizontal movement of the ship. The delay is related to the depth of the operation (and various cable parameters), but the half-hour figure is applicable at 4000m.

The heave of the ship, or payin/payout of cable, is transmitted down the cable quickly (at a speed determined by the elastic and mass properties of the cable). That is where, as you suggest, heave compensation can be applied. There are various methods possible:

Gas or active hydraulic rams/sheaves, of the sort you suggest,
Active winch (constant tension),
Bobbing crane (active or passive),
Attachment of floats to the lower tether to form an "S" section for (partial) decoupling,
Two-body deployment: depressor weight, with shorter neutral tether to the ROV,

And probably others. The latter two also decouple horizontal movement of the ship; and the last is sometimes implemented with a free length of tether, and sometimes from a second, smaller tether management system (reel) as part of the clump weight (what you referred to, right?). One reason not to use the first three methods for this job is that the constant flexing, under tension, of the same part of the cable, while deployed at a near-constant depth, can weaken the cable or damage the conductors or fibers.

I don't see any place where Phoenix says they won't use one of these methods, but I agree that their standard data sheet for the Remora 6000 does not show or claim any. Their web site does list an available ram-type motion compensator. I have no clue as to what they plan to use, and agree that delicate work with no decoupling of wave motion would be tricky.

Oops, I got very little sleep last night.

The REMUS vehicles have several nx100GB hard drives for the camera, SS sonar and other data. There is little problem with HDs in AUVs, though 250GB solid state drives are also available for more $$.

I can buy a 1TB laptop drive at our local office supply store. No one would go to sea for this work without adequate media for storing the data to be acquired. I expect they have a RAID array to hold the data from the many missions.

For reference, I am just reading a book (Project Azorian) about the location and attempted salvage of the Soviet K-129 submarine at a depth of about 5700m. In 1968 the US Navy took 20,000 film pictures of the site, with 9000 showing parts of the wreck.

Translation of Figaro article
 

The investigators have located the part of the aircraft where the recorders are placed. Reading them remains uncertain.

The mystèry of flight AF 447 could be unveiled in early May. The investigators chargéd with recovering the black boxes of Rio-Paris, which crashed June 1 2009 with 228 people on board, flew from Roissy pour to Dakar Thusrday. They have Ils met the câble ship Ile de Sein, which belongs to Alcatel-Lucent and Louis Dreyfus Armateurs and have headed off to the accident zone which they will reach in four days.

Their mission is first to raise the black boxes from the aircraft. The investigators hope to have that done in 24 hour, worse case in a few days". The Remus submersibles used by the previous expediton - which discovered the wreck - has effectively gridded the débris field and taken 15 000 photos. Remains of the nose and tail pf the aircraft , the motor[s], parts of the fuselage have been geolocated and will allow a more rapid deployment of the submersible used in this last campaign.

[from Squawk Ident

"Among the debris photographed, no trace of the black boxes but the part of the aircraft which shelters them has been formally identified and located. It is the pressure bulkhead, the wall that separates the pressurized part of the aircraft and its nonpressurized one, at the back (of the plane). On the Airbus A330, the two black boxes are fixed on each side of this pressure bulkhead."
]

"It's 50/50"

The cockpit voice recorder ( CVR) placed in front could give the investigators all the conversations in the cockpit and will allow the determination of who was at the controles and how the crew dealt with the accident. Le flight data recorder (FDR) should furnish all the paramèters of flight and will determine the scénario of the drama. If, as the investigators hope, the flight recorders are retrieved in 24 hours, a frigate of the French Navy will come from Cayenne to retrieve them, then send them to the facilities of BEA at Bourget. The investigators will remain at the site to concentrate on raising bodies. "Several dozen bodies" have been found and photographed by the Remus submersible.

It remains to find out if the black boxes can be read and have not been totally damaged by the accident. Black boxes have already been retrieved several months after an accident. They résist à shocl de 3,400 g on aircraft impact, à température of 1,100 °C for an hour in case of fire and àn undersea pressure of 6,000 mètres for six months.

In the case of AF 447, they will have been over two years at a depth of 4,000 mètres. "It's 50/50", estimates somebody close to the investigation. If the recorders can no lomnger be read, the investigators will have to raise parts of the aircraft that can help the BEA in its investigation: calculators, the position of the controls or even the maintenance recorder, situated in the hold, which contains considerable information on the flight.

PJ2 quote:
PJ2, I appreciate your desire to be dispassionate and even-handed. I thought long and hard before deciding to criticize the "Loss of VS at altitude as a causal factor" approach to this accident. I don't see this line of thought as developing anymore, it only operates in a 'restatement' mode in my view. The same old concepts are paraded out and restated. More jello nailed to the wall.
So true. But if one of these branches can be effectively discounted, then attention can go to the other branch. New thoughts can be developed.
Too often we look at things in terms of what we already know. Pilots look at questions of how could the crew have done things differently or how the airline may have put the crew in a box? Systems Engineers look at things like how the types of systems they have worked on in the past can cause such an accident? Maintenance 'Engineers' look at how particular types of systems they have had problems with might have contributed to this accident? We all have our unique viewpoints. Only when knowledge from new disciplines is added do we seem to find new corners of the AF447 puzzle.
As I stated yesterday;
I for one have delayed opening up new areas for discussions because there was an active discussion going on about how the VS might have been lost. I strongly suspect others are in this same boat.

BEA may be an agency of the French government and as such can receive political "direction" from on high, but they have their own credibility to preserve.
Their reports on the accident have been conservative, and only very recently has there been significant evidence that some of their early conclusions will have to be re-thought and corrected. (Accident location actually near LKP and possibly, the significance of ADR related ACARS messages). Their statements regarding the VS condition and their conclusions regarding how the VS came off the aircraft have not yet been disproved despite many attempts to do so and several attempts to besmirch the BEA's reputation.
If one of the proponents of the 'VS was lost at altitude' concept will provide a succinct, bulleted summary, of their points, then I am sure that the other viewpoint holders (VS was lost at impact) will have no trouble discussing them appropriately.
The problem has been that too often, the points have not been stated succinctly and instead are stated in general terms along with a variety of irrelevant cat and dog subjects. This causes many of us to tune this part of the discussion out.
VS was off at altitude proponents, please conspire among yourselves and pick a spokesperson or team to present your key points.

Why so few photos of the wreckage
 

Actually, there is probably a very simple answer.
Suppose BEA picked several interesting photos from those taken and released them to the world primarily for the purpose of showing that they had indeed found the wreckage.
Suppose then that a sharp eyed individual examining one of the pictures said "That shape over there, I think it is human remains" and then publishes that statement online. Whether or not the item was correctly identified by the poster, there would be an embarrassing and distressing scandal.

Each picture released has the potential for causing such incidents. You can bet that those photos that were released were carefully screened to be easily identified and non controversial. With the workload the BEA staff has now that data is starting to flow in, they will be in no hurry to release any other pictures.

Hi,

infrequentflyer789
Read about ATC sequences.
So we have there a suite of ATC error .. made by incompetents or lazy controllers.
They have (if all exact) a responsability of the delayed researches...
I hope those particulars will be cited at the court and punished.

That is interesting. How was the track for AF447 obtained? Im assuming the tracks from other aircraft were also from the same source. We can also see AF459 going around what must have been phantom returns on their radar. What this animation tells me is that none of the flights there had the complete picture of whats ahead. It could very easily have been any one of them in the position AF447 ended up in. (that is to say in the middle of what looks like a very active cell.) It seems to me we are tempted to question the track of AF447 simply because they were unlucky enough to not make it to the other side...

ACARS as an alerter?
 

There has much recent discussion regarding why ACARS was not referenced earlier re the loss of AF-447. Also, much discussion early in the thread on better design of DFDR/CVR boxes and pingers.

While acknowledging that ACARS is not designed to be anything other than an automated maintenance events log transmitter (and not necessarily exactly sequenced), one result I look forward to out of BEA's final report will be a recommendation that a new feature be implemented in airborne ACARs software and ground receiving computer systems:

1. Airborne ACARS to transmit a simple short standardised "I-am-alive-and this is my gps position altitude and heading" message every say 5 or 10 minutes. If the traffic overhead is low, it could perhaps be done every minute.
2. Ground based receiving computer systems to implement an automatic message parsing function to look for the I-am-alive message and trigger an alert if the next expected one or several messages are missing. The trigger could have a relaxed timing window to allow for the I-am-alive message to be pre-empted by routine maintenance messages taking priority.

This seems such a simple thing to do in software. May take months to years to certificate of course (on the airborne side, but not on the ground systems, particularly as ACARS likely does not have raw heading, position and altitude data routed to it), but would have the effect of:

a). Aiding airline dispatchers to raise an early initial alarm, rather than wait for ATC to coordinate of reports of missing scheduled communications.
b). Ensuring search resources can be mobilised faster, with greater certainty to a smaller search area.

ACARS is not designed for this function, but it is the one reliable system we have on board today that could be readily adapted to include this capability, having continuous immediate access to reliable global communications.
The ground based message parsing and triggering would be relatively trivial to implement.

Such a capability, could be relatively easily developed, requires no more boxes or systems in the aircraft, and may not even require any wiring changes if the (optional, preferably desirable,) gps position, altitude and heading data are available on any of the data buses brought to the ACARS system.

NB: This concept is much much different from suggestions way back early in this thread that FDR data be transmitted over ACARS. This would require high bandwidth, which ACARS does not support.

What I am suggesting is an ESSENTIAL requirement for ONLY for a standardised, very terse, I-AM-ALIVE code. Loss of one or several sequential messages is what would trigger an alert.

Any other data transmitted could be optional, depending on aircraft configuration and data availability to ACARS. I am suggesting only position, heading and altitude as minimally desirable, as together they enable a reasonably accurate estimate of LKP. VS/TAS/GS could be roughly and sufficiently interpolated from this, particularly if transmissions at the one minute or so level could be supported.

The problem started on AF447 and finished there!
 

Folks,

I think it is time to reverse the time machine and go back and take a closer look at what actually transpired between AF447 and ATLANTICO at INTOL.

Refer to the AF447 thread where many moons ago I laid out the obvious discrepancy in the waypoint timings provided to ATLANTICO for SALPU and ORARO. ATLANTICO had good reason to query the aircraft and at the same time request the ETO TASIL at the FIR boundary.

Now why were the timings so obviously incorrect???

When DAKAR requested a FP for AF447, the Virtual FP information provided to DAKAR by ATLANTICO was an estimate for TASIL that they (ATLANTICO) had created. Were ATLANTICO too busy to pursue AF447 using SELCAL and check with DAKAR that the a/c had made contact with them at the FIR boundary? I doubt it. They just assumed that DAKAR OCEANIC would get comms with the a/c at some stage of its transit through the DAKAR FIR.

Machinbird;
Yes, understand. No criticism intended of your post because I believe the view expressed is on the right track, not because "I" don't like the other theory, but because the evidence has not led us to that conclusion.

If the evidence for loss of the VS sometime before impact, (and if not at altitude as the precipitating event, why is any other scenario important short of 'attached at impact' ?), were incontrovertible and argued as such, no problem, but it has not and the pursuit is, as you state, no longer productive in terms of finding out what happened and how the aircraft actually hit the water.

What is the simplest explanation for the seeds of this accident? Where did the series begin? What failed and where in the series to intervene in the causal paths and permitted "the next step" to proceed to completion?

mm43;
Yes, I think so. Missing comms is initially, not that big a deal on the Pacific, Atlantic or Arctic. It is slowly changing as ADS and CPDLC installations grow.

But this is the sense of "normal" I was meaning to convey about comms; - when no scent of something wrong is sensed by anyone, at that point.