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Hello,
From a hull/system breach, or, more likely, the bleed supply insufficiency (idling/compressor-stalled/flameout engines). But i do'nt have a good knowlege of those buses. |
A somewhat interesting article has appeared in Le Figaro in which it is claimed that the BEA will not be contributing to the Phase 4 search due to get underway from Recife in February 2011. The €11,000,000 cost is to be shared equally by Airbus and Air France, and the Remus AUVs will be operated from a smaller vessel than in the Phase 3 search. The article indicates that the "Alucia" (formerly Ifremer's "Nadir") will be the support vessel, and that the search will begin in the north of the 40NM radius probability circle and extend south to the Last Known Position.
The vessel will only be equipped for the search and mapping phase and planning for the recovery phase will be made once the wreckage has been located. It's anticipated that there will be 3 rotations of the vessel, each of one month from its base at Recife, to cater for mandatory crew changes, providoring and bunkers. An interesting (though unverifiable) comment was made regarding discussions the BEA has purportedly had with the Russian Army, in which the Russians stated that statistically most crashes happen within 5-10NM of the aircraft's last reported position, and those crashes occurred "at the end of a vertical drop and a spiral path". |
mm43
I thought that WHOI was given the task of finding AF447 in February? But I checked their web site and they have nothing scheduled for that month. So the article, in Le Figaro, seems to confirm that there has been a change of plans, and that the assignment has been given to someone else? :hmm: |
will begin in the north of the 40NM radius probability circle and extend south to the Last Known Position. |
promani
I thought that WHOI was given the task of finding AF447 in February? wes_wall .. will begin in the north of the 40NM radius probability circle and extend south to the Last Known Position. |
If the search is only North of LKP is indeed true, then they are absolutely discounting the possibility of AF447 losing control in Normal Law either at or slightly before the ACARS sequence.
From the BEA Perpignan accident report: When the stall warning sounded, the Captain reacted by placing the thrust levers in the TO/GA detent and by pitching the aeroplane down, in accordance with procedures. The nose-down input was not however sufficient for the automatic compensation system to vary the position of the horizontal stabilizer, which had been progressively deflected to the pitch-up stop by this system during the deceleration. The Captain controlled a left roll movement, caused by the stall. The aeroplane’s high angle of attack and the roll movements generated asymmetry, and a speed variation between ADR 1 and 2 appeared. This increasing divergence caused a rejection of the three ADRs by the FAC then the ELAC. The flight control system then passed into direct law. It is likely that the crew did not notice this due to the emergency situation and the aural stall warning that covered the warning of a change of flight control laws. If no recovery, the aircraft would be found close to LKP, even possibly South of LKP. |
New search/La Figaro
My French was never good enough, but Google's translation is:
from La Figaro: The research will once again take place in a circle of 40 nautical miles (72 kilometers) around the last known position of the flight AF447. The goal is to finish browsing north of the area that was observed last spring and then systematically sweep the entire area back down south and the last known position of the aircraft. Many experts believe that because the wreck lies further south. |
In close association with the first Le Figaro article, there was a very interesting article regarding who is participating in the search...... and who isn't. See Link: Le Figaro - France : Nouvelle campagne mi-février pour retrouver l 'AF 447 Please pardon the rough Google translation:
INVESTIGATORS DENOUNCED THE WASTE OF PRIOR RESEARCH By Fabrice Amedeo 17/12/2010 The Bureau of Investigation and Analysis (BEA), who led the first three campaigns, loses his hand on the ground. It is the U.S. Woods Hole Oceanographic Institute who took control of operations. Operation Last Chance sounds a bit like a disavowal previous . Three missions have been organized in the South Atlantic. The first, launched a few hours after the tragedy , helped recover bodies and debris from the aircraft. The second, launched one month later, tried to capture the signal of the black box before it goes out. The third, organized last spring, has combed the area defined on the basis of studies rétrodérive. This method is based on the positions of bodies and debris recovered and to define the position of the wreckage through a study of the currents. In vain ... This time, the Bureau of Investigation and Analysis (BEA), who led the first three campaigns, loses his hand on the ground. It is the U.S. Woods Hole Oceanographic Institute who took control of operations while on-site coordination will be ensured by a framework of Airbus. "The BEA is the guarantor of the independence of research and investigation, said a close case, but we will work differently." Meaning: more efficiently. Interviewed by Le Figaro, BEA refuses him, to comment and explained that, for now, "nothing is finalized." The Alucia that will be equipped submarines Remus. During the last operation, boarding submarine ROV has indeed squandered the funds made available by Airbus and Air France. "They have not been once to the sea," laments an investigator. This material was indeed expected to go up the black boxes and pieces of wrecks that have never been located. Reportedly, the ROV had been rented at exorbitant prices to the Navy, for diplomatic reasons, on the advice of pressing the Embassy of France to the United States. "Officials no idea what the subsea intervention have interfered in the investigation, expressed regret one of its members. This proved disastrous. "Sonars onboard were also used. "They swept plains on the outskirts of the search area, said an investigator, but were never able to rake the area with high probability which is very mountainous." The study methodology rétrodérive also ineffective in this region of the globe where the currents are very irregular and at times of the year (June) where there is not mainstream but rather a gradual rotation their direction. "The models had forecast 0.1 knot of drift, an investigator said. Once there, we realized they were ten times stronger. "Within the survey, were also strong voices in denouncing the methodology of the Bureau of Investigation and Analysis (BEA), which wanted to keep hold of the studies and did not adequately take into account the findings of a team of Chinese scientists from the Massachusetts Institute of Technology (MIT). Air France and Airbus have promised that this time, there would be no squabbles of ego and the systematic sweep of the area increased the chances of success. |
The study methodology rétrodérive also ineffective in this region of the globe where the currents are very irregular A study of the backtracking methodology reveals it was ineffective in this region of the globe where the currents are very irregular Irrespective of the politics involved, the BEA will assume responsibility for any recovered wreckage once it has been raised to the surface. |
gossip
mm43;
I thought you had consciously ignored the second article in lefigaro.fr. We have seen more stories from Fabrice Amedeo picking up gossip from unnamed sources 'close to' the investigation. Fascinating read, to be taken with more than a grain of salt, IMHO. regards, HN39 |
More gossip
HN39;
I thought you had consciously ignored the second article in lefigaro.fr. Fabrice Amedeo pour - Non! Non! Ce n'est pas, "Trois missions ont été organisées dans l'Atlantique Sud." Mais il est, "Trois missions ont été organisées dans l'Atlantique équatorial du Nord." mm43 |
New Pitot Warning
. . . . . . . Airbus has discovered that in some cases two Pitots can give matching, incorrect speed data, which could lead pilots to re-engage autopilot prematurely . . . . Read more: CBC News - World - Airbus gives new warning on speed sensors |
ACARS Message Timing Anomalies
The ACARS messages are intended to be read by a maintenance crew sometime before the aircraft lands in order that they can be prepared for a repair/ box swap. They are relatively low urgency, low criticality messages; 'anomalies' could be seen for a number of reasons, such as:-
1. Source Message Generation Delay. The originating sub-systems usually check inputs from sensors, possibly via an AtoD converter, against predefined criteria (range check, rate check, comparison) and may conclude that the input is 'bad'. The corresponding output(s) to other sub-systems over the ARINC 429 would be marked as 'invalid' with a default value; if further readings over subsequent cycles are still bad, then a 'failure' maintenance message may be generated by the sub-system. i.e. the fault goes from being possibly intermittent to 'hard'. The period of time between the first 'bad' reading and the failure message being generated could be 10's of seconds. The message may be given a time stamp when the fault count was started. If the Pitot readings were suspect some time in the minute(s) before 02:10; the AP could then be the first sub-system to complain, then later (message 14) the 'hard failure' was registered and (message 18) the NAV ADR Warning was generated. This possible maintenance message delay before a fault is declared 'hard' could explain why the Failure messages (19 & 20) time stamped at 02:11 are 'after' the message at 02:12 and the one at 02:13 (message 24) is after 02:14. 2. Potential for Missing Messages It is possible that some messages were not transmitted due to a full buffer within the CMC. I would expect that the message queue handling software would have a wrap around buffer with protection to prevent the buffer 'over filling'. However, the assumption may have been made that only a few maintenance messages per flight would be the norm. The nominal transmission rate of one message every 6 seconds allows for a sustained rate of 10 messages per minute. A buffer size of 10 messages could (with lack of hindsight) seem sufficient. During 02:10 the flood of 15 (or more) messages within a minute may have caused some messages to be 'lost'. 3. Messages not exactly every 6 seconds From the SITA website (www.sita.aero/file/1569/Aircom_new_generation_services.pdf) the satellite communication uses a Carrier Sense Multiple Access (CSMA) protocol for Media Access Control (MAC). This mean that before an aircraft starts transmitting, it first checks to see if anyone else is transmitting. To avoid repeated retries if 2 aircraft happen to be in phase on a 6 second cycle, the time between transmissions for each aircraft would have a different, random 'jitter' applied to the basic 6 second cycle. 4. Messages at 15 second interval There are 3 messages (10, 13 & 16) that all have a received interval gap of 15 seconds; my assumption is that these could be messages that were not acknowledged as having been received by the ground station. Comms protocol usually require that if the transmitting station does not receive an 'ACK' from the end receiver within an appropriate time interval (3 seconds would seem to me to be not unreasonable), it will hold off transmitting the 'next' message and resend the unsuccessful message again. This would give a 9 second delay on top of the normal 6 second cycle. 5. Message 18 gap of 31 seconds Message 18 seems to be where the message buffered has just been flushed as the time stamp and received time are both in the same minute. That would suggest to me that the gap is due to no messages being generated for 5 cycles of the 6 second transmission slots 6. Loss of Signal I seem to remember reading somewhere that the INMARSAT link uses a once per minute status message (unrelated to ACARS messages) to monitor which aircraft are still in range. In which case the sat comms would know if the link was 'lost' or not. Conclusion: The flood of 15 (or more) messages, their interpretation, from diverse sub-systems and all at 02:10 could suggest that the aircraft went rapidly into a chaotic flight state, probably a bit before 02:10. In which case point of impact would be as likely S of LKP as N. |
ACARS system knowledge
Ok, but surely the investigating team is fully clued up on ACARS and would be capable of generating possible scenarios ? If the search area is still to the north seems they either came to a different conclusion or this line of analysis escaped them. The latter would be deplorable so I hope not.
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Hi,
. . . . . . . Airbus has discovered that in some cases two Pitots can give matching, incorrect speed data, which could lead pilots to re-engage autopilot prematurely . . . . Read more: CBC News - World - Airbus gives new warning on speed sensors Airbus is warning pilots about a dangerous potential malfunction of speed sensors on aircraft like the Air France A330 that crashed into the Atlantic last year, killing all 228 people aboard, including a Canadian. If it's a malfunction is to the manufacturer (or the airline) to fix it .. not the pilots ! |
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AP Reconnect
So assume the AP was reconnected with two faulty tubes reading the same, would the ACARS messages that followed be consistent or inconsistent with that???---thinking of the PRIM and SEC faults.
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The possibility of Upset prior to 2:10 is addressed in many places here on Thread.
Upset would include (potentially) bad AS and IRU's. Leading to Computer failures. Is this not correct? The Computer is NOT programmed to fly in upset, nor is the a/p. I thought we had determined all this. |
Originally Posted by thermalsniffer
(Post 6138351)
So assume the AP was reconnected with two faulty tubes reading the same....
All it would need is two pitots icing up in a closely similar manner.... and that wouldn't be the first time that has happened. And yes, the ACARS messages would have been very similar, initially. |
ACARS Messages on AP reconnect
Having worked on fault detection/management on Avionics sub-systems I find difficult to comprehend how there could be such a sudden 'burst' of ACARS messages, 15 (or more) of them, in a minute, from diverse sub-systems. Such a sudden burst suggests that some messages would have been generated by different sub-systems at the same time. There may not have been time for the pilot to reconnect the AP before all of these other warnings came up on his screens; the AP would probably have been the least of his worries!
Considering that the pitots are all in the same environment (and located in the same area!), it is quite possible that two (or all 3) pitots iced up in a similar fashion. However, I would not expect them to ice-up in synch. Instead, I would expect that one pitot would provide 'bad' data before the other and the degradation (warnings from other sub-systems) to be a more gradual process. As a comparison, the data derived from QF72 FDR (Table 3 in www.atsb.gov.au/publications/investigation_reports/2008/aair/ao-2008-070.aspx) shows:- 1. The first event at 04:40:28 as AP1 disconnect 2. Some other warnings that perhaps resulted in a few (a lot less than 15, I would think) ACARS messages over the next minute. 3. Another minute before the first pitch down event occurred 4. Nearly another 3 minutes (04:45:11) before Flight Control went to Alternate Law This is in a situation where 9 parameters from ADIRU 1 were recorded in the FDR as having “spikes”, with one (AoA) having a recorded 42 “spikes”, with probably other spikes not recorded. In comparison on AF447, only a single sensor/parameter is seen as being the prime suspect in supplying 'bad' data, but the Flight Control Alternate Law Warning was just two messages later, probably occurring somewhere between 0 and 12 seconds after the first event (also AP disconnect). Is it really possible that pitot icing could have caused such 'instant chaos'? |
VicMel
I think it is unlikely a pitot tube caused the avalanche of ACARS, as you also propose. Of more interest to me is the operation of the a/c prior to the AP disconnect that occurred within the parameters of control limits the AP was programmed with. These limits are not narrow, the Pitch allowables are I believe 24 degrees (15 U and 9 D). The Roll limits are 45 degrees per side, for a total excursion of 90 degrees. Is it possible that the crew were satisfied with a rough ride that took the a/c to its limits of "comfort"? We hear from time to time of the explicit Faith put into this a/c by its pilots, and a desire to fly to the AP disconnect as a conscious decision is certainly plausible. If at this time, Law regression and bunk weather forced an immediate decision on the part of this crew to NOT re-engage AP, upset may have already occurred, and as has been explained so many times, conditions of flight were marginal perhaps in ALL respects, and control may not have been recaptured. To me, it is difficult to imagine an orderly march of messages in transmitted messages of ACARS, the sheer number alone suggests that the system had been totally overwhelmed v/v sequencing prior to AP drop. If upset had occurred in this way, the failure of three pitots virtually simultaneously suggests an Unusual attitude or two were involved in the bunk AS reads. imo. bear |
VicMel,
I'm afraid you're barking up the wrong tree... Events with two out of three pitots icing up synchronously, with the A/P "believing" the wrong data, and similar strings of fault messages, have already happened. They didn't lead to a crash, because the pilots understood the problem in time, and used "pitch and power" to "fly out of it"... which is why we have the full sequence of fault messages from the FDR, rather than a fragmentary sequence of ACARS messages. The very recent Airbus memo about not re-engaging the A/P too soon after a "loss of speed data" event also clearly points to their thoughts about the subject.... bearing in mind that they may not know a lot more about what actually happened to AF447, but that they know a lot more than we do about how the systems and aircraft would behave in similar circumstances. |
ICAO High Level Safety Conference (2010)
Following the ICAO 2010 High Level Safety Conference, the Interstate Aviation Committee (IAC/MAK) comprising many of the independent republics of the former Soviet Union, has presented a brief report on their assessment of real-time data transmission by aircraft over oceanic FIRs, in low density traffic regions and outside inhabited areas.
The ICAO Flight Recorder Working Group is already engaged in assessing the viability of alternative means of recovering flight data, and the ICAO has accepted the IAC/MAK paper as part of this investigation. The paper, which has been translated by the IAC/MAK into English can be viewed at:- IAC Flight Data Paper References within the paper are made to the AF447 situation, and it would seem probable that the recent reference by Le Figaro to the Russian Army being involved in discussions with the BEA, could more correctly be described as Interstate Aviation Committee instigated. |
Has any date for the resumption of search activity been announced?
If I missed it, sorry. |
wes_wall;
The Phase 4 search is expected to get underway in mid to late February 2011. |
well, this might be a little unconventional but:
has anyone tried to use some parapsychologist technology to show possible location of the plane? use several well qualified and independently working people to get several locations spotted, select where the density of spots is higghest and check there. This is a known and used way of founding things on the ground and AFAIK it works as well over water but it may have to be assisted by better maps of the bottom surface? there are people capable of doing such things - with good results, even it there is much more people who do not believe this. I do not want to start a - i believe - i do not believe - discussion here. Just pointing out a possible way that can be exercised even before start of the coming search phase 4. |
WojtekSz,
I don't think psychics would really help... |
After all, why not?
When we look behind the sofa of official researches, it seems justifiable to wonder what is the game of officials who make those researches. And here are questioning of a 447's victims families association (I'm sorry, go²gle translation). |
why not go all the way and ...
why no go all the way then and ask the parapsychologists to give us the answer, Why AF447 went down ...
:rolleyes: (Sorry, couldn't resist ...) |
Hi,
Maybe the investigators have already used the parapsychologists. And if they did .. they do not say ... for fear of appearing ridiculous |
Yiorgos:
why not go all the way and ... Imagine observing a medical operation that goes wrong: could you recognize what went wrong even if looking at all available displays or listening to short words spoken between the operating crew? Might be difficult... Imagine yourself being able to see with your own eyes (even only as a vision) what was happening inside the cabin during the long minutes when the plane was falling down and when it started to sink. Could you mind stand up to the memories of witnessing sounds and pictures of people starting to understand tey are doomed? Memory of this would stay with you forever, every night and day. jcjeant: if you would have to decide where to search, knowing that last three attempts were looking at quite different areas after receiving very different scientifically based opinions, and that each day costs a lot of $$$ than alternative solutions does not look that much extravagant. Just think how many people use similar technology when digging for water. |
"It's tough to make predictions, especially about the future."
Yogi Berra The problem with obtaining information through interpreting tea leaves, divining sheep entrails, throwing darts, astrology and other paranormal means is that they are pseudoscience. It has nothing to do with having open mind. There is simply no basis in fact for employing these techniques because they are not effective. The excellent magazine "Skeptical Inquirer" (The Committee for Skeptical Inquiry) has many interesting articles about these and other techniques available on-line. |
I have been channeling Wiley Post. He says...........
"Why not search the area that has not been searched??" mystic bear of the Four Roses |
Bear, Wylie Post may have sounded quite cogent in this regard to most. To me it's rubbish. And I'll stake my reputation as being the person in this household to go to for finding things.
I do not always find them first pass or even second or third. I just don't give up. Eventually something will prompt me that "I've not looked here before" and I find what I am looking for. That is if I don't discover it in a place I looked at and simply didn't connect what I saw with what I was looking for. And this is after my partner has looked for an hour or so. If you're looking for something, and you have reason to believe it is within a specific volume, then don't stop looking. Expanding the boundaries is usually good for a break. But most of the time the prize is within the original search volume. Of course, it helps to search the entire likely volume, repeatedly, before branching out very far. The key is, "Don't give up until the prize is in your hands." Giving up guarantees you will never find the prize. |
JD-EE,
As my wife has pointed out to me the past and I daresay will point out to me many times in the future, "Did you have a MAN look?" You are right, many a time we males do not see things on the first pass or at all!!:uhoh::uhoh::uhoh: |
You are right, many a time we males do not see things on the first pass or at all!! 'Man' searches are rarely 50% succesful n this household :ugh: Unless searching for something a female has lost or mislaid which ups the % a bit :) |
Boys just give up to easy. And if it was a simple testosterone thing you'd think men would obsess about it until they found it. So it must be something else. Cultural?
Anyway, the key is persistence - if the famn dool thing still exists. |
JD-EE et al
I usually find things in "the last place I look", then again if one keeps on trying other places after finding something it raises questions about mental status.:O As to women being better at finding things; True enough if the objects are in plain sight or where they belong, on the other hand maybe not so much if a true sieve approach is required. I once found a girlfriends lost pay check which she hid while drunk because she was afraid of theft or that she would misplace it. (I did mention she was drunk...) Starting at one end of her room I individually examined each and every item larger than a coin. (she could have folded it to fit it somewhere.) When I began inspecting each tissue in a box of Kleenex she was making great fun of me untill I found the paycheck about 1/2 way through the box. Even so I almost missed it because of the way the tissues were interleaved - it was a good hidding place indeed. Guess the point is that in the current context it is impossible to say that the recorders are not somehwere that has already been searched since the "sieve" approach cannot be used. |
Does anyone know if the Searchers are proposing to introduce additional audio/visual (evolutionary) equipment to the equipment they have used previously?
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Hi all,
apologies if this has already been covered or if it is completely irrelevant but I saw this thread and it reminded me of something someone mentioned and I keep meaning to find out more about it. I am currently doing a type rating with my first airline so don't know much about this area but during a CRM course the instructor was talking about the Operational Flight Data Monitoring system and how it instantaneously alerts a land based computer system when an aircraft exceeds its limitations, such as flap exceedance speeds. He briefly mentioned AF 447 afterwards but I only caught the last few words. To cut to the chase, is it true/possible that Air France will have an idea of the situation of the aircraft immediately prior to its crash as a result of the OFDM system highlighting the parameters that were exceeded? If so with the data the OFDM provides (I'm not sure what information this is) do you think Air France have a pretty good inclination into the cause of the crash? The only things I caught when he mentioned AF 447 was that the information Air France had from OFDM would never be released to the public. Thanks |
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