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AndyRV7
05-16-2017, 08:29 AM
I am planning a long flight tomorrow and hope to be able to use the newly installed A/P. Last time at the hangar, I had worked out the last of the gremlins and the A/P seemed to be behaving in a logical fashion, with one exception. I could not get it to fly a direct-to, or a flight plan, entered into my GRT Sport EFIS. The A/P seems to be following some green course line instead, and I cannot identify the source of this line.

I do recall reading a reference to a green course line of sorts in one of the owner's manuals for the A/P or the EFIS, but I haven't been able to find it since. When I have tried to follow a direct-to or flight plan, I have been in ENAV in the EFIS. So I would think that even if the green line is a selected heading line of some sort, it would be missing from the map display while I was in ENAV instead HDG mode in the EFIS.

Does anyone have any ideas for what might be happening? I presumed I could try to figure it out next time in the plane but I'd rather have some knowledge of the situation before I get to the hangar tomorrow morning.

Thanks!!

lr172
05-16-2017, 11:53 AM
On my HXr, the flight plan course line is white and the green line originating in the center of the rose/plane icon is slaved to the heading bug. Sounds like your TT is following the heading and not the course. You can confirm this by resetting the heading bug and see if the TT follows it. I use the GRT AP, so don't know much about the config for external AP's. I would speculate that your config is wrong and when in enav mode, the course data is going somewhere other than the TT or not going at all. I would bet that the GRT provides heading and track data at all times on the interface ports and the TT is using that heading as a default when activated, as it is not getting any other course data to follow. I would call GRT and go through your configuration settings.

Larry

AndyRV7
05-16-2017, 12:50 PM
That sounds just about exactly correct Larry. Thanks.

AndyRV7
05-16-2017, 02:03 PM
GRT says the A/P control unit has to be in NAV mode for the EFIS to tell it what course to fly. Otherwise it ignores the course and will fly heading instead.

BobTurner
05-16-2017, 02:31 PM
GRT says the A/P control unit has to be in NAV mode for the EFIS to tell it what course to fly. Otherwise it ignores the course and will fly heading instead.

Just to be clear for those who don't read thread titles, this is true for TT autopilots, but is not true for Trio Pro autopilots...

jeffkersey
05-16-2017, 02:42 PM
I have a TT Gemini AP. I do not have an efis that is will communicate with. I do know that the auto-pilot must be in GPSS mode (toggle left to enter GPSS mode) to fly a flight plan.

AndyRV7
05-16-2017, 02:52 PM
I have a TT Gemini AP. I do not have an efis that is will communicate with. I do know that the auto-pilot must be in GPSS mode (toggle left to enter GPSS mode) to fly a flight plan.

I felt like I came so far but I still feel like a noob. Yes, apparently, you have to use the GPSS mode to allow the EFIS to control the A/P. Such a simple fix.:o

jeffkersey
05-16-2017, 05:12 PM
I felt like I came so far but I still feel like a noob. Yes, apparently, you have to use the GPSS mode to allow the EFIS to control the A/P. Such a simple fix.:o

Glad that it was an easy fix. I have been happy with the way the autopilot flys but the negative about this unit is the interface. In turbulence, it is easy to make unwanted input changes. You will probably not have those issues as you have dedicated knobs and buttons on the efis.

Tailwinds and Blue Skys...
Jeff

AndyRV7
05-16-2017, 05:40 PM
Glad that it was an easy fix. I have been happy with the way the autopilot flys but the negative about this unit is the interface. In turbulence, it is easy to make unwanted input changes. You will probably not have those issues as you have dedicated knobs and buttons on the efis.

Tailwinds and Blue Skys...
Jeff

Someone suggested to me to kind of pinch the toggle between two fingers and use my thumb to push it. I've gotten better at that. Pushing the toggle in was really the only input that was difficult. Give it a try. It helps a lot to stabilize the toggle with your fingers. But I know what you mean. Tomorrow will be my 1st successful flight using the EFIS as a control (should be anyway...). I am excited to see how that goes. I never minded just using the A/P unit itself.

jeffkersey
05-16-2017, 08:01 PM
I have been using that method already. Sometimes in turbulence I accidentally toggle while I am rotating the knob. Also, it is sometimes hard to do fine tune heading adjustment (1 degree at a time). You have to push in and rotate at the same time.... It fly's fairly smooth when it is engaged and it has made single pilot IFR much easier...

AndyRV7
05-17-2017, 04:55 PM
I hear ya. I flew to NC and back to NJ today for a Pilots-n-Paws rescue. The A/P worked flawlessly but I still used the control head for control wheel steering around a couple restricted air spaces, and I did have to use the 1 degree increments a few times. But it was still great. I'll have to play around with the EFIS control for a while before I decide, but I think it might be simpler to control the A/P with the A/P itself. For example, to switch between GPSS and HDG, all I have to do is move the toggle once to the left. I presume I can accomplish the same using the EFIS but I have to push a few buttons or worse to make the same change. Same for vertical steering. I can do it in the EFIS but I have to toggle back to the PFD from the map (my preferred enroute screen) to input the altitude and VS choices. Maybe I am just not an expert yet.

Either way, having the A./P is wonderful!!!