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Thread: Pitot Tube Failure

  1. #61
    Senior Member Evan's Avatar
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    Quote Originally Posted by ATLcrew View Post
    Affirmative. Even if we're in a gentle descent, that's still FDnH.
    Can we all agree that the definition of "fat dumb and happy" is "matching and mashing to put the nose back where is was" whilst contending with turbulence and roll in manual flight after a sudden loss of autoflight, the loss of airspeeds and an urgently developing failure cascade?

  2. #62
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    Can we all agree that the definition of "fat dumb and happy" is "matching and mashing to put the nose back where is was" whilst contending with turbulence and roll in manual flight after a sudden loss of autoflight, the loss of airspeeds and an urgently developing failure cascade?
    At least in the short term, sure.

    How sustainable is 5deg and CLB in the long term starting from 35000ft ISA+20?

    A simple calculation tells me that they would have had an initial climb of 2800 fpm. The speed was going to go down.

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  3. #63
    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    At least in the short term, sure.

    How sustainable is 5deg and CLB in the long term starting from 35000ft ISA+20?

    A simple calculation tells me that they would have had an initial climb of 2800 fpm. The speed was going to go down.
    5 deg and climb is the memorized part, the stabilizing part, which only needs to be sustained for a brief period of time while the more appropriate values are obtained from the QRH. But you know this...
    Also, the QRH procedure includes getting the autothrust out of thrust lock and actually setting it at full climb power. And actually turning off the flight directors that were intermittantly giving the pilots very bad direction.

    Seriously, there was nothing fat dumb or happy about what AF447 fell into and the situation was absolutely impacting the safe conduct of the flight. There was no justification there for skipping the memory items and going to an ADR Check Procedure. I mean, that's absurd. Again, where is this resistance to a safe, practiced and memorized procedure coming from?

  4. #64
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    Quote Originally Posted by Evan View Post
    Seriously, there was nothing fat dumb or happy about what AF447 fell into and the situation was absolutely impacting the safe conduct of the flight. There was no justification there for skipping the memory items and going to an ADR Check Procedure. I mean, that's absurd. Again, where is this resistance to a safe, practiced and memorized procedure coming from?
    In this case it's coming from Airbus. If you disagree, that's certainly your business. "Safety of flight is impacted" in this case means "are you fixin' to hit something?". If the answer is no, you don't do the memory item. The "context" of this memory item is to get you somewhere where you can "level off and troubleshoot" (it says as much). If that's absurd to you, once again, that's your business. Now, there was certainly no justification for what they DID do, but that does not make the memory item applicable.

  5. #65
    Senior Member 3WE's Avatar
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    Quote Originally Posted by ATLcrew View Post
    ...Negative...Affirmative...Negative...Affirmative...
    https://www.youtube.com/watch?v=aTRSmjUfYrs

    Especially, "LOUD NOISES"
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  6. #66
    Senior Member Evan's Avatar
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    Quote Originally Posted by ATLcrew View Post
    In this case it's coming from Airbus. If you disagree, that's certainly your business. "Safety of flight is impacted" in this case means "are you fixin' to hit something?". If the answer is no, you don't do the memory item. The "context" of this memory item is to get you somewhere where you can "level off and troubleshoot" (it says as much). If that's absurd to you, once again, that's your business. Now, there was certainly no justification for what they DID do, but that does not make the memory item applicable.
    I think you are misinterpreting this. Can you provide us with your companies' actual training definition of 'safety of the flight is impacted'?

    If it said 'safety of the flight path is impacted' then I'd understand (though I would not understand the logic, since leveling off is probably a good way to hit something). But to my untrained mind, 'safety of the flight is impacted' means a lot more than flight path.

    And the memory procedure still includes 'Above THRUST RED ALT and Above FL100'. So what are you fixin' to hit there? A mountain? If so, why would you want to level off? If anything, 'fixin' to hit something' is only a good reason NOT to use the memory procedure.

    What am I missing?

  7. #67
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Evan View Post
    1) A good way to hit something
    2) THRUST RED ALT and Above FL100'.
    3) What am I missing?
    The answer to "3" is that because you are so focused on acronyms ("2"), you cannot comprehend "1".

    If the plane is flying along perfectly well, don't phugoid it up by pulling the potentially WRONG memory item out of your overloaded head.

    Fly on, and CAREFULLY diagnose what's going on, talk, review checklists, consult the Book of Acronyms, recall 172 fundamentals.

    The tough thing is that it prolly would have worked (including totally cowboy improvising on familiar P,P&P + 172 fundamentals- even though that shouldn't be the "choice" per se.)
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  8. #68
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    5 deg and climb is the memorized part, the stabilizing part, which only needs to be sustained for a brief period of time while the more appropriate values are obtained from the QRH. But you know this...
    The same is true for the "don't touch anything" procedure. Note that you should transition from the 5 deg / CLB to the "level off" when you are at or above MSA or Circuit Altitude. What if you are already leveled off above the MSA?

    Also, the QRH procedure includes getting the autothrust out of thrust lock[/quote]
    Does it?
    http://flightacademy.info/wp-content...-procedure.png

    And actually turning off the flight directors that were intermittantly giving the pilots very bad direction.
    Yep, you have to do so even if you don't do the memory items.
    It is the first items under "To level off for torubleshooting", which is the first thing you in the QRH if you don;t do the memory items.

    Seriously, there was nothing fat dumb or happy about what AF447 fell into and the situation was absolutely impacting the safe conduct of the flight.
    How so?

    "UAS, just keep it there, UAS QRH items please, skip memory items, AP/FD/AT off, for our weight and altitude keep this thrust and pitch (which, go figure, would have been 2.5 deg and 79% N1 initial target), flight technique: adjust pitch to keep the desired flightpath, if pitch increase increase thrust, if pitch decreases decrease thrust, when flight path is stabilized... (troubleshooting starts)"

    ALL THAT IS IN THE QRH AND YOU HAVE TO DO IT WHETHER YOU JUDGE THE SAFE CONDUCT OF THE FLIGHT AND DO THE MEMORY ITEMS OR THAT IT IS NOT AFFECTED AND SKIP THE MEMORY ITEMS.

    Again, if you skip the memory items the first thing in the QRH is the level-off pitch/thrust and the next thing is the flight technique to stabilize speed.
    So the only difference is if you keep it stable where it was until you get the QRH out or if you go memory items in the meantime.

    There was no justification there for skipping the memory items and going to an ADR Check Procedure. I mean, that's absurd. Again, where is this resistance to a safe, practiced and memorized procedure coming from?
    And it looks to me that you are all for following the procedure until it doesn't feet your mental picture.

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  9. #69
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    If it said 'safety of the flight path is impacted' then I'd understand (though I would not understand the logic, since leveling off is probably a good way to hit something). But to my untrained mind, 'safety of the flight is impacted' means a lot more than flight path.
    You are misunderstanding it. The memory items are there to provide a reasonable CLIMB until above the MSA, and THEN LEVEL OFF using the specific QRH table. It is written there verbatim.

    And the memory procedure still includes 'Above THRUST RED ALT and Above FL100'. So what are you fixin' to hit there? A mountain? If so, why would you want to level off? If anything, 'fixin' to hit something' is only a good reason NOT to use the memory procedure.

    What am I missing?
    A LOT!!!

    There are plenty of things that you can hit at FL100 which is MSL, including the runway.
    And this is to CLIMB, not to LEVEL OFF. You are not supposed to level off until AFTER REACHING THE MSA, which where you will not hit anything. Level off if the first action AFTER (and out of) the memory items.

    Did you note that there is no "above FL320" (or anything after FL100) for the memory items but yes for the level off table?

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  10. #70
    Member ATLcrew's Avatar
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    Quote Originally Posted by Evan View Post
    I think you are misinterpreting this.
    I think you're reaching.

  11. #71
    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    And it looks to me that you are all for following the procedure until it doesn't feet your mental picture.
    OK, let's examine at my mental picture. The picture concerns the very first, immediate pilot actions while gathering situational awareness, from the moment ADR DISAGREE and unreliable speeds is acknowledged. I consider this to be the critical danger zone.

    What are the GOAL's here?

    1. To avoid structural damage or loss of control from overspeed.
    2. To avoid stall from underspeed.
    3. To avoid significant departure from flight level in RVSM airspace.
    4. To avoid an in-flight upset that might lead to a loss of control.

    I consider #4 to be the most immediate goal.

    What are the options?

    1. Maintain current (stable) flight path.
    2. Apply the memorized (and practiced) procedure.
    3. Improvise new pitch and power settings.

    Option #1: Certainly this will work if there is nothing to upset the flight path AND the flight path is, in fact stable to begin with (AF447's was not).
    Option #2: Certainly this will work in any case unless it is executed incorrectly (failure of memory, although "5 and Climb" is pretty hard to forget).
    Option #3: Certainly this will work if the pilot has practiced airmanship skills at altitude, clear situational awareness and sound judgment despite the disorienting nature of startle and stress (AF447 showed us how unreasonable that is).

    So which is the most uncertain? Definitely #3 (the one taken by AF447). That leaves two options.

    Option #1 minimizes the possibilty of upset, since there is no significant deviation from the current flight path, but it is conditional. It relies on sound situational awareness in a very complex aircraft with stealth factors involved. As a first action, with no procedural guidance, there is no immediate provision to assure these factors have been addressed (AF447 did not immediately address these factors, nor did at least five of the eleven documented cases of high altitude UAS involving loss of autoflight listed in the AF447 final report).

    Option #2 carries only a slightly higher risk of upset because it does require a deviation from the flight path but it is still very simple to execute and, unless executed incorrectly, is unconditionally effective.

    If (and only if) Option #1 is indeed stable to begin with and is followed immediately by the UAS procedure and level-off pitch and power tables (assuming above MSA), I don't have a problem with that.

    I prefer Option #2 because it establishes a known stable flight path and it integrates the stealth factor avoidance items, specifically setting power correctly and shutting off the FD's and is not affected by inaccurate altimeter reading.

    Option #3 is, sooner or later, a recipe for disaster (as AF447 has shown us). This cannot be the chosen option (though it most often is).

    A few things I can't parse with logic:

    Thing #1) Page 17 of the Unreliable Speed Airbus slideshow we are looking at. The new 'combined' procedure goes like this:

    1. Memory Items or Not.
    2. Level off (for troubleshooting) procedure using QRH pitch and power tables.
    3. Troubleshooting (UAS/ADR Disagree).
    4. Pitch and power tables.

    Aren't we doing something twice there, and if so, why?

    Thing #2) In level flight, if the safety of the flight is impacted because you are "fixin' to hit something", why would maintaining the current flight path be preferred over the Memory Items?

    Thing #3) What is actually meant by "does not affect the safe conduct of the flight" (the actual wording used by Airbus on the written UAS procedure instructing us to skip the memory items and go directly to the ADR disagree procedure).

  12. #72
    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    There are plenty of things that you can hit at FL100 which is MSL, including the runway.
    Ok, so then I just need a list of runways that are above THRUST RED ALT (the word following that is 'and', not 'or').

  13. #73
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    Ok, so then I just need a list of runways that are above THRUST RED ALT (the word following that is 'and', not 'or').
    Ok, lt me correct my previous statement.

    With runways at elevations above or slightly below 10000ft, there may be many terrain features and other stuff that can be hit below thrust reduction altitude which is typically not below 1500 ft above the runway elevation. You are intentionally splitting hairs (no complaint, I am an expert in that) and avoiding more important stuff (complaint here) like the fact that the memory items pitch and thrust setting end when you reach MSA or circuit altitude and then you need to go to the QRH tables to level off and apply the flight technique to stabilize speed (described after the tables).

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  14. #74
    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    OK, let's examine at my mental picture. The picture concerns the very first, immediate pilot actions while gathering situational awareness, from the moment ADR DISAGREE and unreliable speeds is acknowledged. I consider this to be the critical danger zone.

    What are the GOAL's here?

    1. To avoid structural damage or loss of control from overspeed.
    2. To avoid stall from underspeed.
    3. To avoid significant departure from flight level in RVSM airspace.
    4. To avoid an in-flight upset that might lead to a loss of control.

    I consider #4 to be the most immediate goal.

    What are the options?

    1. Maintain current (stable) flight path.
    2. Apply the memorized (and practiced) procedure.

    Option #1: Certainly this will work if there is nothing to upset the flight path AND the flight path is, in fact stable to begin with (AF447's was not).
    Option #2: Certainly this will work in any case unless it is executed incorrectly (failure of memory, although "5 and Climb" is pretty hard to forget).

    Option #1 minimizes the possibilty of upset, since there is no significant deviation from the current flight path, but it is conditional. It relies on sound situational awareness in a very complex aircraft with stealth factors involved. As a first action, with no procedural guidance, there is no immediate provision to assure these factors have been addressed (AF447 did not immediately address these factors, nor did at least five of the eleven documented cases of high altitude UAS involving loss of autoflight listed in the AF447 final report).

    Option #2 carries only a slightly higher risk of upset because it does require a deviation from the flight path but it is still very simple to execute and, unless executed incorrectly, is unconditionally effective.

    If (and only if) Option #1 is indeed stable to begin with and is followed immediately by the UAS procedure and level-off pitch and power tables (assuming above MSA), I don't have a problem with that.

    I prefer Option #2 because it establishes a known stable flight path and it integrates the stealth factor avoidance items, specifically setting power correctly and shutting off the FD's and is not affected by inaccurate altimeter reading.
    Read carefully what you've just written. Are you being fair? Because I am smelling confirmation bias.
    If you after careful reflection you still don't agree, we can discuss.

    A few things I can't parse with logic:

    Thing #1) Page 17 of the Unreliable Speed Airbus slideshow we are looking at. The new 'combined' procedure goes like this:

    1. Memory Items or Not.
    2. Level off (for troubleshooting) procedure using QRH pitch and power tables.
    3. Troubleshooting (UAS/ADR Disagree).
    4. Pitch and power tables.

    Aren't we doing something twice there, and if so, why?
    Because you still got the wrong picture. You've taken off in IMC, are climbing out and you fly through a flock of birds that damage your pitot tubes.
    1) Don't crash against the ground. You don't see what's around you. Are you below a safe altitude? Memory items to ensure a reasonable climb.
    2) When you reach a comfortable location and altitude to troubleshoot, level off using the QRH tables.
    3) Stabilize the speed using the QRH flight technique.
    4) Troubleshoot.
    5) Still no valid speed insdication? Ok, it seems that you will have to complete the flight with no speeds. What's next? You can't return to land in IMC, you need VMC at least for the landing. There is a suitable airpot over there across the mountain range but you also need to save fuel. So you will need to a) Climb to the desired and safe cruise altitude (table), b) level off at the desired cruise altitude and c) descend when approaching the diversion airport.

    Thing #2) In level flight, if the safety of the flight is impacted because you are "fixin' to hit something", why would maintaining the current flight path be preferred over the Memory Items?
    No, if you are fixin' to hit something, use the memory items to climb. That is what they are designed for. Now, if you are NOT fixin' to hit something, well, read what you've put above and see if the comparative evaluation of options #1 and #2 is fair.


    Thing #3) What is actually meant by "does not affect the safe conduct of the flight" (the actual wording used by Airbus on the written UAS procedure instructing us to skip the memory items and go directly to the ADR disagree procedure).
    I think that ATL answered that already . A million times.

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  15. #75
    Senior Member TeeVee's Avatar
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    this brings new meaning to the word "stubborn"

  16. #76
    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    Read carefully what you've just written. Are you being fair? Because I am smelling confirmation bias.
    If you after careful reflection you still don't agree, we can discuss.

    Because you still got the wrong picture. You've taken off in IMC, are climbing out and you fly through a flock of birds that damage your pitot tubes.
    1) Don't crash against the ground. You don't see what's around you. Are you below a safe altitude? Memory items to ensure a reasonable climb.
    2) When you reach a comfortable location and altitude to troubleshoot, level off using the QRH tables.
    3) Stabilize the speed using the QRH flight technique.
    4) Troubleshoot.
    5) Still no valid speed insdication? Ok, it seems that you will have to complete the flight with no speeds. What's next? You can't return to land in IMC, you need VMC at least for the landing. There is a suitable airpot over there across the mountain range but you also need to save fuel. So you will need to a) Climb to the desired and safe cruise altitude (table), b) level off at the desired cruise altitude and c) descend when approaching the diversion airport.
    Ok, I finally located the FULL QRH procedure and I see what you are saying. The Memory Item values are for climb. The level-off value for the A330 above 190t is 3 deg / 94.3 N1. I'm not certain what the Memory Procedure yields but it is certainly a climb at 5 deg / CL based on the fact that, when the crew advanced the TL's to the CL detent, the N1 increased to 104% (I expect 5 deg and 104% would produce a moderate climb at that weight/altitude). On the fourth page of the procedure are further tables for pitch/power in CLIMB, CRUISE, DESCENT and APPROACH if needed.

    I think one thing that is confusing me is that these procedures were never written or intended for the sudden and total loss of airspeed data (i.e. ice ingestion) and autoflight in the cruise-level phase of flight, as the phenomena of supercooled water and high elevation of ice crystals was not well-understood and therefore that was previously not considered a plausible (or even possible) scenario. So memory (instant recall) items do not exist for this scenario.

    So, the memory procedures, which yield a climbing flight path, do not apply to cruise-level flight unless "the safe conduct of the flight is affected" (I assume this means wherever a climb is necessary), but the QRH procedure still calls for, as a first action after shutting down the AT and FD's, factory-engineered pitch and power settings. As I said in my previous post, I'm fine with that. My concern has always been that pilots avoid improvising on pitch and power, even if they consider it "known" to them, and that the initial commands departing from the current flight path are guided by these reference values.

    There are problems with that though. For one thing, the total loss of speeds in high-altitude turbulence results in an immediate loss of autoflight and need for manual intervention before the QRH values can be obtained. The pitch attitude prior to the disconnect could be quickly lost in that choppy, rolling transition. Therefore, it seems logical that a similar pair of broad, cruise-level-flight pitch/power targets should also be provided as a Memory Item for all weight categories above and below FL250, just to stabilize within the safe envelope for a minute or so. Again, I agree that a provisional autoflight mode is the most optimum idea and I don't see any reason that it can't, or shouldn't, be implemented.

    In any case, I remain steadfastly opposed to the idea of improvisation here. That has to stop. WIth no speed reference, misleading altitude and vertical speed references and the FD in self-destruct mode and the autothrottle in stealth mode, the procedures and engineering-derived pitch and power targets must be expediently followed.

  17. #77
    Senior Member 3WE's Avatar
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    Quote Originally Posted by Evan View Post
    I remain steadfastly opposed to the idea of improvisation here.
    I steadfastly support the idea that when you are overwhelmed and don't have a clue what to do, that it is OK to default to broadly applicable fundamentals unless you were trained that this was some phugoided system where the fundamental rule will result in the wrong thing. (I'm sure such situations exist and am sure there is training to be sure NOT to do it the 172 way).

    Defaulting to fundamentals is:

    1. Simpler when you are totally clueless.

    2. It's pretty damn close to the exact procedure ATL prescribed of: Fly on, assure you are stable and then start high-quality trouble shooting.

    3. It would have worked that night (I double steadfastly proclaim).

    I very much agree that total stupid improvisation which goes almost totally against basic, broadly-applicable fundamentals is wrong (unless there are specific reasons and training for a type-specific system that works other than basic aerodynamic rules).
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  18. #78
    Senior Member 3WE's Avatar
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    Quote Originally Posted by TeeVee View Post
    this brings new meaning to the word "stubborn"
    LOUD NOISES!!!!!

    https://www.youtube.com/watch?v=aTRSmjUfYrs
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

  19. #79
    Senior Member Evan's Avatar
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    Quote Originally Posted by 3WE View Post
    I very much agree that total stupid improvisation which goes almost totally against basic 172 fundamentals is wrong (unless there are specific reasons and training for a type-specific system that works other than basic aerodynamic rules).
    But how do you know which you are going to get 3WE, the intact fundamentals of the broken ones? Remember, human factors are rather awesome. Bonin was an experienced glider pilot. He had a solid understanding of fundamentals, in his normal, intact brain. Pilots need a reference in this dangerous state of confusion. And passenger's need to be protected from them. And automation could do that here.

  20. #80
    Senior Member TeeVee's Avatar
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    Quote Originally Posted by Evan View Post
    And automation could do that here.
    Click image for larger version. 

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