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AF 447 Search to resume (part2)

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AF 447 Search to resume (part2)

Old 21st May 2011, 18:35
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bearfoil
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Access. Somewhere between "Ere, let's 'ave a look?" and by subpoena.

In this case, and others, access by Court order is sufficient. Other than that, a standard "FOIA" should do nicely. And does. No one I know has demanded release of raw data, as yet. There are still missing some traces from the final minute of Perpignan, however.

Academic access? Certainly, and provided for. Access for commercial reasons? Probably, and unavoidable.

Accident results are in the Public domain, suredly.
 
Old 21st May 2011, 19:07
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Originally Posted by bearfoil
In this case, and others, access by Court order is sufficient. Other than that, a standard "FOIA" should do nicely. And does. No one I know has demanded release of raw data, as yet. There are still missing some traces from the final minute of Perpignan, however.
You are really talking like a lawyer and one who is already working his case, something completely unrelated with those investigation findings. Now, tell us a bit more about your sources implying a Perpignan cover-up?

Or, maybe that this quote is for enlighting your claimed "objectivity"!

Public domain: those data are under justice control and nothing will be in the public domain until this case is fully settled. Only declared parties can access it. As for the raw data, NTSB, AAIB, etc. are fully involved beside the BEA with this analysis process.
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Old 21st May 2011, 19:08
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Originally Posted by bearfoil
[/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.
The problem is that CONF iture, among others, is working from a pre-determined conclusion - that the BEA is to some extent in the pockets of Airbus and Air France - and thus one would always have to question whether this pre-determined conclusion would affect his reading of the data in any way.


Originally Posted by RR_NDB
There is room for (low cost) improvement in existing CVR´s.
But at what cost in terms of engineering complexity? The more components involved, the higher the complexity, and the higher the probability of component failure. This is one of the first axioms we learn as engineers.
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Old 21st May 2011, 19:14
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Cool

Hi,

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)
ublic domain: those data are under justice control and nothing will be in the public domain until this case is fully settled
The BEA is not part of the court process.
The BEA is making an technical investigation that is completely separate from the judicial power
As tell the BEA itself .. they are not there for blame anyone.
And be sure that the final BEA report will be published long time before any judicial process begin (like Concorde case)
It is not required (no laws) to maintain silence as it is the case for those involved in the court process.
Judicial:
Another technical investigation will be conduct by judiciary experts

Last edited by jcjeant; 21st May 2011 at 19:26.
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Old 21st May 2011, 19:31
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RTLU found "coherent" with cruise setting

BEA Interim report #2, pg 27:

The RTLU was found in its place in the fin and disassembled. An examination
was performed at the manufacturer’s and showed that it would allow travel
of the rudder measured as 7.9° +/- 0.1°. As an example, at FL350, this travel is
obtained for Mach 0.8 +/- 0.004, corresponding to a CAS of 272 +/- 2 kt.
Suppose they used slats (thus enabling change of RTLU settings)

Question: The info obtainable on the RTLU would be (high probability) different or could be the 7.9° by "chance"? The RTLU mfr. had this info "from a memorized mechanical freeze" of a mechanical limiter? Or other method?
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Old 21st May 2011, 19:37
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The decoding document, supplied with this airplane, has around 1,300 parameters. Not all of them are relevant or necessary for an understanding of the causes and circumstances of this accident. The reporting will understandably be limited to those that are. From the BEA website:
In accordance with Article L731-3 (French Law n° 99-243 of 29 March 1999), the BEA « makes public at the end of the technical investigation a report in a form appropriate to the type and seriousness of the event. This report does not mention people by name. It uses only information from the investigation necessary to determine the circumstances and causes of the accident or incident and to the understanding of safety recommendations.
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Old 21st May 2011, 19:47
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Hi,
Originally Posted by jcjeant
The BEA is not part of the court process...
This is irrelevant. The BEA is fully mandated by the law for investigating those data which are staying (from the begining) under judiciary control (those Gendarmes are in charge of the recorders and a judiciary police officer is always staying with them). So, the BEA doesn't own those "evidences" and work on them following its mandat. What is released for the public is in the BEA report, as per the law.
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Old 21st May 2011, 19:53
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Cockpit sound analysis

DozyWannabe,

But at what cost in terms of engineering complexity? The more components involved, the higher the complexity, and the higher the probability of component failure. This is one of the first axioms we learn as engineers.
I reiterate: At a very low cost. Let´s segment qualitatively first:

1) R&D: Very low cost.
2) Product Engineering: Low cost (We could quantify)

The integration to existing structure i estimate to be not a relevant issue.

I posted this possibility with all implications previously "self questioned" (this forum requires a fascinating degree of attention).

About "Circuitry complexity and Failure Rate" we could implement a better one with less components and simpler circuitry, just using denser Integrated Circuits.

In summary, The cost/benefit IMO is good for an improvement. For an investigator "High Quality recording of facts" is obviously good.
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Old 21st May 2011, 19:59
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Cool

Hi,

This is irrelevant. The BEA is fully mandated by the law for investigating those data which are staying (from the begining) under judiciary control (those Gendarmes are in charge of the recorders and a judiciary police officer is always staying with them). So, the BEA doesn't own those "evidences" and work on them following its mandat. What is released for the public is in the BEA report, as per the law.
You right .... this material (the black boxes) are exhibits to the prosecution of the court process.
The BEA report (the result of their analysis) is not an exhibit.
It therefore not falls under the same sections of law protecting the exhibits.
That's the point I want to put emphasis (BEA report is not part of the judicial process)
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Old 21st May 2011, 20:03
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FBW Stick Philosophy

Garage Years:

Also, my understanding of the side-stick is that the Airbus stick is quite a different design to that of the F-16. The F-16 stick only moves a very small physical deflection and is more of a force sensor (I worked F-16 simulators about 17 years ago!), while the 'bus stick is a position sensor. That in itself though is merely interesting.
This puzzles me a bit. Decades ago when I was a student at Navy Test Pilot School, we were given three flights in a highly-modified "variable-stability" B-26 operated by Cornell Aeronautical Laboratories (later called Calspan). The right seat was truly FBW. Right seat control response was determined exclusively by analog computers. Students were asked to evaluate the response in various configurations. One configuration was to have the stick (or yoke, I can't remember which) move large distances for small control surface movements but with little force required. The opposite configuration was to have the stick "locked in concrete" and all control surface movements responding only to stick forces. My instructor, Nello Infanti, asked which I preferred. I preferred minimal stick motion with aircraft response determined by stick forces. Nello informed me that the vast majority of pilots also preferred that configuration. I would think that, when finding it necessary to fly current FBW aircraft using the stick, that precise control would be more difficult using stick deflection rather than stick forces. Is Garage Years correct in his characterization of the AB side stick?

(See Nello's obituary here: Nello Infanti Obituary: View Obituary for Nello Infanti by Dengler, Roberts, Perna Funeral Home, East Amherst, NY )
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Old 21st May 2011, 20:11
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DJ77
Was not the BEA just meaning it is not yet determined whether the ULBs did transmit or both failed ?
Having had another look at the French, and guided by your interpretation, I believe you are right. Thanks.
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Old 21st May 2011, 20:12
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Originally Posted by RR_NDB
Suppose they used slats (thus enabling change of RTLU settings)
I certainly can't suppose they used slats after RTL freeze. In this case, the RTL would be at its full limit settings (no speed limit). Either this plane was flying at 272 kts at impact, either it was left frozen from 0210.
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Old 21st May 2011, 20:30
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takata

It is not possible to determine as yet? The record of control deflection is at hand? If rolling and or yawing, and the Rudder was frozen at ~ 4degrees each way, unlocking it by manual action might have been tried. We'll soon see. I think we'll get an education as to how the Rudder and Pilot interface in the weeds, also. Unlocking the Rudder seems a poor choice?
 
Old 21st May 2011, 20:37
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bearfoil
If rolling and or yawing, and the Rudder was frozen at ~ 4degrees each way, unlocking it by manual action might have been tried.
A small factual error - one I believe you have committed before.

The RTLU set the travel to +/- 7.9° or a 15.8° "sweep" if you want it that way.
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Old 21st May 2011, 20:52
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Originally Posted by RR_NDB
About "Circuitry complexity and Failure Rate" we could implement a better one with less components and simpler circuitry, just using denser Integrated Circuits.
But aren't denser IC's just moving the complexity "up the chain", as it were? Denser IC's also tend to generate more heat energy, so the new components would have to be re-certified - an expensive and time-consuming process.

Complexity and lack of predictability in new hardware is the reason that digital circuitry introduced in aviation tends to be of the simpler "tried and true" designs (which would be considered obsolete in terms of consumer devices) rather than the latest generation hardware - it's also the reason I throw my hands up in the air every time I hear FBW/FMC avionics systems compared with modern PC computer technology.
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Old 21st May 2011, 21:10
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Originally Posted by takata
I certainly can't suppose they used slats after RTL freeze. In this case, the RTL would be at its full limit settings (no speed limit).
The FCOM description of the rudder travel limit is ambiguous on this point. Slat limit speed is 240 kCAS, and it would seem illogical for the maximum rudder deflection with slats extended to be independent of speed. Could it be that the 'freeze' is lifted, and the normal limits apply? (I.e. 35 deg below 150 kCAS).

Last edited by Jetdriver; 21st May 2011 at 23:06.
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Old 21st May 2011, 21:35
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It's not ambiguous at all. RT Limits are computed and limited by both sec's. If both sec's fail the RTLU remains frozen at the limit in use upon failure.

Now lowering the slats won't repair the sec's so the statement is quite logical. Lower the slats and you have max deflection again (35 degrees)
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Old 21st May 2011, 22:15
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So. What happens to the Rudder Travel if unlocked. Can it be re-Limited?

Or, with SECs still out, does it lock at whatever travel it had at new Lock? (including deflected?)

Can it lock at 17 degrees? Can it be re-centered and locked?

What does DIRECT LAW do to RTL ? Does it release it?
 
Old 21st May 2011, 22:17
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Now lowering the slats won't repair the sec's so the statement is quite logical. Lower the slats and you have max deflection again (35 degrees)
At < FL200 and < 150 KCAS the slats/flaps are available. Should the PRIMS/SECS be available, then it should be reasonable to expect the RT limit to be calculated as per normal. Otherwise, +/- 35° would seem to be the fall back compromise.

The RTLU setting was as a result of reversion to ALT2 Law, and whether other PRIM/SEC problems have intervened, or whether valid KCAS was available is simply guesswork.

EDIT :: Should the slats be extended as allowed below FL200, then any preset RTLU setting will not be cleared until < 150 KCAS, at which point the limit will be +/-35° and reducing if the KCAS increases again.

Last edited by mm43; 22nd May 2011 at 02:46. Reason: disambiguation
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Old 21st May 2011, 23:13
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K.I.S.S. should be a design rule, when possible

Hi,

First, i will use some words of a phrase you posted:

I throw my hands up in the air every time I hear FBW/FMC avionics systems
To say you what happens to me when i realize the "circuitry" amount and complexity used (required) in highly complex FBW a/c.

Just a detail: You need to use 3X (acting as 5X) redundancy. Approaching the one used in the STS fleet now retiring.

(Yesterday night i was reading again on the F8 DFBW. A MUST read)

Well,

But aren't denser IC's just moving the complexity "up the chain", as it were?
In this case, i would say: No. The complexity is about the same. And the use of more memory presents "no drawbacks".

Denser IC's also tend to generate more heat energy
We are talking about Audio (low power signals), so, no problem.

so the new components would have to be re-certified - an expensive and time-consuming process.
You are talking on the IC´s or the final product, the CVR? Anyway every change or evolution is not free. And ROI must be checked.



Complexity and lack of predictability in new hardware is the reason that digital circuitry introduced in aviation tends to be of the simpler "tried and true" designs
I agree 100%. And will use this to ask: What´s your feeling (on this issue) on the Revolution (rdware and Software/algorithms[/]) EA introduced using DFBW technology (for the first time in non military planes)? With it´s big implications. Why US didn´t introduce "in parallel"? But this is for another post or even another thread.

BTW, What is "wiring fault" (Hard) mentioned in some earlier posts regarding ACARS sent. I am curious to understand this.
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