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  • Gabriel
    replied
    Originally posted by Evan View Post
    No, but I'd bet loss of airspeed data would be one of them...
    Exactly my thought...

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Thanks.
    Any idea what this means (under Alternate Law, NOT abnormal alternate)?
    "Certain failures cause the system to revert to Alternate Law without speed stability."
    No, but I'd bet loss of airspeed data would be one of them...

    Leave a comment:


  • Gabriel
    replied
    Originally posted by Evan View Post
    Thjis link shows everything at a glance:

    http://www.airbusdriver.net/airbus_fltlaws.htm
    Thanks.
    Any idea what this means (under Alternate Law, NOT abnormal alternate)?
    "Certain failures cause the system to revert to Alternate Law without speed stability."

    Leave a comment:


  • Evan
    replied
    EDIT TO ABOVE: The engine anti-ice switches were selected ON at 2 h 10 min 03. The #1 engine anti-ice ON was recorded on at 2 h 10 min 05—exactly the moment of the auto-pilot failure. The switches are located on the overhead panel. Because there was no verbal callout for this, it is unclear as to which pilot makes the selection (it could be the exchange at 2 h 10 min 02 - PM: "Go on?", PF: "Go ahead".) But If the PF has made this selection instead of the PM, his eyes would have been on the overhead at that critical moment. FURTHERMORE, the PF does not confirm that continuous ignition start is active until almost 5 seconds after taking manual control. FADEC switches ignition to the continuous mode (ENG START) automatically after the ENGINE ANTI-ICE is selected ON and this would be confirmed by an IGNITION indication on the memo section of the E/WD**. Since the PM never acknowledges his request for continuous ignition, this suggests that the PF's eyes were focused on the E/WD at that moment and perhaps for the entire first five seconds!

    I think, as they began to encounter significant ice crystals (recorded on the CVR as increased cabin noise), the PF was primarily concerned with the engines flaming out and not focused on the task of manual flight.

    Here's the sequence again:

    -
    2 h10 min 04,6
    Do you us [sic] to put it on
    ignition start?

    -
    (no answer from the PM)

    -
    Either pilot could have selected this using the rotary switch but this is not recorded on the FDR, leading me to believe the switch was not used.

    -
    2 h10 min 05 - the engine anti-ice switches are selected ON on the overhead panel. In the same moment the autoflight is lost (calvary charge)

    -
    Simultaneously, the engine anti-ice is recorded on. This would cause FADEC to automatically engage the 'engine start' in continuous ignition mode.

    -
    2 h 10 min 09,3 - almost five seconds after taking manual control, the PF says "engine start" (meaning: continuous ignition). If he means this as a confirmation of his own request and the rotary switch has not been selected (according to the FDR), his eyes must be on the E/WD IGNITION memo indication**. If so, he is possibly not focused on the instruments and the task of hand-flying.

    I think there might be something to this.

    **AFIAK The FADEC automatic continuous ignition mode is indicated on the memo section of the E/WD where the ENG A. ICE message is seen (see attachment, ignoring the fire indication of course).

    Leave a comment:


  • 3WE
    replied
    Originally posted by TeeVee View Post
    ...why not create a "staples easy button" for stall recovery that will work no matter what the computers are saying...
    PLEASE DO NOT SAY THESE SORTS OF THINGS WHERE GABRIEL MIGHT SEE THEM...THE POOR DUDE WILL GO OFF THE DEEP END!

    And in an attempt to help him- here's the short answer:

    1) Such procedures do exist.
    2) The FAA has recently changed procedures (likely in response to this and some other crashes), strongly towards these sorts of procedures.
    3) Don't tell Evan but the procedure works essentially the same for Piper Cubs and Boeing 777s.
    -The discussion for Airbii may be slightly more complicated- but the frightening truth is that the principles and procedures are the same.
    4) To further emphasize point #1, this general over-riding procedure has existed for a long long time.

    Indeed, a simple button!

    Gabriel: Count to 10, and please fill in the details I've glossed over.

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Could you provide a source please?
    Not that I don't believe you, but I want to investigate more.
    Gabe, I've attached two screen grabs from the FCOM because i'm too lazy to type them out.

    Leave a comment:


  • Evan
    replied
    One other interesting thing I just noticed...

    Immediately before the loss of autoflight, almost simultaneously with the calvary charge, the clearly concerned PF asks the more senior pilot...

    2 h10 min 04,6
    Do you us [sic] to put it on
    ignition start?



    He is asking if he should switch the ignition to 'continuous' IGN START (a provision against ice-ingestion flameout). Then, just after the AP is lost, after stating that he has manual control, the PF says...

    2 h 10 min 09,3
    Ignition start

    Is he answering his own question either because FADEC has automatically switched it to 'continuous' (due to the ENG ANTI ICE selection), or is he restating the request? In any case, he says nothing else until the first stall warning.

    I'm thinking he might have been focused on this task more than his hand-flying in the first few moments without eyes on the artificial horizon. Though hard to imagine, that might explain the initial upset.

    EDIT: See post below...

    Leave a comment:


  • Evan
    replied
    Originally posted by UncleFire View Post
    My "speculation" is that the PF didn't realize he was in Alt Law and figured the protections where still in place (among other things). Hence the near constant pulling back on the stick.
    It is certainly possible, as the left seat pilot (PF) was clearly not properly trained on type. But after pulling up initially and getting the stall warning the right seat pilot (PM) seemed to clue in a bit and told him to 'go down'. He did reduce pitch enough to avoid stall and silence the warning. At that point they could have still flown out it out. Now, about 10 seconds after losing autoflight, the PM finally has a look at the ECAM and announces that they are in Alternate Law. He also notices the thrust lock condition and resets the thrust levers to full climb. Now everything is going to be ok... but then PF inexplicably pulls up again and stalls the airplane.

    There are two clues telling him that they are in Alternate Law and have lost the stall protections. First, the PM has announced it; second, the master caution message: FLT CTL / ALTN LAW (PROT LOST) remains at the top of the ECAM window for at least the first 10 secs.

    There are two things working against these warnings. First, the crew has not followed a proper CRM process to quickly assess the situation, therefore they are not listening to each other clearly and seem to be cross-talking at that moment. It's possible that the PF did not hear him. Second, the PM never announces the 'protections lost' part of the message, so if this incredibly under-trained PF does not instinctively realize this fact from the announcement of Alternate Law, he might still think he has envelope protections. If so, it is consistent with the cause of the crash being grossly inadequate pilot training.

    Leave a comment:


  • TeeVee
    replied
    ok so obviously, it's been posited if not proven, that high altitude stall recovery should be a fairly basic and easy memory item for pilots to handle. however, as this instance and maybe some others (not sure) has proven, no everyone gets it.

    given the direction of more automation the industry is headed in, why not create a "staples easy button" for stall recovery that will work no matter what the computers are saying, that would operate/do exactly what the human pilot is expected to do--stop the stall: wings level, full power, what was it? 2 degrees nose up?

    Leave a comment:


  • UncleFire
    replied
    Originally posted by Evan View Post
    Thjis link shows everything at a glance:
    I lurk quite a bit on here-- and rarely post. This has been an interesting f/up discussion... anyway.

    According to your link. When in "Alt Law"

    A low speed stability function replaces the normal angle-of-attack protection
    ◦This command CAN be overridden by sidestick input. ---> which he was
    ◦The airplane CAN be stalled in Alternate Law. ---> which it was
    ◦An audio stall warning consisting of "crickets" and a "STALL" aural message is activated. ---> which occured
    ◦The Alpha Floor function is inoperative.

    My "speculation" is that the PF didn't realize he was in Alt Law and figured the protections where still in place (among other things). Hence the near constant pulling back on the stick.

    Pitch looked like it was around 10 deg for quite a bit and higher at times.

    I noticed that throttles were at near idle (or at idle) for a little bit there, then pushed all the way up (with the nose still up in the air).

    Were they so confused that not even the alt dropping like crazy didn't give them a clue that they were indeed stalled?

    Ok-- dumb question now. Don't they have GPS on those planes and given what was going on couldn't it have helped a bit w.r.t. how fast they were going (yeah, I know it would have been ground speed-- but still better than nothing)

    EDIT:
    Net-net-- I would have thought that one of the 3 in the cockpit at that point would have said follow the procedure (bunch of thrust and a little nose up, after the stall recovery of course).

    Leave a comment:


  • Evan
    replied
    Originally posted by Gabriel View Post
    Could you provide a source please?
    Not that I don't believe you, but I want to investigate more.
    Thjis link shows everything at a glance:

    http://www.airbusdriver.net/airbus_fltlaws.htm

    Leave a comment:


  • Gabriel
    replied
    Originally posted by Evan View Post
    Alternate law still retains artificial low speed stability.
    Could you provide a source please?
    Not that I don't believe you, but I want to investigate more.

    Leave a comment:


  • elaw
    replied
    Originally posted by Gabriel View Post
    In fact, you are wrong (almost).

    The plane was not in direct law, but in alternate law.
    Doh! Clearly I got a wrong impression somewhere along the line. Foot now lodged firmly in mouth...

    Leave a comment:


  • Evan
    replied
    Originally posted by Evan View Post
    Wrong. If you pull a traditional yoke back and hold [your intended target pitch] there, the nose does not go back down [before the stall].
    I forgot how exhaustively specific I have to be here.

    Leave a comment:


  • 3WE
    replied
    Originally posted by Evan View Post
    Wrong. If you pull a traditional yoke back and hold it there, the nose does not go back down.
    Very cool.

    Clearly you have never flown a traditional plane.

    The bold makes it so much better.

    Leave a comment:

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