Garmin G5 HSI troubleshoting challenge

Discussion in 'Avionics and Upgrades' started by Baron62, Feb 13, 2018.

  1. Baron62

    Baron62 Pre-takeoff checklist

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    My airplane just came out of an avionics upgrade that includes a G5 HSI with GMU-11, GAD-29B plus a GTN 650 and unfortunately the G5 heading bug does not drive the Century 21 autopilot correctly. In GPSS mode the AP follows the DTK nicely. I will be calling the shop in the morning to have them fix it, but I was wondering if you guys had any ideas? I will also be checking the 650 and G5 config settings.

    When in HDG bug mode:
    1. moving the heading bug left or right of the mag heading does not turn the yoke unless you go left of right of a totally different arbitrary bearing. (HSI heading does match wet compass)
    2. the arbitrary bearing changes when I activate different flight plans/DTKs (in HDG bug mode!, not GPSS)

    There really isn't a lot of wiring as shown below.

    upload_2018-2-13_20-10-57.png
     
    Last edited: Feb 13, 2018
  2. Baron62

    Baron62 Pre-takeoff checklist

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  3. Axtel4

    Axtel4 Pre-takeoff checklist

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    Does the "arbitrary heading" align with the course pointer?
     
  4. WannFly

    WannFly Pattern Altitude PoA Supporter

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    GMU 11 not calibrated right?


    Sent from my iPhone using Tapatalk
     
  5. Baron62

    Baron62 Pre-takeoff checklist

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    No, it does not align with the course pointer. I am wondering if the DG Select ground on the Century 21 AP CD185 pin 17 needs to be removed becuse I am going from a DG to an HSI.
     
  6. Baron62

    Baron62 Pre-takeoff checklist

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    It appears to be calibratred correctly. G5 HSI mag heading agrees with the wet compass.
     
  7. WannFly

    WannFly Pattern Altitude PoA Supporter

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    did you figure out what was wrong?
     
  8. Baron62

    Baron62 Pre-takeoff checklist

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    I have not returned to the Avionics shop yet because I am waiting on the Garmin 796s to be in stock at the end of the month and do both at one visit. I believe the problem is due to the Century 21 AP "DG Select" ground not being removed. The shop followed the Garmin install instructions, but I think they are incorrect for an airplane going from a DG to an HSI. Hopefully in 2 weeks I will get back to the shop. The GPSS steering has been working great. Very nice feature. I will update the findings after we remove the DG Select ground.
     
    Last edited: Feb 19, 2018 at 8:32 PM
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  9. Baron62

    Baron62 Pre-takeoff checklist

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    My G5 HSI just died completely. The display will not come on at all. Not with Battery bus power or with the unit power button. For some reason the shop connected the G5 HSI to the Battery bus instead of the Avionics bus. I will be calling them tomorrow to schedule an appointment.