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  • Evan
    replied
    Originally posted by 3WE View Post
    No, and listen carefully- we object to cowboy improvisation that goes against "all" logic and fundamentals and procedures.
    Improvisation never goes against all logic. The question is: is the logic sound? The next question is: Is there something deceiving behind the logic?

    Written and memorized procedures are reliably sound. They defend against deceiving things.

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  • 3WE
    replied
    Originally posted by Evan View Post
    Wait a sec... did 3WE hack your account?
    No, and listen carefully- we object to cowboy improvisation that goes against "all" logic and fundamentals and procedures.

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    But if you want to know what I really think, this is an ideal situation for a "gimme my plane" guarded switch and then you don't need to turn off any ADR ever in any unreliable speed situation, and you can keep monitoring the 3 airspeed indicators and when the situation is over (if ever) you turn off that guarded switch and give control back to HAL.
    Wait a sec... did 3WE hack your account? The system is designed to "give you the plane" and that's where it all begins. The final report concluded that the airplane responded perfectly to commands. Aside from protections and the other aspects that were lost (indicated on ECAM), the FBW was not affected, and if it were, Airbus would have designed it to degrade as well. Because it isn't 'HAL' and regulators were very very very demanding in overseeing its development. If only that were true of Boeing...

    The point is still the point. I can see no purpose to divert CRM to an ADR CHECK procedure, which is actually counter-productive in a situation where the problem resolves itself in a minute or so. The problem wasn't well understood in 2006, but it certainly is now, and it does need its own procedure to follow which does not have at least one pilot distracted on a fool's errand. Perhaps we are not looking in the right place, or perhaps the industry just never took the lesson seriously, or just lacked initiative.

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  • Gabriel
    replied
    Originally posted by Evan View Post
    I understand that, but the scenario we are talking about begins with sudden loss of autoflight and reversion to alternate law, followed by the recognition of unreliable speeds. At this point, there is no such danger. Where is the procedure for this event?
    I don't know the full ramifications, what other things may be affected by 2 matching unreliable ADRs. Autotrim, elevator gain (roll is direct law but pitch is still G-on-stick), stall warning, FD...

    Plus, you cannot establish a procedure for each way each thing can fail. Can the procedure be improved? Maybe, I won't argue that.

    But if you want to know what I really think, this is an ideal situation for a "gimme my plane" guarded switch and then you don't need to turn off any ADR ever in any unreliable speed situation, and you can keep monitoring the 3 airspeed indicators and when the situation is over (if ever) you turn off that guarded switch and give control back to HAL.

    Leave a comment:


  • 3WE
    replied
    Originally posted by Evan View Post
    The automation and protections are already lost. They can't survive total pitot failure. You know this.
    ...and yet pilots can survive using basic stuff...oh the ironing...you have disdain for this.

    On a different angle, are we making any progress?

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  • Evan
    replied
    Originally posted by Gabriel View Post
    But they can survive 2 pitots giving incorrect but consistent data. That is what you try to avoid and hence turn any 2 ADRs off (but leave 1 on to keep monitoring it).
    I understand that, but the scenario we are talking about begins with sudden loss of autoflight and reversion to alternate law, followed by the recognition of unreliable speeds. At this point, there is no such danger. Where is the procedure for this event?

    Leave a comment:


  • Gabriel
    replied
    Originally posted by Evan View Post
    The automation and protections are already lost. They can't survive total pitot failure. You know this.
    But they can survive 2 pitots giving incorrect but consistent data. That is what you try to avoid and hence turn any 2 ADRs off (but leave 1 on to keep monitoring it).

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    It is written there in the very procedure in the link I provided.
    If the unreliable ADRs cannot be identified yo have to switch off 2 of them to avoid that the automation / protections take as valid 2 incorrect but consistent values (even to the extent of discarding the third and possibly only correct one).
    The automation and protections are already lost. They can't survive total pitot failure. You know this.

    Leave a comment:


  • Gabriel
    replied
    Originally posted by Evan View Post
    Still, why monkey with the ADRs?
    It is written there in the very procedure in the link I provided.
    If the unreliable ADRs cannot be identified yo have to switch off 2 of them to avoid that the automation / protections take as valid 2 incorrect but consistent values (even to the extent of discarding the third and possibly only correct one).

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    This procedure that you pictured is specific for BUSS equipped airplanes. Two clues that this is the case:
    - Note the text below the bottom yellow highlighted line.
    - Note the "new procedure" (back then) in page 17 of the same document. It has the pitch/thrust tables, which do not exist in the version you posted because you don't need pitch and thrust tables when you have the BUSS speed tape and GPS altitude displayed in the PFD.
    And this procedure is the one implemented 3 years before AF.
    The one I posted, I believe, is more modern.
    Still, why monkey with the ADRs?

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  • Gabriel
    replied
    This procedure that you pictured is specific for BUSS equipped airplanes. Two clues that this is the case:
    - Note the text below the bottom yellow highlighted line.
    - Note the "new procedure" (back then) in page 17 of the same document. It has the pitch/thrust tables, which do not exist in the version you posted because you don't need pitch and thrust tables when you have the BUSS speed tape and GPS altitude displayed in the PFD.
    And this procedure is the one implemented 3 years before AF.
    The one I posted, I believe, is more modern.

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Again, where does that come from? Show me.

    Because what I see is, in case of not being able to identify one reliable ADR, above FL250 switch any 2 of them off (the remaining one cannot be used by any automation or speed-based protection since it HAS to consider it unreliable, but the pilots can monitor the resulting airspeed and, when/if it makes sense again, they can try to switch the other ADRs on and compare), and below FL250, IF THE SPEED IS STILL UNRELIABLE, it calls to switch all ADRs off IN ORDER TO ACTIVATE THE BUSS. I wonder how this procedure looks like in non-BUSS airplanes. I also wander why Airbuss doesn't want us to use the BUSS above FL250.

    http://flightacademy.info/wp-content...-procedure.png

    [ATTACH=CONFIG]27204[/ATTACH]

    I suspect that this is the current procedure, not the one in use at the time of Air France (which was also non-BUSS so this procedure would not apply anyway)
    Inconsistencies...

    I don't think the "new" combined 'Unreliable Speed Indication / ADR Check' procedure is BUSS specific. Note the yellow highlighted parts:

    Click image for larger version

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    Again, shutting down ANY ADR's seems counterproductive for the AF447 scenario.

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  • Gabriel
    replied
    Originally posted by Evan View Post
    AFAIK, every ADR CHECK PROCEDURE calls for shutting down any ADR that is faulty (providing erroneous airspeed data), so, when all speeds are erroneous, all are shut off. Also, this isn't the ACTIVATE BUSS PROCEDURE, it is the UNRELIABLE AIRSPEED PROCEDURE.
    Again, where does that come from? Show me.

    Because what I see is, in case of not being able to identify one reliable ADR, above FL250 switch any 2 of them off (the remaining one cannot be used by any automation or speed-based protection since it HAS to consider it unreliable, but the pilots can monitor the resulting airspeed and, when/if it makes sense again, they can try to switch the other ADRs on and compare), and below FL250, IF THE SPEED IS STILL UNRELIABLE, it calls to switch all ADRs off IN ORDER TO ACTIVATE THE BUSS. I wonder how this procedure looks like in non-BUSS airplanes. I also wander why Airbuss doesn't want us to use the BUSS above FL250.

    http://flightacademy.info/wp-content...-procedure.png

    Click image for larger version

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    I suspect that this is the current procedure, not the one in use at the time of Air France (which was also non-BUSS so this procedure would not apply anyway)

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Ok, that is a good point. But what procedure calls for all ADRs off? This is required to activate the BUSS only (if installed) AFAIK.
    AFAIK, every ADR CHECK PROCEDURE calls for shutting down any ADR that is faulty (providing erroneous airspeed data), so, when all speeds are erroneous, all are shut off. Also, this isn't the ACTIVATE BUSS PROCEDURE, it is the UNRELIABLE AIRSPEED PROCEDURE. On BUSS-equipped aircraft, BUSS activation is just the automated result of shutting down all the ADRs. But why would you run ADR procedure for unreliable speeds caused by a common environmental phenomena temporarily contaminating the pitots? It's counterproductive. It will delay or prevent the restoration of airspeeds and autoflight. Why would you shut down ANY ADR in this situation?

    Recall that, prior to AF447, Airbus considered the air data system to be very robust due to its multiple redundancies, but didn't seem to fully consider a common environmental vulnerability (ice crystal ingestion at cruise) that renders all that redundancy useless. In the wake of the crash, I expected a new procedure to defend against this newly-revealed threat, to prevent errors and defend against deceptions. So where is it?

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  • Gabriel
    replied
    Originally posted by Evan View Post
    The point I am making: where is the procedure for this? Why would you go directly to an ADR fault identification procedure when there is no ADR fault? Why would you shut down all your ADR's when you want to get the speeds back asap? Why would you disable your air data systems when they typically restore themselves in a minute or so? What you want to do is manually stabilize, reconfigure certain deceptive systems and remain in stable flight for approx one minute until the pitots clear and the speeds become reliable again and you can restore autopilot. This is ice ingestion at cruise level in conditions where that can occur, typically in the ITCZ, a failure scenario that is now known to exist. Where is the procedure for that?
    Ok, that is a good point. But what procedure calls for all ADRs off? This is required to activate the BUSS only (if installed) AFAIK.

    Leave a comment:

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