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Garmin Take off / go around switch

backcountry

Well Known Member
I have a Garmin G3X with the autopilot.
Two switches can be added.
Takeoff and go around
Control Steering
The wiring from Van’s didn’t include these functions. These switches trigger the flight director and autopilot to these functions.
Question: has anyone added these functions? If so do you where to find the wiring diagram.
 
I have a G3X touch, AP, and GPS175. I installed the GPS175 and TO/GA switch. The TO/GA button has to be a 2NO (a 2 pole) momentary switch.

My engine monitor is a GEA24 which the TO/GA switch connects to one of the discrete input switches on the J244 connector. Pins 40-43 (discrete 1-4). All four of my discrete ins where being used so I had to use one of the general purpose inputs (G5) pin31. I had to use a 5K ohm between p31 and p50 of the same J244 connector to make it an active low. The NO pin on the TO/GA switch get connected to p31 and the common/gnd pin on the TO/GA switch goes to gnd.

The other NO pin on the TO/GA goes to the pin to your gps. In my case J1751 connector p36 on the GPS175.

You then have to go into the config page on the G3X and setup the switch function as well as the TO/GA pitch for both takeoff and TO/GA. For the GPS175 you have to go into the config page and setup or enable the TO/GA function.

While on the ground you can test if the button is working on the both the G3X by seeing the Flight Director bars move and the GPS175 config page

I have control steering on my stick but it has nothing to do with the TO/GA button. Put the TO/GA button on the panel near your throttle

Look on ebay for 16 or 19 mm 2NO 2NC momentary push button. The metal switches are nice for about $10 and are lit.
 
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Thanks for your input. Putting the go around switch next to the throttle is an excellent idea.
Some differences I need to check on.
I have a GTN 625 GPS.
Also I have the GMC 307 autopilot control panel.
 
The point of a TO/GA switch is primarily for IFR. Your profile says RV-12....

TO/GA puts the G3X autopilot into TO (takeoff mode). wings level and pitch up. The other side of the double pole switch tells the GPS to provide guidance for the missed approach procedure. However, the pilot must push the NAV button for the autopilot to fly the missed approach procedure.

It's not clear to me that you'd want either for VFR flight. When I practice takeoffs with an immediate transition to autopilot, which I sometimes do, I do use the TO/GA button, but I could do much the same with setting desired heading, heading mode and vertical speed to a pre-set altitude in Flight Director mode before takeoff, and then push the Autopilot button after takeoff.
 
I use TOGA during my after engine start check list

I use the TOGA to bring up the “scoreboard” on the G3X touch. If you use the autopilot, monitoring the scoreboard is a must. It provides critical information about what the AP is doing. It is the only to verify that the AP is doing what you think you told it to do.
 
Every time I use it I think of...
 

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However, the pilot must push the NAV button for the autopilot to fly the missed approach procedure.

I got a personal email from Garmin on this, so let's give them an A++ for customer support. If the G3X is configured for experimental, my statement is true, but if configured for certified, this is not true. When I installed my system, there was no certified version, so my statement is now out of date. You can have it either way. (I think).
 
Hey Ed

Weird coincidence ! I was just trying to figure this out yesterday for my G3X Touch/GMC307/GEA24/GTN625 system going into my scratch build 4pl Bearhawk :)

Rev AP the G3X Install manual has the first attached image below on page 27-9.

The second attached image below is a clip from my electrical drawings. I chose pin 11 on the GTN (and I will configure it in the GTN when the time comes) and I chose pin 40 on the GEA 24.

Note that there is no connection to the GMC307 directly. That is handled by the G3X.

Cheers
 

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Thanks for the info.

For control steering the installation manual says to use that switch to ground both autopilot servos. However, I don’t see what on the servos what the switch needs to ground.
 
CWS Input

Thanks for the info.

For control steering the installation manual says to use that switch to ground both autopilot servos. However, I don’t see what on the servos what the switch needs to ground.

To activate Control Wheel Steering, you press and hold the AP Disconnect/CWS button. A momentary press of the AP Disconnect/CWS button disengages the autopilot.

Pin 15 on the J281 connector of the autopilot servo is where the AP Disconnect/CWS button is terminated on the servo side.

CWS-M.jpg


Thanks,

Justin
 
Can you Daisy chain the role servo to the pitch serval then to the Control steering switch for a single point ground?
That’s what it looks like to me.
 
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