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Posted

My Mooney 252/Encore has a G500 and KFC 150 autopilot with altitude preselect. The preselect is now inop and I’m consider installing Garmin’s GAD 43e unit so I can altitude preselect directly on the G500. A GAD 43 is already installed, but doesn’t allow altitude preselect but the GAD 43e does. Has anyone done this upgrade and /or installed a GAD 43e?

Posted
On 1/19/2022 at 10:24 AM, Jungle Pilot said:

My Mooney 252/Encore has a G500 and KFC 150 autopilot with altitude preselect. The preselect is now inop and I’m consider installing Garmin’s GAD 43e unit so I can altitude preselect directly on the G500. A GAD 43 is already installed, but doesn’t allow altitude preselect but the GAD 43e does. Has anyone done this upgrade and /or installed a GAD 43e?

I'm replacing the preselect in KFC150 with aG500 and GAD43e because it seemed too difficult to retain all the parts required to keep the altitude select working with the KAS297B.  Not impossible, but difficult.  So if yours was working, I will have the parts you may need to repair.

The KAS297 needs a grey code input from either the original KEA130 altimeter or a 'new' blind encoder.  It also needs a baro correction from the original KEA130, or from something like a GI-275.

I will be able to give you feedback on my GAD43e install soon.  Biggest issue so far has been the $$$ for the brick.

 

Aerodon

 

 

  • 5 months later...
Posted

Hello Aerodon,

What’s the progress on your GAD43e install?  I have an existing analog encoding altimeter but can my G500 supply the grey code instead? Do you have a copy of the GAD43e installation manual?  
Thanks, Dave

Posted
35 minutes ago, Jungle Pilot said:

Hello Aerodon,

What’s the progress on your GAD43e install?  I have an existing analog encoding altimeter but can my G500 supply the grey code instead? Do you have a copy of the GAD43e installation manual?  
Thanks, Dave

You’ll want to quote him or ping him @Aerodon so he knows you’re looking for an answer

Posted
59 minutes ago, Jungle Pilot said:

Hello Aerodon,

What’s the progress on your GAD43e install?  I have an existing analog encoding altimeter but can my G500 supply the grey code instead? Do you have a copy of the GAD43e installation manual?  
Thanks, Dave

No I haven't finished the install.  Yes I have manuals for you - send me an email supercub180@gmail.com

No the G500 has no grey code output, at best the Garmin equipment has a serial altitude (no use) and a baro correction.  My plan is to keep a blind encoder for the KFC150, and use the GI-275 or GAD43e for the baro correction.

I will have 3 'altitude sources' in the plane - ADC74 airdata (master), GI-275 and the blind encoder.   My KAS297 already does not capture the correct altitude, took me a while to work out that it does work, but captures 300 feet high.  And there is a blind encoder, I suspect that was installed to make the GPS and transponder accurate, and there is an error in the KEA130.  

Aerodon

 

 

 

  • 2 years later...
Posted

@Jetpilot86 I'm slumming it with my G500.   :)

 

How did the process work?  Did you have to actually do any wiring changes or was it basically plug and play?

Posted

@wombat Maxwell did it for me, but I believe a wire for the altitude selector had to be run from the unit, in the avionics bay, to the PFD/Autopilot as part of the process. 
 

They may even still have my old KI275 altitude selector if someone is hunting one. 

  • 7 months later...
Posted (edited)

Finally got my GAD43e upgrade completed.   No additional wires needed in my case.    One hiccup in that on the GAD43e configuration page on the G500, the installer initially selected "King KAS 297" for the type, but it had to be set to the "King KAS297B".   When I flew home I couldn't get it to work, then after about 30 minutes of digging online I figured out the KAS297B seemed to be necessary.  So I flew back over and the installer was able to update that and now it works.

 

I love the level-off at altitude, it's super smooth.  And as I continue to age (for 25 to 35 years hopefully) I expect that will prevent me from overshooting an altitude.

I wasn't sure how it would handle the altitude hold after level-off at a preselected altitude, but it does actually turn on the altitude hold mode on the autopilot.

For operation, when you select an altitude or vertical speed on the G500, it notifies you to hold the ALT button to select altitude capture or V/S set and capture.   When you do press and hold the vertical speed, it will set the vertical speed to your current, and then you twist the knob to adjust it.

Really looking forward to selecting an altitude at a waypoint, looking at the vertical speed required on the GTN750, setting that in the G500 and watching it fly me there.   :D

It's not actually a vertical nav system like if I had the GFC500 autopilot, but it's still pretty great!!

G500 with GAD43e operating in Mooney Rocket.jpeg

Edited by wombat
  • Like 2
  • 1 month later...
Posted
On 10/12/2025 at 7:08 PM, Aerodon said:

I have a spare GAD43e for anyone who wants to do this....

 

Aerodon

The shop didn't have to run any wires for my upgrade.   If you have a G500 series and legacy compatible autopilot (KFC, KAP, etc) this is a great deal.

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