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-   -   AF 447 Search to resume (part2) (https://www.pprune.org/tech-log/449639-af-447-search-resume-part2.html)

lomapaseo 21st May 2011 15:43


If they want reply to press articles they must be factual and not emotional.
They have to publish a strong denial or a strong approval.
Nuts!!

How in hell do you expect them to do that when the facts are not yet in evidence.

At least in a technical forum we get to debate speculations with some degree of balance. and we sure as hell don't yet agree with the news article.

When a newspaper prints statements as this,without being vetted by broad experts, it can cause great harm.

the BEA was correct in their response

john_tullamarine 21st May 2011 15:50

One of the considerations is that the typical FDR output really is not suited for publication as is. Generally it needs a bit of tidying up to end up with something which makes reasonable sense.

I guess the short term problem is the usual one resulting from social acculturation by media to desire a quick ten second news bite .. rather than the traditional boring, tedious, do all the work, engineering analysis in between input and output.

bearfoil 21st May 2011 15:54

"...When a newspaper prints statements as this,without being vetted by broad experts, it can cause great harm..."

Yes, that is a given. It is also the baggage that comes with a free society. A large net catches many different fish.

The argument, I submit, is where is the line drawn in disclosure of information, 'data'? It is not about Trust, but Choice. Who makes important decisions for us? Hopefully, we do. We also put Trust in agencies and bureaus whose mission it is to represent the People. The Client of these constructs is the People.

To the extent that publicly supported agencies engage in spin or favor to individuals (Corporations included), this mission is subverted. In any large group, there are miscreants and those whose mission is other than the common good, it is legend.

Data, belongs to all the people, any resistance to disclose can and should be met with great suspicion. It is a fundmental principle.

John- The Press is a pain in the ...elbow. But it is our elbow. I don't disagree with the timing at all, there are different needs for different disciplines. Ultimately, everything should be on the table, "tidying up" should be open to critique, yes?

ChristiaanJ 21st May 2011 16:39


Originally Posted by bearfoil
Ultimately, everything should be on the table, "tidying up" should be open to critique, yes?

I have the impression you've never seen or had to work with raw flight test data or FDR data....
They are just long meaningless tables of initially meaningless numbers.
(Read the earlier posts (a few pages back) about coding and scaling and calibration and time-stamps.)

"Tidying up" is a misleading term.

All those numbers are first "decoded" and "translated" into "real" values, such as speed, altitude, control surface position, etc., then plotted. and checked and correlated for verisimilitude.
The "tidying up" then consists in extracting the "story", and finally in producing a legible report, usually with info-graphics that are understandable by the public, and non-specialists.

takata 21st May 2011 16:52


Originally Posted by CONF Iture

Originally Posted by Takata
a PRIM reset is also mandatory before doing it

No, it is not.

You are right and I stand corrected on that point. I based that on the fact that many crew reseted their PRIM after ADR disagree events, but the procedure is mentioning clearly that Alternate can't be cleared until after landing.

On the other hand, RTL (Rudder Travel Limiter) rule out the reversion to alternate in AF 447 case. The fact that the rudder settings were still frozen after impact imply no reversion from ALT2 because it would also have cleared the RTL fault (having now two "good" ADRs back, even if both "wrong").

Consequently, IMO, it means that ADR DISAGREE situation was also not cleared until impact: they would never have had the opportunity to re-connect either autopilot or autothrust after 0210, while no other flight envelope protection other than "g load" would have been active before crash time. In this context, the possibility for a supposed induced "aircraft system upset" happening after 0210 is more than very thin. Don't you think?

KBPsen 21st May 2011 17:04

To give technical explanations or reasons why is energy wasted. From the very beginning the course chosen by some have been to cast doubt on everything and anything, to suffer from a selective memory and other pretenses. Not due to cause but for own purpose.

Less of a principle, more of a condition.

bearfoil 21st May 2011 17:09

[/B]Hi. I wouldn't know what in the world to do with raw data. I would need help understanding the final product. That is not to say I think you or CONFiture should be excluded from making the attempt. I think in this is a minor misunderstanding. Any agency acting in the Public behalf must be subject to scrutiny from whoever has the desire to. Here is the rub. The Public is complacent, and in technical things, generally also ignorant. On top of this add a poor memory, and the Field belongs to the sly, or the greedy.

Here, a distinction. BEA is not likely the source of any potential problem. It is the unseen players whose power and influence are acceded to, to the detriment of Public safety. I am disappointed BEA played into the clumsy tactics of the Figaro. Choice before Trust, and Trust is subject to change.

RR_NDB 21st May 2011 17:12

Cockpit sound analysis and not just voice recording
 
JD-EE,


provide information that could diagnose cockpit noises as ice on the windshield, flying through rain, flying into a sudden up or down draft, [etc.
As you know CVR are useful not just for voice.

We as Engineers MUST optimize our Designs and in this issue you can provide better info for the investigators just improving at a VERY LOW COST the recorder.

This is related to Engineering and not to radio operation. And could be discussed in engineering details in another thread being planned.

Bottom line:

There is room for (low cost) improvement in existing CVR´s.

bearfoil 21st May 2011 17:14

KBPsen

"...From the very beginning the course chosen by some have been to cast doubt on everything and anything, to suffer from a selective memory and other pretenses. Not due to cause but for own purpose...."

Precisely.

HazelNuts39 21st May 2011 17:18

takata;

Regarding the F/CTL RUD TRV LIM FAULT message, BEA Report #1 states:

This message indicates the unavailability of the rudder deflection limitation calculation function. The limitation value remains frozen at the current value at the time of the failure (until the slats extension command is given).

bearfoil 21st May 2011 17:27

takata

Did the RTL go fault due to lack of reliable IAS? Does the Rudder become functionally unavailable at lower speeds, then? Would that have any effect on recovery from roll, or Yaw in upset??

The Rudder was limited to 7.9 degrees sweep all the way to the Ocean, per BEA report. Is that a mechanical condition that may need to be addressed post 447?

At some point in the descent, would you have selected slats to release the Rudder? At what airspeed would the slats have been susceptible to separation?
Would slats have hindered recovery?

If too fast, and Rudder was needed, would you have selected spoilers?

Rhetorically, would Protections have limited any of the other controls?

RR_NDB 21st May 2011 17:31

Global picture of the crisis phase (>02Z til impact)
 
John,


One of the considerations is that the typical FDR output really is not suited for publication as is.
The "circonstances" report could be "enriched" by FDR data fed to SIM. For sure will not happen. The time now is for PR content.

BEA/Airbus SAS and investigation team had opportunity to "see the global picture" very soon.

And also about important facts (and decisions) before 02Z.

takata 21st May 2011 17:37


Originally Posted by bearfoil
Did the RTL go fault due to lack of reliable IAS? Does the Rudder become functionally unavailable at lower speeds, then? Would that have any effect on recovery from roll, or Yaw in upset??
The Rudder was limited to 7.9 degrees sweep all the way to the Ocean, per BEA report. Is that a mechanical condition that may need to be addressed post 447?
At some point in the descent, would you have selected slats to release the Rudder?
Rhetorically, would Protections have limited any of the other controls?

You are answering your own question.
If slats are used, full rudder deflection become available (that's the way to go out of the limitation, on purpose, if it becomes inapropriate). In AF 447 case, everything points at an aircraft staying in a clean configuration until impact.
Do not ask me why as I don't know.

wozzo 21st May 2011 17:39

Bearfoil,

you are talking about two different things here.

One, and I completely agree here, is to make raw (and processed) data available to the public. I'm all for it (as long as there are no national security, trade secrets or other plausible reasons for non-disclosure involved) - it's good policy, it can be easily done in the internet age and it may help to shut up some of the constant harping about "bias", "pressure" etc.

Two, independently of the point above, BEA is still the authority with the sole mandate of investigating the accident and determining the causes. Not Airbus, Air France, the leaker or Le Figaro. That's the point they were making with the press release (along that causes have not been determined so far), and I think it may have been necessary (alas, probably unsuccessful) to stem the tide of daily leaks.

bearfoil 21st May 2011 17:46

takata

I think we may be jumping to a conclusion or two. I don't see conclusive evidence that she "stayed clean all the way down." The BEA say she was intact at impact, fine. Intact does not mean clean at impact, neither does it mean she was not using control surfaces on her way down. BEA have said Flaps were stowed, fine. Stoweds flaps likely means retained spoilers, but does not preclude their deployment. All of the surface recovered pieces have yet to be conclusively demonstrated to have been on the a/c at impact. Please don't extrapolate from that, it is merely a statement of fact.

Still, "Clean at impact"? "Clean all the way down"? If speed is a problem, dirty is good?

wozzo

BEA is not the only authority responsible for conclusions. If the data is disclosed, "duty" can be assumed by any independent. You are confusing duty with ownership. The findings, though ennabled by BEA, are not the property of BEA. Likewise, "proprietary" or "Patent" considerations are secondary to Public good, would you not agree? National security perhaps, but what about Public carriage has to do with espionage?

ChristiaanJ 21st May 2011 17:55


Originally Posted by RR_NDB (Post 6464886)
John,

One of the considerations is that the typical FDR output really is not suited for publication as is.

I just mentioned the same thing.... been there, done that.

The "circonstances" report could be "enriched" by FDR data fed to SIM. For sure will not happen.
That is a fairly normal procedure, so why "will it not happen"?"

The time now is for PR content.
That's a separate issue. I can read FDR traces, the general public can't, and I think a lot of pilots can't either, or at least not draw conclusions from them.
Doing a 'PR job' means translating a lot of highly technical information into a statement (I will refrain from calling it a sound-bite).
I respect the BEA for not being suckered into premature and incomplete statements, other than refuting the Figaro crap......

bearfoil 21st May 2011 18:00

ChristiaanJ

"...I respect the BEA for not being suckered into premature and incomplete statements, other than refuting the Figaro crap......"

On that we agree. :ok:

takata 21st May 2011 18:12


Originally Posted by bearfoil
Still, "Clean at impact"? "Clean all the way down"? If speed is a problem, dirty is good?

RTL still limited at this settings means no slats used all the way down as, if used, its settings would be quite different from Mach 0.80/272 kts. IMO, it also means that two ADRs were turned off after ADR disagree and that this fault was not cleared. No flaps, spoiler at impact is no proof they were not used at one point, but no proof either of any use and later retractation.
If two ADRs (with blocked pitots) were considered reliable by the crew, then turned ON at any point, they could not have remained frozen from FL350 to sea level, hence, at one point in the descent, the airspeed displayed would have been the "real" one and it would certainly not be 272 kts at impact (as shown by RTL) following the BEA description.

RR_NDB 21st May 2011 18:26

Managing an important and sensitive issue for France
 
Originally posted by ChristiaanJ


That is a fairly normal procedure, so why "will it not happen"?"
A "SIM picture" (complete or even a fraction) i guess will not go public now.

PR is critical now. The decision making, IMHO is being made at gov´t level.

The global picture with all details will be available in the end.

I will not here comment on "why is being managed this way", for many reasons.

wozzo 21st May 2011 18:31


Originally Posted by bearfoil (Post 6464917)
BEA is not the only authority responsible for conclusions. If the data is disclosed, "duty" can be assumed by any independent. You are confusing duty with ownership. The findings, though ennabled by BEA, are not the property of BEA. Likewise, "proprietary" or "Patent" considerations are secondary to Public good, would you not agree? National security perhaps, but what about Public carriage has to do with espionage?

I talked neither about duty nor responsibilty (I agree, anyone should have the opportunity for taking that on themselves), but mandate (by law - remember, there are judicial proceedings going on). As to reasons for non-disclosure: that was meant in an abstract way. I'm not completely sure that the complete CVR should be published (there may be non-essential parts to be kept back out of respect for the deceased and their families), but DFR data - dump them into the public domain!


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