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AF447

Old 16th Jun 2009, 22:51
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That a portion of the LDMCR has been recovered is, in itself, about as relevant as the fact that a spoiler panel has been recovered (actually, less so).
I thought that the inference from the photo was whether it was occupied and whether this was indicative of no specfic CC warning about turbulence.

I don't know the answers to this but I had sensed in the thread that is why it was being discussed.
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Old 16th Jun 2009, 22:53
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I'm new to this forum, so hello to all gentlemen.
Some tiny details in the ACARS message list presented by Air France suggest that at least part of it may have been manually edited, a process prone to human error. Looking closely at it, I found a discrepancy between the warning labelled "NAV TCAS FAULT" and the associated JASC code. This code, 3443, stands for NAV/DOPPLER SYSTEM in the JASC classification. However, the a/c was not Doppler equipped. TCAS should be coded 3445.
All other codes appear correctly related to their labels.
Whatever explains this discrepancy, including a possible use of a slightly different classification by Airbus, I believe it should be considered doubtful that a TCAS FAULT warning ever happened.
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Old 16th Jun 2009, 22:58
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JD-EE;
So both water and ice will work.

. . .

So one major postulate for answering the question above is whether there was some form of filtering between the radar return and the crew that made them unaware of the magnitude of the problem they faced.
Re water and ice, yes, ice crystals less so.
Filtering/attenuation/antenna tilt/gain...all are areas which modify the return signal being displayed. The 777 radar does a lot of this work but I am told but I don't know anything about it other than what can be read in the B777 AOM.
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Old 16th Jun 2009, 23:01
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PJ2

Although your specific post has diappeared: good points. Well taken. At this side full of good intends a well. Regards, CV

Last edited by Dutch Bru; 16th Jun 2009 at 23:16.
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Old 16th Jun 2009, 23:12
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Originally Posted by lomapaseo
I thought that the inference from the photo was whether it was occupied and whether this was indicative of no specfic CC warning about turbulence.

I don't know the answers to this but I had sensed in the thread that is why it was being discussed.

Are you confusing the photo of the F/A's jump seats with the belts stowed to that of the Crew Rest area?

In any case, none of the photos prove anything about turbulence or crew awareness.
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Old 16th Jun 2009, 23:14
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Quote:
Originally Posted by Lemurian
Look, these messages are just the picture until 0214Z. What happened next is pure speculation.

BOAC replies: - maybe I'm not expressing myself clearly. I'm looking UP TO 0214Z, not 'next'. The point I am making is that there MAY be a case for saying the cabin was INTACT until the descent warning, which would cast doubt on the "the fin fell off and tore open the fuselage" line. In fact, how long would it take for the cabin to achieve 1800fpm? Could they even have been descending before the 0210Z message stream we have?

There have been contradictory, vague and confusing descriptions of this 0214z warning and it would be helpful if one of the experts would clarify exactly what it means.

A long, long way back in this thread, somebody suggested that this warning indicated a rate of descent of the a/c great enough that it would OVERTAKE cabin altitude before reaching ground level. In other words, if the a/c continued descending at the same rate and unless cabin altitude fell at >1800fpm, pressure outside would end up greater than pressure inside.

IF that is the true meaning of this warning, it indicates that two things were true at 0214z: (1) the cabin was still intact, and (2) the a/c had just started to descend at a rate sufficient to trigger the warning.

Could one of the experts please confirm the meaning of this message?
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Old 16th Jun 2009, 23:21
  #1747 (permalink)  
 
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Quote:
That a portion of the LDMCR has been recovered is, in itself, about as relevant as the fact that a spoiler panel has been recovered (actually, less so).

I thought that the inference from the photo was whether it was occupied and whether this was indicative of no specfic CC warning about turbulence.

I don't know the answers to this but I had sensed in the thread that is why it was being discussed.
lomapaseo,

If that was the inference then sorry, I missed it. To be honest I don't think there are any conclusions about warnings to CC about turbulence that could be derived from whether the LDMCR was occupied. One might conclude that, if it was occupied, the CC were not in the process of preparing for an emergency landing, but that would require the assumption that the conditions existing would have permitted the CC to exit the LDMCR. With so many unknowns we don't know if that was the case so the occupancy of the LDMCR or not in itself doesn't tell us much.

ELAC
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Old 17th Jun 2009, 00:22
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341115

If someone could provide the exact terms of the A330 Troubleshooting Manual where it is stated that the code 341115 refers to all pitot probes in disagreement (meaning the inexistence of at least two probes returning compatible airspeed reading) this would be "case closed".
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Old 17th Jun 2009, 00:42
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Lost-in-Saigon

Are you confusing the photo of the F/A's jump seats with the belts stowed to that of the Crew Rest area?

Yes

In any case, none of the photos prove anything about turbulence or crew awareness.

Agree at this point
Thanks for de-confusing me
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Old 17th Jun 2009, 00:49
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ATA 34 under 11/15

Don't know about case closed (is it ever?)..

But everything Air France has said (more than one might expect TBH), tends to point towards that very interpretation.
Well, a simple reproduction of the ATA 34 under 11/15 (or whatever describes the related warning) confirming that ALL pitot tubes were disagreeing would end all speculation going on here.

Pitot Probe 1, then 2 and at last 3 being clogged or whatever other order of facts, provided that this message really applies to at least two getting 'out of service", would clearly explain almost everything that went on later.
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Old 17th Jun 2009, 01:04
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Well, a simple reproduction of the ATA 34 under 11/15 (or whatever describes the related warning) confirming that ALL pitot tubes were disagreeing would end all speculation going on here.
No, but it would answer one question among many.

Mere bad readings of pitot tubes BY THEMSELVES are insufficient to cause a crash. There have been a number of cases of pilots clearing storms, thawing tubes, etc. However there are more questions which are unanswered in this case than we have answers. When looking at some details we must be careful not to confuse them with the big picture
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Old 17th Jun 2009, 01:08
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Wow.. I go to Paris for the airshow for a few days and when I come back this thread has grown like kudzu in south Georgia.

As I meander through the questions and answers, the explanations and some of the assertions, I am reminded of an interview I sat in on with Diane Vaughan, the professor who wrote the Challenger Launch Decision. The interview took place after Columbia broke up.

Vaughan said that when she began her background investigation of what happened, she fully expected to find ineptitude, cover-ups and 'skulduggery' (I will always remember that one). She said what she found was highly experienced, high intelligent, highly committed, highly educated, hard working people who were doing what they believed to be right and within the margins.

I guess my point is some want to suggest there is stuff to be covered up, the crew did irrational things (fly into the teeth of a monster storm system), the airplane has serious flaws that everyone knew of, that a system like FBW is replete with flaws and failures, that some authorities are hoping the FDR/CVR won't be found so flaws can't be revealed.

Sometimes you just have to step back, take a deep breath before continuing to sift through the relevant and informed along with the other stuff.

This one has been a real education.
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Old 17th Jun 2009, 01:27
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I guess my point is some want to suggest there is stuff to be covered up, the crew did irrational things (fly into the teeth of a monster storm system), the airplane has serious flaws that everyone knew of, that a system like FBW is replete with flaws and failures, that some authorities are hoping the FDR/CVR won't be found so flaws can't be revealed.
Yes, all so far with little, if any, evidence...

I suppose the most that could be said from that list, is that the pitot probes may well have not been fit for the purpose they were put to that night.
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Old 17th Jun 2009, 02:25
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ACARS

I have gone back again to look at the ACARS messages. I posted in #843 on 9th June that at least some of the messages had been truncated, but not many people seem to have picked up on that fact.

Now, looking at the format of the printout, what else can be discerned?

1. the listing seems to be a subset of messages extracted from the total acars info available for AF. The selection criteria appear to be a) by reg no. FGZCP and b) by time - 120509 thru 010609

So someone has run a programme that does "show me a list of all acars messages received from FGZCP between 150509 and 010609

There could well be other filtering applied, as I am led to understand that other things are reported on acars on the normal takeoff/landing event.

2. The list appears to be displayed in earliest flight first order, and latest message first within flight. This seems slightly confusing, as you have to then read down the printout from page 1 for a chronological sequence of flights, buit then having found the flight you are interested in go to the bottom of the list for that flight and read backwards to get a chronological sequence of messages.

3. The timestamp displayed as part of the messages is not the timestamp used for sorting the messages into the displayed order, as some messages "appear" to be out of sequence. Maybe there is a separate undisplayed timestamp such as arrival time, and maybe the messages are not even transmitted in chronological sequence - some messages could be deemed more important than others and therefore jump the transmission queue.

4. The appears to be a "trailer" message at the end of a flight. This is the message with just / from what i assume is the previous flight, along with the PFR message from 2013. Maybe someone can decode that?

Therefore my assumption is that the first 27 pages contain messages from previous flights of that airframe. What puzzles me is that the list seems to go on for 256 pages, implying that there are many more messages following on from the ones we have seen. It is certianly an odd coincidence that the list would end exactly on a page boundary. I would also add that 256 is one of those "magic" numbers in computers, and could just indicate that a lazy programmer couldn't get the code right to count the number of pages that were going to be printed.

All this simply leads me to caution on attributing too much authenticity to these messages

Last edited by stickyb; 17th Jun 2009 at 05:10.
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Old 17th Jun 2009, 02:30
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ACARS information.

It seems convenient that we see two ACARS messages concerning AF 444 on the 31st of May, preceding any messages relating to AF 447 -

However we see no messages relating to any other flight, post- the supposed 'last message' from AF 447 at 02:14z.

This leads me to question whether or not there were any further messages from 447.

Surely it would put it to rest, if we for instance had seen the string of messages from AF447 cease, and the next batch from another flight begin (as was seen with the messages from AF 444 leading into the AF 447 messages).

To whatever degree these messages have been truncated, I can't be sure we're getting the complete story from beginning to end.

These are pages 28, 29 isolated from list of messages 256 pages long.

What is shown on page 27?



JLL.
JLL,

I think you're wandering over into conspiracy theory territory here. First off, to my knowledge the ACARS message report that we've seen is not a document released by an official source within Air France or BEA but rather was printed off by someone with access to the AIRMAN system who then made it available to the media. It is that individual who will have chosen what they considered relevant and what not, not any part of the officially involved parties.

Second, if you review the page headers you'll notice that they they include a block that reads "Materiel: AV FGZCP REG". I'm no expert on the system but a reasonable guess is that the output listed below is a result of a search for messages transmitted by FGZCP and hence messages from other aircraft would not be shown. If they were you might see some interspersed between FGZCP's 26 messages. Obviously there would also be no messages to show subsequent to the last one received. As the last message on the sheet coincides with a page end we can't be sure that we are seeing all that there is, but particularly given the unofficial nature of the source can you think of any reason why they might have withheld anything they considered relevant?

Last edited by ELAC; 17th Jun 2009 at 08:33.
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Old 17th Jun 2009, 03:19
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This is getting pretty funny. I dont recall seeing a fault message 34-11-15 but several pages back, someone posted a listed of components and their related AMM references and said that they were fault messages. I've reproduced the first page of eight pages of the AMM reference 34-11-15. As you can see, this tells you how to replace the Pitot probe.
These fault messages are for use by maintenance personnel as a starting point for troubleshooting. Different fault codes give different clues and different starting points in the troubleshooting process. Nobody stands around trying to interpert them.
I would hope that nobody thinks that this aircraft seriously produced 256 pages of faults. The airplane would have to have been falling apart one component at a time. There were probably endless streams of messages to the maintenance control department from all over the world that night and these messages wound up on these pages.
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Old 17th Jun 2009, 04:15
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341115 again...

JetDoc,

In post 41 you will see the list of the 24 ACARS messages

In the third from bottom to top you will find the wording "34111506", among other things, which, as already discussed here, relates to the ATA code 34-11-15 which directs to the pitot tube (-s ?). The 06 relates to the flight phase (cruise)

I don't know if "Troubleshooting Manual" equals "Maintenance Manual". So in the "Troubleshooting Manual" - if it differs from the "maintenance manual" - maybe there is some other reference linked to the pitot tube(s) - in other words, linked to the same code 34-11-15.
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Old 17th Jun 2009, 04:21
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Clarification on a couple of ACARS assumptions?

I hope this will be taken as intended - as an anti-speculation post.

1. Is it really safe to assume that all three pitot tubes were giving false readings? All three might disagree - but that would also be true, would it not, if only two were giving false readings and the third was still functioning normally in all respects? In the event it probably does not matter, since the computers are going to report a three-way disagreement and toss it to the pilots in either case...I just caution against stating flatly that all three pitots failed. We don't know that.

2. The cabin altitude warning seems equivocal. Plane decompresses - or - plane rises 2,000 ft. in 20 secs. in a convective updraft - or - plane drops 2,000 ft. in 10 secs. in a convective downdraft - or - plane ascends/descends rapidly for some other reason. Would not any rapid altitude change in either direction that exceeded the pressurization/venting system's ability to keep up lead to this warning?
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Old 17th Jun 2009, 04:28
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valid airspeed reading

1. Is it really safe to assume that all three pitot tubes were giving false readings? All three might disagree - but that would also be true, would it not, if only two were giving false readings and the third was still functioning normally in all respects? In the event it probably does not matter, since the computers are going to report a three-way disagreement and toss it to the pilots in either case...I just caution against stating flatly that all three pitots failed. We don't know that.
We could ask a simpler question: Does the code 34111506 in the ACARS message set mean that there wasn't a valid airspeed reading/value availabe ?
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Old 17th Jun 2009, 04:34
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ACARS data origins

Publicly known ACARS messages originate from a June 4th (evening?) "French television station France2 produced the ACARS messages from the last minutes of the flight of the A330. The data was clear on screen and has since been reproduced here."

Flight 447 was lost on June 1st. So we have:
* 3 to 4 days interval between loss of Flt 447, and appearance of the public ACARS data.
* The data 'release' involved both error-prone visual/manual transcription from a screen capture, and a mainstream media source.
* At least one potential factual error has been identified in the data.
* The 'known' ACARS data is very likely incomplete - it omits non-maintenance streams, and possible records prior and subsequent to the available ones.
* There is no formal provenance to even the 'known' ACARS messages. I do not have a transcript of the TV station broadcast, so don't know the actual wording used. I must consider that there might have been commentary to the effect of 'typical', 'representative', etc in conjunction to the on-screen text. In any case, TV stations are under no legal obligation to be truthful, and we know nothing of their source.

One thing I find a little odd. All the copies of the 'ACARS text' I can find are images, as opposed to plain text files. Also, someone has gone to the trouble of creating those images complete with faint alternate line shading, as if they are direct scans of line printer output on typical fan-fold tractor feed paper. Yet these are supposedly manual transcriptions, from the screen of a TV news item?

I found two sources of this image:
http://img197.imageshack.us/img197/3410/acarsaf447e.png
http://www.eurocockpit.com/images/acars447.png
They are substantially the same image, but they are not identical. Examining the images closely in photoshop, via a red/blue overlay (see http://everist.org/flt_447/a-b_compare_flat.png) determines:
* They are exactly the same x-y size.
* They are identical in almost all pixels, except for three points of difference, where characters have been altered, added, or moved. (See yellow shaded items in my image.)
* Both versions very likely created by the same source, due to exact pixel correspondence of the non-aliased font used. One presumes that one or other version is an update, with corrections as errors from the visual transcription are noticed.
* They are most definitely electronic image constructions, rather than processed scans of paper documents. There are zero image/colour defects of the type resulting from scans, also the shifting of the "CTL SEC 1 FAULT" item could not result from a scan error.
* Both are identical in the "NAV TCAS FAULT" and the associated '3443' JASC code, which is suggested should read '3445'. (Shaded blue in my image.) We do not know if this is a transcription error, or if the original code really is '3443'.

From the above, one can conclude that the known images really are the product of a manual transcription from a TV frame-grab, as opposed to actual printout scans, merely *said* to be transcriptions to protect someone from charges of leaking confidential documents. Thus the TV station broadcast was the original source.

Now, I'm not suggesting that the known ACARS messages are a fabrication. However one must logically bear in mind that lacking a formal release origin, they easily _could_ be a fabrication.

Worth remembering, given the comments from several official sources that the flight recorders are unlikely to ever be found.

---Some previous relevent posts---
http://www.pprune.org/rumours-news/376433-af447-87.html#post5001546
Being curious about the source of the two pages of ACARS messages, which are labelled 28/256 and 29/256, I looked around to see where they originated. Amazingly, this seems to be it:
http://www.flightglobal.com/blogs/unusual-attitude/2009/06/af447-accident---icing-pitot-t.html
So the crucial text on which everyone is basing analysis, was hand copied from a screen visible during a TV interview! Furthermore I gather from other comments here, that this is just one ACARS stream (maintenance messages?) of several. Also that it isn't publicly known for certain that these two pages are even all the relevent messages from that stream.

http://www.pprune.org/rumours-news/376433-af447-89.html#post5002147
"I'm new to this forum, so hello to all gentlemen.
Some tiny details in the ACARS message list presented by Air France suggest that at least part of it may have been manually edited, a process prone to human error. Looking closely at it, I found a discrepancy between the warning labelled "NAV TCAS FAULT" and the associated JASC code. This code, 3443, stands for NAV/DOPPLER SYSTEM in the JASC classification. However, the a/c was not Doppler equipped. TCAS should be coded 3445.
All other codes appear correctly related to their labels.
Whatever explains this discrepancy, including a possible use of a slightly different classification by Airbus, I believe it should be considered doubtful that a TCAS FAULT warning ever happened."

http://www.pprune.org/rumours-news/376433-af447-89.html#post5002195
"There have been contradictory, vague and confusing descriptions of this 0214z warning and it would be helpful if one of the experts would clarify exactly what it means."

http://www.pprune.org/rumours-news/376433-af447-89.html#post5002268
"What is shown on page 27?"
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