View Full Version : Coupled Approach Woes
09-14-2018, 06:15 PM
I am trying to learn how to use the A/P to fly an approach.
Equip: GTN 650, EFIS HXr, Auto Pilot is Trutrak Vision 385, and
I have the selector switch so GTN can be switched to either EFIS or
straight to the Trutrak.
I have watched Jerry Morris videos but he is using the GRT A/P.
I was told that the 650 will not supply vertical guidance through
the HXr. That to fly the GS after the FAF I have to have the 650
talking directly to the Trutrak.
If anyone is using a setup like mine would appreciate some pointers.
09-14-2018, 06:56 PM
Well, my set up is different: GRT HX (shares nearly all the same software as HXr); Garmin 420W gps and SL-30 for ILS; and Trio Pro autopilot. I also have a 3 pole switch to shuttle the ARINC429 lines, plus the RS232 line, between a direct gps to autopilot connection, or a gps to HX to autopilot connection. But I would be surprised if the GTN output was very different than the 420W, or that the TruTrk can?t read what the Trio does. My set up flies the plane like its on rails, ILS or GPS. It almost sounds to me as if the RS232 line is hooked up but the ARINC lines are not.
09-14-2018, 10:58 PM
My Skyview and SL30 does the coupled ILS quite well. It is dialed in pretty well. I have found I don't want to turn in too early. Needs time to get it all in line.
Not sure what would happen below 200', though.
I also did a VOR approach a while back, IMC. Flawless.
09-14-2018, 11:53 PM
It is very easy, of course if all the wiring is correct
I had a 430W and HX with Trutrak and this was the steps, I would think it would be the same as 650
On your Trutrak, select GPSS, that is all needed, you will not need to touch it again. On your 650, select the approach load and activate it. Lets say it is a GPS approach.
On your HXr, arm the approach (I believe the options are GPS, ILS, LOC and VOR )… you will get a yellow key “Execute” at the bottom of the page. At this point, you are ready and the plane is following the flight plan. Once close to the FF, just push the “execute” and it will capture both the vertical and lateral to the Runway. The Miss button will appear in place of the “Execute”
For the ILS, select your LOC on 650 and load and activate the approach. Set the A/P to heading mode as typically you will be vectored by the ATC but arm the ILS which also the “execute” key will appear on the screen. Each time they give you a heading and altitude, just set those with your heading bug and altitude bug and the A/P will follow those. As you are approaching the FF and they clear you for the approach, push the “execute” and the A/P will automatically switch from Heading to VNAM and once you have an active needle, it will capture it and will follow the lateral and vertical.
As you get more comfortable with this, there are other settings that you can select. You can set your minimum (DA and Miss ) If you push the miss button at any point, the A/P will change to heading and will climb the heading to your selected miss target. If it is a GPS approach, you can have it to fly the publish miss.
It is super easy, very few buttons to select and works like magic.
I miss my GRT setup.
I was told that the 650 will not supply vertical guidance through the HXr. That to fly the GS after the FAF I have to have the 650 talking directly to the Trutrak.If anyone is using a setup like mine would appreciate some pointers.
I am fairly certain that this is not correct. I had a selector toggle switch that I could send vertical guidance directly to GRT or TT. I had set that switch just in case my GRT was not working/dead. Of course never had that issue and always sent the guidance to the GRT which controlled the TT A/P.
09-15-2018, 04:43 AM
If your Vizion isn?t going into gpss mode automatically, then it appears that you may have an Arinc issue. It could be a wiring issue or a software configuration issue on the 650.
On the 650, there is an Arinc diagnostic in the configuration mode. This will show you the data being sent on the Arinc lines. I don?t recall the label name for the vertical guidance, but you should see data from most of the labels. Some labels, like for heading mode will only appear if your EFIS or AP are in that mode. The same with ils and glideslope. You won?t be able to pick this up in your hangar. If you program the gps to go to a nearby airport, most of the labels should have data.
If you want a full feature autopilot with the hxr, I would switch to grt servos. Now that every EFIS vendor is selling their own servos, most can provide more functionality than they can with an external trio or Trutrak AP. For example, I have AFS EFIS and a Trutrak Vizion. I can?t set IAS, but if I had Dynon servos I could.
09-15-2018, 09:44 AM
For example, I have AFS EFIS and a Trutrak Vizion. I can?t set IAS, but if I had Dynon servos I could.
I am not sure if this is for climbing/descending speed if so, GRT is able to do that with TT. In fact I can't think of anything that it can not do with TT Vision that it can with its own Autopilot/servo.
09-15-2018, 08:36 PM
I would suggest getting the GTN 650 connected directly to the autopilot working first so you know those 2 are working together nicely and then move back to putting the EFIS in the loop.