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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 21st May 2011, 01:37
  #1981 (permalink)  
 
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That they responded to the Press at all is incompetent. To make moral judgments re: people's feelings, freedom of opinion, and what is proper in the culture is inexcusable. Their credibility is damaged greatly, jcjeant is on the money here.

As In: Pushed to respond to a mere gnat, (The Press), imagine how anxious they will be whilst composing their Final.
Give me a break!

They will be far less anxious composing their final report than you and jcjeant will be in awaiting its content...
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Old 21st May 2011, 02:31
  #1982 (permalink)  
 
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Originally Posted by Turbine D
They will be far less anxious composing their final report than you and jcjeant will be in awaiting its content...
I'd venture to guess that whatever they say, our anti-Airbus cabal on here will consider it a stitch-up in any case. Still quixotically tilting at 23-year-old windmills...
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Old 21st May 2011, 02:43
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Pilots must be proactive; The System is reactive

John,

which is why we try to stay away from situations which might involve an extreme event.
After learning on 38 UAS cases since 2003 we may ask: Are the the present airworthiness system working pro actively (in important issues like this one) like pilots naturally do?

Now, whether this mishap is the result of aircraft deficiencies, crew deficiencies, operational deficiencies, Design Standards deficiencies and so forth .. will come out of the investigation. Aspects of design and procedures may well be varied to plug whatever holes are found to exist in the dyke .. time will tell.
IMHO on this subject there is a "slow moving bureaucracy" affected also by lack of will to invest (and be proactive).

Since the Comet investigation the System still moves only after the losses.

And the UAS cases of a parameter so important indeed strongly recommends to pilots to act pro actively "staying away" like you mentioned.

My point is: Considering the System lags behind (bureaucratically) pilots increasingly operating complex a/c systems must realize the (natural?) limitations of the System.

I worked in a (private) positions report network in the seventies (using TTY, HF rig, etc. ) and after reading the comm. logs of AF447 and analyzing reactions of brazilian, senegalese centers i ask: What was done (or is being made) to fix the errors that occurred at that night? This relates directly to safety and that´s the reason of my question.

Mac

Last edited by RR_NDB; 21st May 2011 at 15:56.
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Old 21st May 2011, 03:22
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02:11:55 EFCS1 X2,EFCS2X,,,,,,,FCPC2 (2CE2) / WRG:ADIRU1 BUS ADR1-2 TO FCPC2, HARD
This is definitely a wiring fault, where FCPC2 and ADR1 lose their connection


I thought that it had just been reported that the BEA had said that they had found no faults with the aircraft after examining the FDR. Or would this 'wiring fault' not be apparent at this time?
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Old 21st May 2011, 03:29
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Originally Posted by gums
My problem with the Airbus fly-by-wire implementation is two-fold: 1) Too damned many reversion sequences and autopilot connections with the flight control computers with their laws and sub-laws and sub-sub-laws....., then 2) Flying with aft c.g. that most planes would not be certified for.
As I've said before, the thing is that comparing FBW as it is applied to a fighter jet like the F-16 (constant correction due to inherent instability in the airframe) with how it is applied in an airliner like the FBW Airbus series or the B777 (to assist pilots in managing the flight on a stable airframe) is to ignore a fundamental difference in the design specification - i.e. a completely different set of problems.

The F-16 had to handle modes of operation that would be completely outside the frame of reference required by an airliner, and on top of that it was a pioneer in it's field - so it's hardly surprising that it was possible to "throw" the computer. While the A320 was the first fully-FBW airliner (aside from the H/S mechanical reversion you mention), it drew upon experience from the development of the A300 series - and before that - Concorde (which was effectively analog FBW - if you haven't checked out the Tech Log Concorde thread, I urge you to do so - it makes for fascinating reading).

The A320 series FBW control law reversion looks complicated on paper, but I can assure you that it was designed to behave in a completely logical manner in flight, and the design pattern it followed had input from line pilots as well as engineers - something that rarely gets mentioned. The FMC (autopilot) and FBW technologies are not that closely intertwined and can effectively be thought of as completely separate systems. The design of the automation as a whole was completely optimised for airliner operation, which is why looking at it from the perspective of FBW as implemented in fighters it's not likely to make much sense.

The analogy I like to think of is that you wouldn't try to plough snow with a combine harvester, despite the fact that the underpinnings of a snowplough and combine harvester are very similar.
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Old 21st May 2011, 04:51
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gums The YF-16 could be flown with a "conventional" forward c.g., but allowing it to move aft provided a dramatic increase in several parameters
how much is the range of moving aft the CG for the YF-16 ? 40%?? 45%? or more ?

my raw calculation for an A330 with 205t is that the change of CG is abaut 0.7m if you transfere 4,8t from trimtank ca. 31m(?) foreward to centertank (31*4,8/205=0,7)
100% of the profile may be around 6,6m ,and if the trimtank was full (?)
the max cange in CG is 10,6% (0,7*100/6,6=10,6)
given CG 37% the max forward CG in that case might reach 26,4%


p.s. if 10 Pax move 40m the change of CG is not nothing, it is ca. 2,2%,
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Old 21st May 2011, 07:02
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SEA SEARCH OPERATIONS - Summary

As previously mentioned by noske, the BEA has recently published (in French) a summary of the Sea Search Operations. The conclusions reached have been translated into English below:-
The discovery of the wreck concludes months of searching in very difficult conditions, from which can be drawn the following conclusions:
  • aircraft position reports must be more frequent (AF 447 reported its position every 10 min). This is precisely the subject of a recommendation made by the BEA in its interim report dated 17 December 2009;
  • drifting buoys should be dropped as soon as possible after the accident in order to track the drift currents, which beyond a few days can be largely unpredictable;
  • the Underwater Locator Beacon (ULB) frequency of 37.5 kHz is not suitable;
  • the transmission time of acoustic beacons (ULBs) should be increased from 30 to 90 days: it is still not certain that they actually worked. The recommendation made by the BEA to install an additional beacon emitting a lower frequency and potentially having a greater range, will reduce the risk of non-detection;
  • the Remus AUVs, equipped with sonar and cameras have proved a very effective resource;
  • the exploration of a very deep rugged seabed, far from the coast, is a technological and organizational challenge. Mounting such an operation which makes use of globally rare material resources and experts, requires large financial resources (about 5 to 15 M €) and involves significant delays.
They have also confirmed their confidence in the Remus Autonomous Underwater Vehicles (AUVs) operated by the Woods Hole Oceanographic Institution for this kind of operation.

Last edited by mm43; 24th May 2011 at 19:58. Reason: correction - uncertainity about ULBs working
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Old 21st May 2011, 07:34
  #1988 (permalink)  
 
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jcjeant, speaking in USA terms BEA has an absolute right to criticize Le Figaro for its sloppy reporting and request that they shut the (whatever) up. And Le Figaro has an absolute right to go on being rectal orifices.

In French terms I am not sure what rights, if any, a person has. But if BEA does not have a right to lay into Le Figaro for irresponsible reporting something is, IMAO, terribly terribly broken.

Had BEA not lit into Le Figaro that way then Le Figaro's sensationalism would stand and gradually become perceived as "truth" when it may not have been.

edit: Let me add that nothing BEA did constitutes censorship, the action of preventing someone from publishing as they choose. Nor is anything BEA did in the least bit immoral in an honest world. They did NOT extend a hand to prevent Le Figaro publishing. They simply declared Le Figaro and its reporter were reprehensible people.
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Old 21st May 2011, 07:53
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jcjeant, I suppose it is morally correct to slam the victims families back and forth trying to deflect their suit with a purely preliminary observation on the data. Suppose that given what Le Figaro has published that appears to have you absolutely convinced of the Pilot's and Air France's fault we still find it was an AirBus error. What did this do to the families? They thought there was a conclusion and they can get on with suing somebody into bankruptcy or whatever else they want to do. Then their plans are upended and their emotions are strung out again.

You're starting to reach too far, make presumptions of guilt with which I am VERY uncomfortable. Is this the German way? In the US you'd be utterly unfit for jury duty if you jump to conclusions with this level of facility.
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Old 21st May 2011, 08:18
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RR_NDB, what would "hi-fi" bring to the table other than a lot of noise that would have to be filtered away to hear the voice clearly? Surely as a ham radio operator you have played with filters to make understanding what is being said easier. Have you ever found that a 15 kHz wide filter could make a voice in noise sound clearer? Have telephones ever seen a need to go to 15 kHz audio response for general use?

Memory is cheap, today. But, the plane was designed when large amounts of memory were quite expensive and quite large. So having the electronics filter the sound the way it was is likely necessary.

With today's model recorders will likely store more - days worth? - rather than more bandwidth unless the bandwidth really buys "something" if applied to all the microphones. (However, I might store more channels to get information about wind flow around the cockpit and record them with 96ksps at 16 bits in the hope that might provide information that could diagnose cockpit noises as ice on the windshield, flying through rain, flying into a sudden up or down draft, etc.)
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Old 21st May 2011, 09:21
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JD-EE
In French terms I am not sure what rights, if any, a person has. But if BEA does not have a right to lay into Le Figaro for irresponsible reporting something is, IMAO, terribly terribly broken.
IMHO, the BEA didn't exactly told Le Figaro to "shut the (whatever) up" ; their phrasing was very carefully chosen : "The BEA [...] alone has the right to communicate on the progress of the investigation. [...] any information [...] from another source is null [...]" (check the BEA site for the full sentence) : translation : "neither Airbus nor Air France nor anybody else in the industry is supposed to communicate on this subject". Thus they don't order Le Figaro to stop publishing, they just question the reliability of Le Figaro's source, according to the fact there has been no official info from BEA.

At the end of the day, the net effect is the same : BEA 1 - Le Figaro 0.

Last edited by JPI33600; 21st May 2011 at 09:25. Reason: precisions on who can communicate on the investigation
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Old 21st May 2011, 09:27
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A few observations:
1. I accept that this FBY technology overall is a good thing, and understand that some of you are saying it is pretty much essential (to a greater or lesser extent) for aircraft of this size.
2. I have been surprised at how often you to disagree about the detail - much more than I would have expected. There have been vigorous debates about the principles of various flight laws, or the implications of a particular error message. Maybe this is because you do not all operate the A330, and that some of this detail is particular to that aircraft type. Or would there still be disagreement among a group of A330 pilots?
3. A lot of this stuff seems based on IT rather than "airmanship", and I wonder if this is a problem. When things go wrong in an aircraft, there will sometimes not be sufficient time to work through what is going on and what it means. The situation will often deteriorate while you are thinking. This is true in many areas of life - there is not a pause button where you can freeze the situation and work out what is happening and what to do. Sometimes you have to act - because not acting will lead to a disaster.
4. IT is often a bit different - stop, understand, then act. But many areas of life require prompt action. I am 100% sure the IT people that produce this technology understand this. But I do wonder if there is not some remnant of this thinking in the way this technology is developed. Is there a small residual bias that assumes there will be time for the pilot to work through the problem and take the correct action. Rather than overloading the pilot with information, should this technology simply allow him/her to get on and fly the plane, and encourage him/her to do so? I remember seeing the interview with the Qantas A380 pilot after that engine failure out of Singapore - page after page of error messages to work through. How would this have turned out if the consequences of the explosion presented a more immediate threat to the aircraft?
5. I was interested in the view expressed by someone here a day ago that this technology can disconnect a pilot from the aircraft to the point that s/he is unaware of a deteriorating situation - of how close the system can be to failure, and how the pilot could be totally unprepared to have control thrown back to them. This issue makes sense to me.
6. I wonder if this is a wider problem in society. Overall we are making things more reliable and more user friendly and more accessible. We are doing this by dumbing down technology, and taking the view that end-users "don't need to understand it". This means that a smaller % of users understand how it works. Overall I guess this is a good thing. Except when it goes wrong of course.

My 2c on philosophy today.
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Old 21st May 2011, 09:33
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Lonewolf 50, Continuing on the "gyro re-alignment" subtopic:

I'd guess that a checklist or something like an ECAMS resource in the cockpit would walk the pilots through the step by step if such a realighment/recaging were necessary inflight.

Perhaps not, perhaps fixed only on the ground.
As far as I understand, such manual operations should not be necessary.

I did some googling and found out about this Northrop Grumman LTN-101/101E GNADIRU (Global Navigation Air Data Inertial Reference Unit) which is certified for Airbus [correction: but was not installed on AF447 which had Honeywell units, see next post below].

As the description says, it integrates air data, inertial (solid state gyro based) and GPS data and continuously "realigns" or calibrates itself to maintain data integrity using something the manufacturer calls AIME (Autonomous Integrity Monitored Extrapolation) technology. "AIME continuously analyzes available satellite and inertial signals. If the data’s integrity is compromised, AIME automatically uses the aircraft's position history to maintain accuracy and integrity. Onboard predictive Receiver Autonomous Integrity Monitoring (RAIM) programs are not required".

This is probably a similar (but enhanced) concept to that used in many car navigation systems, which use GPS for primary positioning but revert to inertial sensors (solid state MEMS) when GPS signal is lost in a tunnel.

An interesting "side feature" of such an integrated system is that you could use it "in reverse" to calculate e.g. the strength and direction of the wind gusts that hit the airplane, by comparing the differences between air data, inertial and GPS data. It will be interesting to see if this kind of results will appear in BEA's report, given the turbulent weather conditions that we know were in the vicinity of AF447.

Last edited by snowfalcon2; 21st May 2011 at 10:45. Reason: correction, thanks for info
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Old 21st May 2011, 09:51
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snowfalcon2,
The accident aircraft was equipped with Honeywell ADIRUs, though it is certainly possible that they are also equipped with a similar function.
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Old 21st May 2011, 11:24
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Figaro si, Figaro là

DenisG said


With regard to your posting above concerning the pressure that is being piled up from " ...political and economic power...", let's please not forget that everybody in this forum who is participating in the discussion about AF447's accident cause, including me, is contributing to this pressure as well, which is in many perspectives a very positive development, compared to e.g. 15 years ago.
I understand what you are saying but I disagree on some aspects. Even if the Internet medium is today a major tool in communication and propagation of opinions and ideas, I do not think that a State Agency such as AAIB,BEA,NTSB etc...in charge of an aviation disaster would have time to watch various forum, including the best of them and to act according to what they read. No, imho pressure are really coming from political an economical powers. In my country like in many others, political and economical worlds are so tightly linked that you can barely make a difference and determine who exactly gives orders to the other.
Two days ago, as I relayed here (I'm not a journalist btw, just working in the Aviation industry and consider myself as a SLF) Mr Mariani (junior minister of Transport) said publicly that a report would be doubtless published "late June". Very well, let's wait. Normally a statement from a minister should not be contradict two days after. Yesterday we learned that the BEA will made a major update in one week. The BEA being a State agency they are obviously under pressure of their management that is to say the ministry. And they certainly won't do that unless authorized by their management. Even a representative of a victims association wonders if the things are not going too fast now . We are walking on the head, with a situation where (almost) the same peoples, who, some months ago were asking for more transparency, efficiency and speediness, are now begging for less precipitation to guarantee a reliable result for the manifestation of truth. But PHG spoke very opportunely and at the same time we learn that AFR-KLM, who needs to renew its long haul fleet will postpone its choice until this Summer.

JPI33600 said

IMHO, the BEA didn't exactly told Le Figaro to "shut the (whatever) up" ; their phrasing was very carefully chosen : "The BEA [...] alone has the right to communicate on the progress of the investigation. [...] any information [...] from another source is null [...]" (check the BEA site for the full sentence) : translation : "neither Airbus nor Air France nor anybody else in the industry is supposed to communicate on this subject". Thus they don't order Le Figaro to stop publishing, they just question the reliability of Le Figaro's source, according to the fact there has been no official info from BEA.
Exactly, but like in other democratic societies with a free press, journalists publish informations that they consider reliable. In France, the sources of the journalists are kept secret. Periodically this debate about the sources secrecy is coming on the public scene because of sensible informations published in such domains as politic or Justice. The political power, sometimes, is really annoyed with that.
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Old 21st May 2011, 11:29
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mm43,
The point they made regarding "uncertainties about how the ULB's work" is a little puzzling. I suspect they are really referring to the "unknown" effect that salinity/temperature inversion layers may have on the path of the acoustic signal
Was not the BEA just meaning it is not yet determined whether the ULBs did transmit or both failed ?
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Old 21st May 2011, 13:24
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Cool

Hi,

The opinion of HMC

AF 447. The "circumstances" of the accident: an "unsafe condition"

Thus, BEA announced it will unveil the "circumstances" of the accident on 1 June 2009 next weekend. In reality, the BEA will say * "how the accident took place after reading the recorders. She will then determine "why" this tragedy happened.

Because the "circumstances", that is to say the situation was the A 330, its crew and passengers, were known by the Flight 447 was going through a very disturbed area (whose characteristics have been widely underestimated in the weather records provided to the crew during the flight preparation), it was dark, the pilot avoided the active nuclei, the workload was so important. She suddenly became excessive because, following the blocking of pitot probes, the crew had to perform 13 procedures in a very limited period of time (among them, the procedure was ineffective and unreliable AIRSPEED acknowledged that Airbus)

The "circumstances" of the accident are therefore excessive workload in a degraded environment no longer allows the crew to perform its tasks with precision or their completion.

That is what is called a "unsafe condition".

The risk of this "unsafe condition" related to the inconsistency of the output was measured velocities of the flight, that is to say the aircraft's stall. The FAA had said in 2001 and reconfirmed after the accident when the probes were removed by Thales emergency.

Nobody has taken into account.

Finally, we recall again here that blocking the pitot probes by ice crystals is a design flaw due to certification standards obsolete. This is not a failure. If the drivers have a responsibility to deal with failures listed by the application of procedures, it is the responsibility of the manufacturer and regulator to eliminate all defects from an airplane. Equipment of an aircraft must operate throughout its flight envelope (ref. CS25)
Source:
AF 447. Les « circonstances » de l

Last edited by jcjeant; 21st May 2011 at 13:44.
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Old 21st May 2011, 13:40
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Cool

Hi,

JD-EE

They thought there was a conclusion and they can get on with suing somebody into bankruptcy or whatever else they want to do
The families organizations work with assistance of barristers and solicitors and aviation experts .. so be sure they will sue who is to be sued .. and in due time !
The newspapers don't play any role regard the decisions taken by families organizations.
Reminder:
Air France and Airbus are already sued (Justice court of Paris)
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Old 21st May 2011, 13:46
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Originally Posted by slats11
A few observations:
You are making some valid points here but it should be nuanced: all people around don't know what the real situation faced by AF 447 was. Those interpretations are not based on DFDR or CVR data but on those ACARS reported which are following their own logic (Central Maintenance Computer), a logic quite different from any live report. Those ACARS have a different content, timming, meaning and purpose than real time cockpit warnings; moreover, they do not provide any clue about this crew action/reaction and they are far from complete in this form (a short header lacking the full data to be downloaded from CMC); also, everything happening in the cockpit is not covered by ACARS and some of these ACARS do not show on cockpit screens.

IT stuff vs. Pilot stuff: you can't train the crew to fully master every bits of avionics or the whole troubleshooting process. Hence, assisted procedures are to be developped in order to help them for recovering what system they first need in priority for the next phase of the flight (procedures being flight phase related). Faults are hierarchised by order of priority, but it is quite challenging when many warnings of the same priority level are triggered almost simultaneously (AF 447).

This is where ergonomy/interface (and training with it) plays its critical part as too many warnings may also induce too much stress/work for the pilots to understand quickly what is going on. Especially if, beforehand, their situation awareness was very low while the process was designed for the pilots being entirely dedicated to their task. Same isssue if the event is particularly improbable and/or complexe (like A380 case). Consequently, the workload resulting may be critically affected by external factors than those taken into account during each procedure implementation. On the other hand, it doesn't mean that the procedure is always soundly elaborated as it may also appear that it is flawed in combination with other ones triggered at the same time. In this case, time and feedback from experience is the only way to correct such issues, because neither the Pilots nor IT could ever agree to make it perfect from the drawing board stage.
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Old 21st May 2011, 14:11
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Quote from this post
Originally Posted by NandoCarioca
I shall say to TAKATA em SATURNV that all information, regardless of its nature, should be posted and thoroughly discussed. So please guys, keep questioning, but most important and most of all, keep answering.Along this past 5 weeks I learned a great deal of technical information, in several fields of expertise, which I never suspected existed.
That's why the public should have access to the data as well.
Of course the BEA would still keep the lead in the investigation.
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