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AF 447 Thread No. 7

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AF 447 Thread No. 7

Old 8th Apr 2012, 17:18
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Good news must be "broadcasted" ASAP or IMMEDIATELY

Hi,

The System could also provide good news to the crew.

May be (the System) should ASSERTIVELY inform to a hard working crew submitted to uncertainties (as in Thiells B727 and AF447) IMMEDIATELY when the Air Speed (and related indications) became reliable again.

IMO UAS and Reliable Air Speed (RAS ) should not be programmed by Designers as a System "inside information". Better to communicate BOTH.

The anomaly came from just the sensors (OBSOLETE). Not even (caused) from ADM, etc.

The confidence in the System (of great importance) MUST BE PRESERVED!

("Good news" in Easter day )
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Old 8th Apr 2012, 18:21
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"Guarantee?" Yes, you'll want marketing, down the Hall, but they're out golfing.

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Old 9th Apr 2012, 11:53
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@ RR_NDB:
While I agree that the system could also provide good news to the crew, I don't think your example is pertinent.
Indeed, the system has to be sure of itself to provide news (particularly good news such as: you now can rely on...)
The current logic is: The fact that the 3 airspeed sources give ~ the same value is an indication that this value is correct as long as no error occured.

As soon as an error occured (and until a system reset on the ground, with a check of its sources), the system is no more able to determine if what it "senses" is true or not.
You can easily imagine that 3 frozen/clogged pitots will at some time indicate ~ the same (incorrect) airspeed value. It would be very dangerous to rely on that (incorrect) value.
I know that ice eventually melt, but ice is not the only potential problem encountered by the pitots. What about volcanic ashes, for example?

Hence it's far safer IMO to let the crew do its job, as pilots: Assess the failure, eventually see that the values ​​seem correct again and decide to give them (or not) (limited) confidence. In the mean time, fly pitch&power, which can be done without relying on airspeed indications.

Regards.
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Old 9th Apr 2012, 14:34
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Stunning discussion by some very smart people. Puts me in mind of "Dark Star".

"No, no, Doolittle, you talk to it.
Teach it Phenomenology, Doolittle."
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Old 9th Apr 2012, 16:07
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Originally Posted by PJ2
Also, I do not buy the sidestick vs control column argument one bit. Any pilot watching the pitch attitudes seen here does not need sidestick or column position to tell him/her that something extremely serious is about to happen if control of the aircraft isn't taken over immediately and the nose lowered to normal cruise attitudes.

This is the part that is very definitely not complicated.
As you know ... I sincerely disagree here, the sidestick vs control column argument is a serious one and cannot be discarded from the equation that helped to the final result.
I would agree the argument is not making a difference regarding the initial pitch up as the displacement of the sidestick was limited as would have been such displacement of a control column, but the difference is later on especially when the cpt came back.
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Old 9th Apr 2012, 16:37
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t

When he was telling Bonin (PF) CLIMB!, what was the other pilot seeing? BECAUSE, as we know, BONIN was holding NOSE UP, he said so. He was PF, and yet the other pilot said CLIMB? Didn't HE SEE THE DISPLAYS?

"But I have been holding NOSE UP". Tell us again the displays were working?

Why did PF have to TELL anyone he was commanding NU?

This tells us Number One: No one knew (except RHS!) RHS STICK POSITION.

NUMBER TWO, with the a/c commanded NU, how did the others not see this on the displays?

NO ONE knew the attitude. For THREE, BEA stays quiet after ""I have no displays" (When Captian enters). We must assume NO DISPLAYS came back, ever.....

PILOT A: "Climb, Climb"

PILOT B: "NO, Do Not Climb"

PILOT C: "But I have been holding NOSE UP for some while"

None knew attitude. What display?

These are discussions of what they should do with the CONTROLS. And they are clraerly confused. FOR ONE, they know they are plummeting down, For Two, they are guessing at which way to cammand the NOSE. How can PNF tell "CLIMB", if he know the a/c is PITCHED UP at 17 degrees? The displays are not working, and they are trying to suss anything that will stop the descent, without knowledge of NU, clearly.

Last edited by Lyman; 9th Apr 2012 at 18:15.
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Old 9th Apr 2012, 23:34
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Angel Homage in aerospace HMI

AT THE TOP OF THE EVEREST OF MAN-MACHINE INTERFACE , I pay tribute to TEST-PILOTS , and TEST-INGINEERS who offer their lifes to improve Air Safety, and I also pay homage to TEST-PARACHUTISTS WHO TEST THEIR ZERO-ZERO EJECTABLE SEATS at price of their own health.

Maybe it is the worst fault of Airbus to have used airline pilots to test A330 also killing the test-pilot Nick Warner, and passengers confronting stall in AF447.

1994 A330 test flight crash - Wikipedia, the free encyclopedia
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Old 10th Apr 2012, 00:44
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roulishollandais,

I cannot distinguish many similarities between the crash of 1994 and AF447. Care to elaborate?

I sincerely hope I misunderstood your point, and that this is not (airbus) bashing disguised as a tribute (to test crews).

PS: Do humans still test (0/0) seats? Last time I checked, dummies ruled.
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Old 10th Apr 2012, 01:06
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I don't think your example is pertinent.


I will comment reasons to mention these flights in the example:

1) PF's stalled their planes

2) Pitot's issue triggered the sequence of events

3) Stall caused LOC or (non recoverable situations)

4) They didn't identified AS issue (due icing)

5) Redundant indications were not enough. Result: Confusion and misleading

(In Thiells case a misleading was obvious. In AF447 "lack of minimum understanding" seems a fact. (based in what we have) Confusion seems to be resulted. When you are fed with REDUNDANT erratic indications a "misleading" occur: Reduce (or destroy) your confidence in the System you is operating. And open new possibilities.

Yes, there are some (imo minor) differences, i agree: 727 heater off, 447 obsolete Pitot's, 727 stall then LOC, 447 full stall: net result, an amazing* LOC. This 2 crashes has IMO more commonalities than other possible examples. Yes, every accident is unique.

Indeed, the system has to be sure of itself to provide news (particularly good news such as: you now can rely on...)
AZR, i am "technically oriented". But, this "non technical value" (confidence) is of extreme importance. I don't like the scenario of a crew with no confidence on the "interface" (even partially). This is very dangerous and can led to "dramatic" possibilities.

It would be very interesting to understand the current approach in "detail" (algorithm). Can be in "managerial" level. An outline. Maybe A33Zab could also help on this.

As soon as an error occured (and until a system reset on the ground, with a check of its sources), the system is no more able to determine if what it "senses" is true or not.
I may ask: Why? Frankly, IMO there are better approaches. This "long latch" (long outage) and "reset on ground" tells me: Room for improvement.

You can easily imagine that 3 frozen/clogged pitots will at some time indicate ~ the same (incorrect) airspeed value. It would be very dangerous to rely on that (incorrect) value.
DSP techniques (very common) and good algorithms solve this easily. Typical engineering problem that instrumentation (industrial) engineers has full capability to deliver "State of the art" implementation. No problem! Remember, you process the signal (normal), the onset of "garbage generation and the recover of the Pitot's normal operation. (447 case). In Thiells 727 perhaps plane crashed with 3 tubes frozen. (we don't know). An interface probably never would provide "good news".

I know that ice eventually melt, but ice is not the only potential problem encountered by the pitots. What about volcanic ashes, for example?
Good question. Before clogging (i mean, during transitory) DSP easily detect. Probably tubes will be no longer operational, thus creating a more serious scenario. Fortunately NOTAM's solve this. There is no "instant" ash. like 447 crew faced after entered WX. So, ash, no problem: Same DSP, same approach. (long latch for other reason)

Hence it's far safer IMO to let the crew do its job, as pilots: Assess the failure, eventually see that the values
I will continue (editing) in few minutes. But i anticipate: "Globally speaking" i.e. looking to all factors (reliability, crew "workability" on the issue (assessment, cross checking (as mentioned paper put) my feeling is: Better to review current approach.

As lomapaseo IIRC well put (as i understood his post). WE could, should (quasi must) post our engineering POV. Safety is our ultimate goal. (It's my agenda, my reason to think, to analyze, to read, etc. here in PPRuNe)

* The AF447, LOC seems unique in (commercial airliner) aviation history. No abnormal attitude, and only a long and slow RH turn. (Even "G protected" during the zoom climb), Indeed unique? I don't remember nothing similar. (Unless the ROD is considered an abnormal attitude, may be of a new type )

Last edited by RR_NDB; 10th Apr 2012 at 18:29. Reason: Text impvmt
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Old 10th Apr 2012, 01:08
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Further Details of Test Flight Crash

This link shows much more detail about what went wrong. Draw your own conclusions as to what Mr. Hollandaise had in mind:

ASN Aircraft accident Airbus A330-321 F-WWKH Toulouse-Blagnac Airport (TLS)
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Old 10th Apr 2012, 01:50
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Hi,

Mac the Knife

"Dark Star"



While attempting to repair the [email protected], Talby is blinded and inadvertently triggers a more serious problem, causing extensive damage to the ship's main computer and a major malfunction with Thermostellar Bomb #20, which, on arrival at their target planet, becomes belligerent and refuses to obey orders and drop from the bomb bay.

Last edited by RR_NDB; 10th Apr 2012 at 02:12.
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Old 10th Apr 2012, 03:28
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Thanks for your PM Lyman.
I can't tell there was an issue with the attitude indicator(s) but it is a possibility there was one or they thought there was one as they choose to manipulate the ATT HDG switch or is it the way it is teached at airfrance to turn simultaneously both AIR DATA and ATT HDG switches ...
For sure there was confusion, big time, and those invisible sidesticks just contributed to that confusion.
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Old 10th Apr 2012, 13:12
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It has been suggested by the BEA that On na pas une bonne annonce de et de vitesse were going together but most probably they don't as they are separated by 4 seconds and the translation made is incorrect : Usually une annonce is not a display but an announcement made through a public aural system.

Annonce furtive ou persistante "STALL" (Appendix 3 in IR3)

IMO the PF was telling that the STALL WRN that came up one second earlier was a false one.



Last edited by CONF iture; 10th Apr 2012 at 13:57.
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Old 10th Apr 2012, 14:29
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Cool

Hi,

It has been suggested by the BEA that On na pas une bonne annonce de et de vitesse were going together but
This is not the first time differences (significant) were detected between the versions (English and French) in the preliminary report No. 3 and cause confusions
Announcing and displaying are two different things with different meanings
So .. what is the true word ? the one in the french version or the one in the english version ?
It does not add anything positive to the professionalism of BEA when it comes to communicating
It seems amazing that BEA can't ensure the service of a translator familiar with the aeronautics language as they have sufficient funds
It will be interesting to scrutinize carefully the two versions of the final report (if it is translated into English)
BTW .. stay that the BEA is french and so the original publishing (in french) must be considered like official release
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Old 10th Apr 2012, 15:27
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Confidence is the greatest asset of any successful enterprise...*

Hi,

CONF iture:

I will comment on that (well observed and likely) probable fact on:

Man-machine interface and anomalies
thread, on the ramp "being fueled".

Mac

I hope the improvement of "interface" crew currently use in "advanced planes" (all types) in the aftermath of AF447 HOW, WHY, analysis and subsequent "works".

* Albert Schweitzer
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Old 10th Apr 2012, 15:31
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CONF iture, jcjeant,

"On n'a pas une bonne annonce ... de vitesse" cannot imply anything else than a display AFAIK. What do you have in mind, regarding an "announcement" ??

I agree that the term is not the more common in french ("on n'a pas une bonne indication" seems better suited) but remember it was the middle of the night and the beginning of troubles. Using "une annonce" in place of "une indication" doesn't surprise me that much (french is my native language).

I really don't think the BEA is to blame, here, unless wanting to quibble about everything it writes.
I insist on here, because sometime translation issues are real, and may lead to misunderstanding and/or nonsenses.
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Old 10th Apr 2012, 15:36
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Man machine interface

I hope this is being addressed by BEA with the right* emphasis.

I would agree the argument is not making a difference regarding the initial pitch up as the displacement of the sidestick was limited as would have been such displacement of a control column, but the difference is later on especially when the cpt came back.
"but the difference is later on especially when the cpt came back."




* right means, IMO relevant
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Old 10th Apr 2012, 16:00
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Snoop

Originally Posted by AlphaZuluRomeo
Do humans still test (0/0) seats? Last time I checked, dummies ruled.
May be they no more do. I thought in the 90's it was already the case., But I had to wonder one of my friend, CLAUDE JOHARY, had to test a Mark-IV (type to be confirmed) from the ground. After what I had some problems with his back, and could no more apply as astronaut. He died in 1995 as passenger.
MS.760 Paris 11 Octobre 1995 - Uzech - Arostles

Originally Posted by AlphaZuluRomeo
I cannot distinguish many similarities between the crash of 1994 and AF447. Care to elaborate?
The ONLY similaritie I want to point out is the non adequate man on the non adequate place ; and that concerns HMI.
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Old 10th Apr 2012, 16:17
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RR_NDB:

Quote:




Indeed, the
system has to be sure of itself to provide news (particularly good news such as:
you now can rely on...)
AZR, i am "technically oriented". But, this "non technical value"
(confidence) is of extreme importance. I don't like the scenario
of a crew with no confidence on the "interface" (even partially). This is
very dangerous and can led to "dramatic" possibilities.


It would be very interesting to understand the current approach in "detail"
(algorithm). Can be in "managerial" level. An outline. Maybe A33Zab could
also help on this.
If i understand your question correctly,

'Good news' is if ECAM message/action is properly handled, understood and cleared by crew.

VERY good news is if ECAM message or FLAG is cleared by the system itself because that means the anomaly is not present anymore.

For the speed indication it is more difficult:
but they are in view (ADR 3 standy/isis and selectable to show on any PFD)
so if they are consistent again after anomaly the crew will know UAS is not present anymore.
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Old 10th Apr 2012, 16:36
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Originally Posted by CONF iture
Usually une annonce is not a display but an announcement made through a public aural system.
An 'annonce' can be in writing, e.g. the small ads in a newspaper. Good point, nevertheless.
Found this in the "Lexique-bilingue" on the Dassault-Aviation website:

ANNONCIATEUR DE MODE DE VOL: FLIGHT MODE ANNONCIATOR (FMA)
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