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Thread: Tiebreaker

  1. #1

    Tiebreaker

    I have dual adahrs 5600 screens and vizion 385 autopilot. Question has come up about tiebreaker in the instance of if it happens-- which adahrs to believe? Having no other steam gauges or real estate for them, would the vizion be a reliable wing leveler/ tiebreaker even in the case of pitot/static failure? I see Rob uses the D2 assuming for a tiebreaker?
    Dave Ford
    RV10

  2. #2
    Quote Originally Posted by rvdave View Post
    I have dual adahrs 5600 screens and vizion 385 autopilot. Question has come up about tiebreaker in the instance of if it happens-- which adahrs to believe? Having no other steam gauges or real estate for them, would the vizion be a reliable wing leveler/ tiebreaker even in the case of pitot/static failure? I see Rob uses the D2 assuming for a tiebreaker?

    You're making an apples to oranges comparison.

    What are you looking for a tiebreaker to do?

    Attitude
    Airspeed
    VSI
    Altitude

    You should have an alternate static source in your cabin. Stein sells a switch that's not too expensive. If you get a pitot blockage or open pitot line, I'm not sure how the Vizion will respond. It may depend on how your speed switch limits are set. It may refuse to engage depending on that limit. While the Vizion will level your wings from just about any attitude, I don't think it can hold an accurate altitude. It can hold it's current altitude. The problem is that you can only sync altimeters while on the ground. If you're flying cross country and the barometric pressure changes, how do you adjust the Vizion. By using MSL to set the altimeter instead of barometric pressure, you could be off several hundred feet. Don't get me wrong, it's a good AP (I have one too), just not something that I would use as a tie breaker.

    I currently have a Gemini PFD for a tie breaker, but am thinking about changing to a D2. I have yet to be able to get the Gemini pass the IFR certification, even after Trutrak recertifies the device.
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  3. #3
    Well actually wondering if a tiebreaker is really necessary with redundant adahrs and redundant display, unless both units get x'd--- wondering if that has ever happened? Also the Vizion should keep things level and course guidance I believe unless navigator fails also.
    Dave Ford
    RV10

  4. #4
    Quote Originally Posted by rvdave View Post
    Well actually wondering if a tiebreaker is really necessary with redundant adahrs and redundant display, unless both units get x'd--- wondering if that has ever happened? Also the Vizion should keep things level and course guidance I believe unless navigator fails also.
    Yes, it's necessary in my opinion. If you have two units and one goes bad, which one is working properly? Even if there is a red X on one, I want to validate that the correct one was marked as not usable.

    Yes, the Vizion can level your wings.

    If you're in IMC, I certainly would like to know which attitude instrument is correct. The only way to guarantee that is with three devices, which one is a tiebreaker. Preferably, the third unit is running a different code base than the primaries. You wouldn't want a common software bug to take all three out at the same time.
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  5. #5
    My thinking is that with the Vizion engaged in level flight would indicate if an adahrs were indicating improper attitude or bank since it operates independent, wouldn't that be the tiebreaker? Although it wouldn't be instant recognition as if the ap was not being used at the time. I may be wrong since I'm not yet flying and haven't had real time exploration and experience with the interactions.
    Last edited by rvdave; 05-17-2017 at 06:06 AM.
    Dave Ford
    RV10

  6. #6
    Quote Originally Posted by rvdave View Post
    My thinking is that with the Vizion engaged in level flight would indicate if an adahrs were indicating improper attitude or bank since it operates independent, wouldn't that be the tiebreaker? Although it wouldn't be instant recognition as if the ap was not being used at the time. I may be wrong since I'm not yet flying and haven't had real time exploration and experience with the interactions.
    My assumption is that while in IMC, do I want to trust my life to the capabilities of the Vizion being able to level the wings? It's likely to be able to do that. If you've never been in quick, severe turns or movement in IMC, it can be quite disorientating. Since it's my life and potentially my family's, I want more tools and capabilities than less. Also, attitude is a function of airspeed. Am I at the top or bottom of the airspeed arc? I want to be manually able to confirm that myself.
    Bob Leffler
    N410BL - RV10 - Flying
    http://mykitlog.com/rleffler

  7. #7
    Member
    Join Date
    May 2016
    Location
    Largo, FL, Based at Clearwater Airpark KCLW
    Posts
    31
    Bob, I will be installing a 5600T in my RV-6A, but am keeping my Dynon D10A --- I have the Vizion 385, currently hooked to the Garmin 650. However, my tiebreakers will always be the Dynon D2 and the iFly 740, which will give me GPS altitude and groundspeed (close enough for emergencies.)

    Ron

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