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OK, quick update. I "fixed" the EFIS plug Sunday. Although, I am wondering if I even needed to. The wire in question is the ARINC output going back into the EFIS. Since I am only using the ARINC to feed data to my autopilot, I'm not even sure at this point that the return wire is necessary. It seems like my use of the ARINC would be a 1-way task...EFIS>ARINC>A/P!??
So I spoke with GRT again today to update them and ask the next set of questions. During the conversation, GRT felt like my ARINC was actually now working (to be honest, it was probably working all along). It was the ARINC missing data message that made me think I have a problem. But at the end of the day, warning messages aside, it is my A/P that is actually leading me to believe I have an ARINC issue. The warning message may just be a red herring. When I turn the A/P on it tries to bank the plane (right I believe), and try to dive. At that point, I have to turn it back off. Here is where I am grasping at straws. I cannot figure out what the A/P is responding to. I thought that maybe the EFIS was controlling the A/P, whereas pre-ARINC install, I controlled the A/P through the A/P. I'm just not GRT savvy enough to use the EFIS to intentionally control the A/P. Here is why I agree that the ARINC has probably been working all along. Prior to install, the A/P would turn on in track and altitude hold mode. That is it would maintain current steady-state flight. Then, if I wanted to follow a flight plan, I could toggle to the next level of capability,which was GPS NAV. NOW, the A/P turns on in GPSS mode, which is loosely the same as an "enhanced" GPS NAV mode. So, again, ARINC warning message aside, My true problem seems to be I don't know why the A/P is functioning the way it is. GRT seemed to tell me the A/P control head would not fight with the EFIS for control of the actual A/P. One last thing. GRT feels convinced that I have an old EFIS software version. This is why they thought I should be able to tell the EFIS which port the ARINC was on. I am going to check that tonight and make sure I can remove that from the equation. But it's difficult to believe the software would cause the rest of the issue(s). I apologize if someone has given me the answer already in this thread. I am learning this all as I go, so some suggestions may not be obvious yet. Do this make any sense to anyone? Thanks! Andy |
Well, one data point. I installed a Trio Pro and GRT HX well before (like 10 months prior to) first flight. The Trio worked in'stand-alone' mode, but went into a divergent vertical oscillation when controlled thru the HX. After a lot of back and forth, Trio realized I had older software installed. An autopilot software update fixed all problems.
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If it's the EFIS software it's easy to check. Boot it up, go to the main menu, and write down the software version number. Go to the GRT web site, software, and see what the current version is. If yours is old follow the instructions to download the latest version to a memory stick, and from there to your EFIS. For my Trio autopilot, it was harder - I had to send it back for a firmware update.
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I have a boatload of pics of all the important screen in the efis, including the boot. I'll have to send them to my phone so I have them handy. I'm pretty sure I updated everything when I bought the plane but we'll see tonight.
I'm also going to have to learn how to use the EFIS to control the A/P but that should be pretty easy from the manual. Funny thing, I used to feel around behind the EFIS to locate the USB slot. I've had the EFIS out or been under or behind the panel so much with this issue, I ordered and installed a USB cable. |
I have the current software version, so we can cross that off the list.
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I actually went back and read your posts. I had presumed the gps source was something like a 430 or GTN 650 etc. I see that assumption is wrong.
I am not sure that the internal gps units in either a GRT or Garmin EFIS can issue GPSS commands. These are direct steering commands to an autopilot or FD. Try this: on the autopilot, turn GPSS commands OFF (again, whatever is needed. My Trio does it automatically, but I think the TruTraks need a specific on/off). Center the heading bug on the efis heading tape. On the GRT EFIS autopilot menu, enter the current altitude as the desired one, select "heading" on the GRT autopilot menu; engage the autopilot. How does that work? Use the left EFIS knob to move the heading bug. Does the autopilot follow it (turn)? If okay, try changing heading to ENAV in the autopilot menu (GNAV only works with GPSS commands). See if it intercepts and follows whatever GPS course you have (previously) entered. |
I'll try that this weekend Bob if I get back to the plane. I am virtually certain the internal GPS can send the GPSS data as long as I have the optional ARINC installed. That's why I paid the $500 bucks for it. I am supposed to be able to control the Gemini A/P from the EFIS with the ARINC module. I should also be able to fly a HITS approach to any runway in the EFIS database. I figured it would be a good safety tool if I ever got irresponsible and caught in IMC.
That really is the last thing I can try. I read through the A/P section of the GRT manual. So once I make sure the EFIS isn't confusing the A/P in some way that I may have inadvertently told it to, I am out of options. Thanks for sticking around!! |
One last question: If you totally disconnect the autopilot from the EFIS, will it at least attempt to maintain straight and level when turned on? I think it should.
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It was always the EFIS driving the A/P, now it still is, but through the ARINC module. I would have to pull pins from the A/P plug to test it. If we are trying to see if the A/P works, that IS a question mark. It worked while attached to the EFIS without the ARINC. But the airspeed tape was off. It read 49 knots in the hangar. So I sent it back to Trutrak. I just can't remember if installed the ARINC while I still had the functioning A/P in the plane.
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