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Thread: Pilots Monkeying with CB's

  1. #1
    Senior Member Evan's Avatar
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    Default Pilots Monkeying with CB's

    Do we have to start locking these things away from certain third world aviators? First Air Asia and now this from the Trigana AT42 crash:

    These experiences led to the pilot behaviour of pulling the EGPWS circuit breaker to eliminate nuisance of EGPWS warning.

    The management had identified some pilots including the accident pilot with behaviour of pulling EGPWS CB.

    Yeah, that's right, 'pilots', pural. Culture.

    I get the very strong impression that basic airmanship alone isn't cutting it anymore. Pilots need to be educated on the essential nature of these systems and that, no matter how much of a "nuisance" they are, you can't just pull them.

    Ironically, when LOT flt 16 could have been spared the indignity of a belly landing with a simple CB reset, nobody thought of this...

    More CB knowledge up there please.

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    Senior Member Gabriel's Avatar
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    Quote Originally Posted by Evan View Post
    Ironically, when LOT flt 16 could have been spared the indignity of a belly landing with a simple CB reset, nobody thought of this...
    Because that required PUSHING a CB, not PULLING one.

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    Senior Member Evan's Avatar
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    Quote Originally Posted by Gabriel View Post
    Because that required PUSHING a CB, not PULLING one.
    This is what we're dealing with. Yes, resetting requires pushing. I can't recall if there was a maintenance collar on that breaker.

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    Senior Member 3WE's Avatar
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    Is this in reference to the January edition of Flying Magazine where a single engine airplane was spit out of a CB in pieces while a nearby Cessna 402 reported no unusual turbulence?
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    Senior Member 3WE's Avatar
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    Quote Originally Posted by Evan View Post
    More CB knowledge up there please.
    I don't think it's that simple. This is more like one the classic case of turning off the good engine. Seems like working with CB's is a very normal part of aviation and resetting all of the scientifically engineered electronic safety double checker systems...then, throw in the simple, old fashioned brain fart.

    One of my many favorite J-31 memories was the pilots trying to reset the fuel-used display. Punched the reset buttons about 10 times...and finally it took...so that is how we fix glitch, oh, yeah, real high tech!
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    Senior Member Evan's Avatar
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    Quote Originally Posted by 3WE View Post
    One of my many favorite J-31 memories was the pilots trying to reset the fuel-used display. Punched the reset buttons about 10 times...and finally it took...so that is how we fix glitch, oh, yeah, real high tech!
    And tragically, this is the DIY, improv mentality that is sometimes imported into commercial aviation by pilots lacking training and technical understanding.

    Anyway, here we have a case of something that is not in need of resetting, that is operating perfectly, and providing protection against CFIT, but the crew finds it annoying, despite currently skimming above dangerous mountainous terrain.

    The captain (60, ATPL, 25,287 hours total, 7,341 hours on type) was assisted by a first officer (44, CPL, 3,818 hours total, 2,640 hours on type).

    When it comes to bad habits, the more hours clocked, the more dangerous the pilot.

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    Senior Member Gabriel's Avatar
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    Quote Originally Posted by 3WE View Post
    Is this in reference to the January edition of Flying Magazine where a single engine airplane was spit out of a CB in pieces while a nearby Cessna 402 reported no unusual turbulence?
    Ha! It took me a while. Would have never gotten it if it wasn't for the other thread there.

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    Quote Originally Posted by Evan View Post
    When it comes to bad habits, the more hours clocked, the more dangerous the pilot.
    Care to back this up by fact? At my old company by the way, you were allowed one reset attempt of a CB.

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    Quote Originally Posted by 3WE View Post
    Is this in reference to the January edition of Flying Magazine where a single engine airplane was spit out of a CB in pieces while a nearby Cessna 402 reported no unusual turbulence?
    Contact Breakers, not Cumulo Nimbus !! .....or have you trapped me into biting ?

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    Senior Member Evan's Avatar
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    Quote Originally Posted by BoeingBobby View Post
    Care to back this up by fact? At my old company by the way, you were allowed one reset attempt of a CB.
    A pull, a cycle or a reset? Which ones and why and in what sequence? Certainly there are CB's that can be reset in flight. Fewer thay can be safely pulled or cycled. Very few (none, I would argue) that can be safely pulled without understanding the systems and circuits you are messing with and the cascade of consequences that might result. Wouldn't you agree?

    What I'm talking about here are very systems-dumb pilots who are using CB's as a routine control to defeat nuisances, like a EGPWS that is just doing what it is designed to do or a yaw damper that is acting up. There IS a GROUND procedure to reset the yaw damper on the A320 by cycling the FAC circuit breakers (the procedure is actually to use the pushbutton first and to go to CB's only if the pushbutton doesn't solve the problem). The reset time is 90 seconds and it must be done with the engines off and the hydraulics depressurized. Some daft Air Asia pilot (with plenty of flight hours) observes this is thinks "aha, I can do that!" Right. So they pulled one - nothing - then reset that without waiting 90 secs and pulled the other. Bang! Now they have no FAC function, no speed protections, no normal law and no autopilot. And after that, apparently no situational awareness and thus no airmanship. And now they no longer fly or walk or breath or do stupid things with CB's.

    Yet this is proven to be a culturally ingrained practice at some airlines.

    Now we've got an airline where some of its pilots are pulling the EGPWS circuits while skimming over mountaintops in IMC. What could go wrong? Well, the charts could be inaccurate, the MSA too low. The altimeters off. And you just shut down your primary line-of-defense—excuse me, OUR primary line-of-defense—because it was annoying you.

    And then we have a LOT 767 where the alternate gear extension isn't responding and nobody thinks to check the uplock CB! Which would have been quite obviously open. It makes me wonder how much pilot "need-to-know" is going on here, how much flight engineering isn't be taught anymore.

    Tell us, BB, at what point is it appropriate to pull a CB in flight?

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    Senior Member Gabriel's Avatar
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    Quote Originally Posted by brianw999 View Post
    Contact Breakers, not Cumulo Nimbus !! .....or have you trapped me into biting ?

    Happy new year to all my non picture uploading clients !
    Yes, it is CIRCUIT breaker.
    Yes, you bit into the joke. 3WE knew exactly what Evan was talking about.
    Yes, happy new year for you too

    --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
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    Senior Member 3WE's Avatar
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    Quote Originally Posted by brianw999 View Post
    Contact Breakers, not Cumulo Nimbus !! .....or have you trapped me into biting ?

    Happy new year to all my non picture uploading clients !
    Yes. We are too in love with our acronyms, and there are risks when you monkey with CBs. Happy parlour talk new year.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    Senior Member 3WE's Avatar
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    Quote Originally Posted by Gabriel View Post
    Ha! It took me a while. Would have never gotten it if it wasn't for the other thread there.
    You could have referenced the said edition. It was a good read. Not_simple cowboy idiocy, but gray areas.
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    Quote Originally Posted by Evan View Post
    Tell us, BB, at what point is it appropriate to pull a CB in flight?

    Follow the checklist, then use your Captain's authority to do what ever the hell you have to do to get her on the ground!

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    Quote Originally Posted by BoeingBobby View Post
    Follow the checklist, then use your Captain's authority to do what ever the hell you have to do to get her on the ground!
    I have no problem with that. What I'm talking about is monkeying with CB's that have nothing to do with checklists or imminent danger.

    And a pandemic lack of vital knowledge up there.

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    Quote Originally Posted by Evan View Post
    I have no problem with that. What I'm talking about is monkeying with CB's that have nothing to do with checklists or imminent danger.

    And a pandemic lack of vital knowledge up there.
    You can thank ALPA and United airlines for that! No more flight engineers! Remember that most of the engineers started as mechanics. One of the things I missed most when we parked our 200's and I went over to the "glass" airplane, was looking over my right shoulder and asking the engineer, "what's going on" or "what have we got"?

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    Quote Originally Posted by BoeingBobby
    You can thank ALPA and United airlines for that! No more flight engineers! Remember that most of the engineers started as mechanics. One of the things I missed most when we parked out 200's and I went over to the "glass" airplane, was looking over my right shoulder and asking the engineer, "what's going on" or "what have we got"?
    I've considered that. It must have been an uneasy feeling to lose the systems guy on a such a complex airplane. ECAM/EICAS was supposed to make up for this but, as we have seen, there are situations for which no written procedure exists and that now requires pilots to have more flight-engineering awareness than they used to. Facing a pilot shortage and an ever-growing demand, airlines are going to be under pressure to get new crews in the cockpit as soon as possible, without taking the extra time to fully address the flight-engineering role (and LIMITATIONS of that role) before they get there. But the other threat as I see it are well-seasoned pilots who know the aircraft very well in general and believe they can confidently improvise with the electrical systems as if they really were flight engineers. There are plenty of steath factors lurking there on complex modern jets. It needs to be impressed upon ALL pilots, including the old hands, that CB's are there to be used in flight as last resorts with extreme caution.

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    If pilots are pulling CB's because of nuisance, I think there is a problem with the alerting system, and this isn't really a problem with the pilots. Although I'm dealing with computer systems that run 7/24/365, I am really draconian about nuisance alerts. Either fix them (no false alarms) or shut them off. Whether we like it or not, a nuisance alert almost always results in people being trained to ignore it, or even worse, start ignoring all alerts or responding to them slower because they assume at first it is false.

    IMO, I think this is an alerting defect.

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    Senior Member Evan's Avatar
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    Quote Originally Posted by Schwartz View Post
    .

    IMO, I think this is an alerting defect.
    It isn't. The terrain is there. They are flying an approach over mountainous terrain. EGPWS is predictive, so it is looking at closure rates towards terrain ahead as well as below. It doesn't like mountainous terrain, but that is a good thing, as mountaintops tend to be unforgiving to airplanes. There are multiple warning envelopes however (sink rate, closure rate, below glideslope, below miminums, gear not down, etc.). What they were probably getting here were terrain closure alerts for terrain AHEAD and sporadically below due to these mountaintops. But if the aircraft is in landing configuration, that warning envelope is only about 500ft vertical and 2200fpm closure rate. It's not hard to stay out of that envelope and if you are within it, especially in IMC, YOU SHOULD be getting distracted by EGPWS. Now, if you don't want to have full landing flaps out at that point, the envelope increases, but you can inhibit those warnings with a guarded switch on the captain-side panel, as long as the gear is out. If you don't bother to do this, and you are clean or in reduced flap settings, that alert envelope is going to extend up to about 1,700ft vertical depending on your closure rate. That could get bothersome.

    Now, look at the approach path for this accident. It's a non-standard approach in IMC over mountainous terrain. Under those circumstance you must live with the minor distraction of an essential line of defense. It also appears that the MSA on the charts is too low. This can happen in remote places. That's why you have to have to have that line of defense.

    The first chart below shows the envelope out of landing configuration. If you have a 4000fpm closure rate on a mountain ahead, you can get a TERRAIN TERRAIN warning at 1500ft RA and the repeated PULL UP warnings.

    The second chart shows the envelope in landing configuration (or in guarced-switch override). There's a lot more room there before the system starts to annoy you.

    Bottom line: if you know how the system works, you can avoid most of these nuisance alerts by maintaining a reasonable separation from terrain and configuring everything appropriately. And, under these conditions, if you have to put up with a few nuisance alerts, live with it. It sure beats die without it.
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    Quote Originally Posted by Evan View Post
    It isn't. The terrain is there. They are flying an approach over mountainous terrain. EGPWS is predictive, so it is looking at closure rates towards terrain ahead as well as below. It doesn't like mountainous terrain, but that is a good thing, as mountaintops tend to be unforgiving to airplanes. There are multiple warning envelopes however (sink rate, closure rate, below glideslope, below miminums, gear not down, etc.). What they were probably getting here were terrain closure alerts for terrain AHEAD and sporadically below due to these mountaintops. But if the aircraft is in landing configuration, that warning envelope is only about 500ft vertical and 2200fpm closure rate. It's not hard to stay out of that envelope and if you are within it, especially in IMC, YOU SHOULD be getting distracted by EGPWS. Now, if you don't want to have full landing flaps out at that point, the envelope increases, but you can inhibit those warnings with a guarded switch on the captain-side panel, as long as the gear is out. If you don't bother to do this, and you are clean or in reduced flap settings, that alert envelope is going to extend up to about 1,700ft vertical depending on your closure rate. That could get bothersome.

    Now, look at the approach path for this accident. It's a non-standard approach in IMC over mountainous terrain. Under those circumstance you must live with the minor distraction of an essential line of defense. It also appears that the MSA on the charts is too low. This can happen in remote places. That's why you have to have to have that line of defense.

    The first chart below shows the envelope out of landing configuration. If you have a 4000fpm closure rate on a mountain ahead, you can get a TERRAIN TERRAIN warning at 1500ft RA and the repeated PULL UP warnings.

    The second chart shows the envelope in landing configuration. There's a lot more room there before the system starts to annoy you.

    Bottom line: if you know how the system works, you can avoid most of these nuisance alerts by maintaining a reasonable separation from terrain and configuring everything appropriately. And, under these conditions, if you have to put up with a few nuisance alerts, live with it. It sure beats die without it.
    I can show you that becoming aclimatised to nuisance alerts is as fatal as not having them. In some cases worse. If you train yourself not to react to an nuisance alert, you might ignore a similar alert at first that turns out to be fatal. Ignoring "a few nuisance" alerts can become just as deadly.

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