Bonanza F33A "LDG GR POS" circuit breaker

Discussion in 'Pilot Training' started by RussR, Dec 3, 2019.

  1. RussR

    RussR Cleared for Takeoff

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    During an IPC yesterday with the owner of a 1993 F33A Bonanza, I surreptitiously pulled the "LDG GR POS" circuit breaker in an attempt to see if he would notice the lack of green lights as he lowered the gear at the FAF.

    In the attached picture, this is the 4th one on the top row, a 5A breaker.

    I thought "LDG GR POS" meant "Landing Gear Position (lights)" and expected the gear to go down but just the indicator lights to not work.

    Well, he did notice, because the gear did not go down either. Good on him for noticing that. So we still had an effective training event.

    If I had pulled the 30A "LDG GEAR" breaker (first one on bottom row), I would have expected this behavior. But not with the "LDR GR POS" breaker.

    So, one of two things - either I don't understand what "LDG GR POS" means here, or I don't understand how the 1993 F33A gear warning system works. Or, I guess, something's wrong with his airplane.

    I did look in the POH and it's not very detailed on this topic. I did not see a diagram of the electrical system in there either. Anybody have any knowledge about this and can steer me right?

    Thanks.

    [​IMG]
     
  2. MauleSkinner

    MauleSkinner Final Approach

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    I suspect that LDG GR POS is also the Landing Gear Control circuit, and LDG GR is just the motor...they haven’t put the full motor amperage through the gear switch for a few years now. ;)
     
    Last edited: Dec 3, 2019
  3. Bell206

    Bell206 Pattern Altitude

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  4. j1b3h0

    j1b3h0 Line Up and Wait

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    Clearly you’re not qualified to give dual in a Bonanza.
     
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  5. Checkout_my_Six

    Checkout_my_Six Final Approach

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    this is why CFI's shouldn't play with things.....o_O :D
     
    Last edited: Dec 5, 2019 at 1:47 PM
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  6. Kenny Phillips

    Kenny Phillips En-Route

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    Certainly I'd call that mislabeled.
     
  7. schmookeeg

    schmookeeg Cleared for Takeoff

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    In defense of OP, my BPPP CFI training and checkout did not cover that breaker either. You need to fish deep into the wiring diagrams to see all of the things that circuit feeds. It's a lot. :)
     
  8. Walboy

    Walboy Cleared for Takeoff

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    Interesting comments so far...

    Says a lot about @RussR that he can publicly post something like this to learn from it knowing he would likely take some heat. Not sure I would have the courage to do that.

    That's how the rest of us can learn, both systems and CFI technique.
     
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  9. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

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    I just think that label is a tad judgemental. Nothing wrong with Bonanza gear that I am aware of.
     
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  10. MauleSkinner

    MauleSkinner Final Approach

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    There’s not enough room on the panel to properly label it.

    You’d probably be amazed if you got into what all is on each circuit breaker relative to its labeling.
     
  11. MauleSkinner

    MauleSkinner Final Approach

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    :eek:

    :D
     
  12. Checkout_my_Six

    Checkout_my_Six Final Approach

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    so....did you figure out what "POS" means? :Do_O:confused:
     
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  13. RussR

    RussR Cleared for Takeoff

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    No smilie, but I considered that a joke anyway until subsequent posters made me wonder. So I laughed. But if I shouldn't have, no worries, let me know!

    Darn CFIs always "breaking" things. Starts with those instrument covers and goes from there! Pretty much a standard part of my FR (I know this was an IPC, but that doesn't make it off limits) to pull a gear CB in any retractable airplane. Seen too many people get complacent.

    I agree I don't remember that from the (excellent) BPPP training. I did all the training courses but never did take the official checkride. And it's not something that's in the POH anyway.

    Aw heck, I didn't see anything as "taking any heat" yet. And even if so, that's okay, to me part of being a good CFI isn't knowing everything, but being willing to learn. And a big part of learning is admitting you don't know something. But thanks!

    In the last 30 days I have either piloted or taught in 11 airplane types. I will admit it is sometimes hard to keep them straight:
    Piper PA-32
    Cessna 172
    Mooney M20J
    Cessna Citation Encore
    Cessna 340
    Piper PA-24
    Bonanza V35B
    Cessna 206
    Cessna Citation V
    Bonanza F33A
    Cessna 421C

    So I certainly can't be an expert on every CB on all of them.

    That was my first thought when I read it too! POS gear... Of course, there are other airplanes I would put that label on before the Bonanzas.
     
    Last edited: Dec 5, 2019 at 9:06 PM
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  14. woodchucker

    woodchucker Cleared for Takeoff

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    @RussR

    I’m just doing my IR now, but I think it’s best you learn all of the systems in your check aircraft before creating failures. That may necessitate a pre-flight with the owner/pilot where you go over all the systems. That’s what you are being paid for. Pulling breakers not knowing the outcome is poor behavior. And a safety of flight issue in my opinion.
     
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  15. Ryan F.

    Ryan F. Line Up and Wait

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    Absolutely. It's impossible to be a systems expert for every single training event when you fly many airplanes. Not a big deal. No 'heat' should be coming your way for this.

    I've certainly also been surprised by the behavior exhibited from the subject aircraft for a given simulated failure, usually avionics. It's hard to "fail" components anymore with CBs, especially with the integrated avionics suites we see out there nowadays -- as various components might 'ride' on one CB.

    For training, the art and science of how a CFI provides a rich learning experience for the client involves some experimentation at times.
     
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  16. RussR

    RussR Cleared for Takeoff

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    That's a fair viewpoint, but I have to disagree. Mostly it comes down to your last sentence.

    In most general aviation aircraft, which circuit breaker would cause a safety of flight issue if intentionally pulled for training on a clear VFR day? Would any of them actually cause a safety of flight issue? Remember, the airplane will fly just fine if you turn off the entire electrical system, including alternator and battery switches.

    However, please don't think I go around haphazardly pulling breakers. I pulled an appropriate one to create the training event desired. And it did create an effective training event. So as far as I am concerned, missed accomplished. The fact that it had additional effects created an enhanced training event, with no safety impacts. It is not unrealistic for that breaker to pop, and now he (and I) both know the effects.

    So for an IPC (or a FR), you recommend we conduct a pre-flight lesson on all the systems in the airplane, to include every circuit breaker, and system schematics that are not in the POH? I'd be happy to do that, but it would mean an all-day lesson instead of a couple-hour lesson. While certainly a great idea, few pilots would agree to pay for that.
     
    Last edited: Dec 6, 2019 at 7:46 AM
  17. Checkout_my_Six

    Checkout_my_Six Final Approach

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    I knew a bright older CFI that thought it would be brilliant to remove a landing gear indicator bulb in a 182RG.....it needed to be there....and the gear collapsed on landing. :confused:
     
    Last edited: Dec 6, 2019 at 8:19 AM
  18. tmyers

    tmyers En-Route

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    Rather than throwing stones at the OP, maybe this sharing of information would encourage you to to dig deeper into the aircraft you fly. Every aircraft I have flown has some small idiosyncrasy like this.
     
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  19. Ryan F.

    Ryan F. Line Up and Wait

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    I can stump anyone, even myself. Give me 10 minutes with the AFM and the TCDS and I can come up with a series of questions virtually no one can answer, not even long-time aircraft owners, without digging around. It's a rather pointless exercise, so I keep things realistic.

    Much better to just have a chat about "hey, why does this work this way?" and enjoy a nice collective learning moment. Thanks, Russ.
     
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