GTN-HXr-TT Vision 385 Killing Me

I am working on my instrument ticket. Learning to fly the 9A by hand
has been enjoyable. Then my instructor said it's time to make the plane
fly the approach on auto pilot. Progress came to a halt.
Trying to learn how to couple the 650 to the HXr and to the AP has been
a major hassle. I have found nowhere to go to read up on this combination.
On GRT, I watched Jerry Morris videos but he is using the GRT AP and
servos. Closest I have come and learned a lot.
I have a toggle switch on the panel that directs the 650 output to either
the EFIS or directly to the AP.
My instructor knows Garmin but nothing about GRT, and he says, rightly,
I have to be able to know exactly what the airplane is going to do when in
the electronics are flying mode.
Friday we took off from KREG on 17 and he wanted me to let the plane fly
the RNAV for 35 to save some time. The feed from 650 going to EFIS.
After takeoff, loaded the approach on the 650, going to vectors and then
hitting EDUYA the IAF. I was level at 2K in the Heading/Altitude mode
on AP on the EFIS. I then armed the AP on the EFIS for the approach
and the EXECUTE button was at bottom of screen. I was slightly NNW of
IAF about 2 mile out. I hit the EXECUTE button and the AP, which was
showing GPSS VS (GPS direction mode) then slightly corrected to head
directly for the IAF. The 650 was calling for a tear drop entry into the
holding pattern for the turn back to final. When plane crossed the IAF,
instead of flying the tear drop it turned LEFT to loop back to the final
approach course. So instructior told me to turn it off. I then said let's
try by feeding the AP directly. Cleared EFIS and 650, flipped switch
to feed AP from 650 directly. Plane then flew a perfect approach to DH
like on rails. We then tryed a second time with the switch to EFIS with
same results as first time. I took some pics of screens on second try.

The shot of the EFIS shows the left hand turn and I brought up the
settings at the bottom. I then saw that even though the settings were
for GNAV and GPSV the top left is showing I am in ENAV!!! HOW???
All the setting say other wise!



These two shots of 650 showing flight plan and map showing it wanted
to fly the tear drop. By the time I took shot of Map page, we had almost
completed the turn to Final.





I have been told several times by GRT that when the 650 is feeding the
EFIS, the EFIS is just a pass through to the AP.

At this point don't know where or what to do next.
Any thoughts, suggestions or what ever would be Greatly Appreciated
at this point.

Same thing with ifd 440

Hi. I fly my rv-10 with 3 horizon hx and a avidyne ifd440.
When it?s a rnav approach, i let the autopilot be feed by the grt avionic. You need to set the gpsv ( in the approach key in the same menu as loc, ils, gpsv etc) and it will make a perfect approach. ) same thing if you fly a straight in approach.

But if you want to do an automatic entry, hold or procedure or procedures turn, the grt don?t recognize it from the gps. You need to flip the switch to have hour gps directly talking to the trutrak autopilot. Be aware that during this time that you feed the autopilot directly by the gps, you will have no control on hour altitude with the grt avionic. You need to control it with the autopilot ( either altitude hold or vertical speed). I flip the switch back to normal position ( autopilot feed by grt) when in final.

Be aware too that when the autopilot is control by the gps directly, even if you are on ils or vor setting on your garmin and even if it show you a vor or ils on your grt screen, the autopilot will be following the gps track. Not the ils or vor.

I wish it was easier than that but since i begin to fly ifr, technology nust make the renewal test easier and easier. It feel lime cheating now to have the entry, hold and procedure turn all done by the autopilot. And the navlog done by foreflight!!

In my last plane, I had the HX instead of the HXR and flew all these approaches perfectly and never needed to feed the A/P directly from the GPS.
- On your GRT, make sure the source for navigation is the 650
- Set the A/P on GPSS and drive it from GRT (this includes for heading mode and altitude preselect)
- On GRT, set the A/P mode to ENAV
- Arm the correct approach (GPS, ILS,..)
- If being vectored, stay in the heading mode to follow ATC instructions
- On your final leg as you are getting cleared for approach, press execute
In this even if you are still in the heading mode, the GRT will flip to GNAV automatically as soon as you have an active needle and will follow it perfectly.

MY GRT/TT autopilot operation was much simpler and required fewer button push than my current Garmin. To make things simple for myself, I always put the TT in GPSS mode and drove it via the GRT.

GNAV vs ENAV

On the GRT HXr if the 650 is feeding it while in the enroute phase of flight the NAV indicator on the scoreboard will say GNAV. It will stay in GNAV until you intercept the APPROACH and the annunciation will then say ENAV. You may select ENAV on the menu enroute but I don’t think the Garmin steering commands such as early turning at waypoints works. GNAV will be indicated on the scoreboard when the HXr is utilizing the Garmin steering commands until the approach segment, then ENAV is correct. The autopilot select option will still say GNAV.
I also note the the vertical select option is in VS. Try AUTO there and it should climb, descend or auto capture the glideslope. This works with GRT autopilot. TT may be differen5.

Procedure Turn

Jerry, have watched your videos many times. That?s how I learned
to arm EFIS for approach.
How do I get it to fly the turn (which GTN is directing) when gtn is feeding
the EFIS?

Caveat: I have a Trio Pro autopilot. Among other differences from the TruTrak, it automatically defaults to ARINC commands from the EFIS - no buttons on the autopilot to push, beyond engaging the servos. With a TT, make sure it is in the proper mode to accept EFIS commands.
Inbound to the IAF, you want to be in GNAV mode. In this mode most of the GPS commands are passed thru to the autopilot. In particular, ONLY the GNAV mode will fly a procedure turn, and only if it's supported by the GPS (which it is for any of the Garmin 400, 500, 600, or 700 series). Do not push "Execute" prior to the procedure turn. Push Execute after established inbound, on the proper heading, to the IAF. Once inbound, the GRT will change to ENAV, using its internal software for left-right commands. (Again, only GNAV will do turn anticipation, but presumably that is no longer needed once established inbound). If you miss, the EFIS will automatically return to GNAV. If you want something else, you can select that from the EFIS menu once the autopilot is in approach mode (changing the mode after this time will only become effective on the miss).
I can say that, with my combo of G420W, HX, Trio Pro (with auto trim), I can fly a flight from just after lift off to just before the landing flare, complete with a procedure turn, just pushing buttons (and using the throttle for speed control - the autopilot will keep it in trim). It's actually embarrassing, it flies much better than I can. So if it's set up right, it will work.

Edit: Bert, I think you are hitting EXECUTE too soon. I think if you want to do a course reversal, you need to wait until you're inbound, on course, to the IAF. I'm not positive, but I think the Execute screen button is now optional. You can turn it off, and the software will just figure it out on its own. But I haven't tried this yet. I like to think I have some control!

Thanks Bob

Thanks will give it a try. I have been in HD/Alt mode heading in direction
of IAF. I would then arm the AP as seen in the pic.
You are saying that after loading and activating approach in 650 then go to GNAV under Lat A/P, then in ARM (CAPT) choose GPSV, set DH and missed and
the execute button will be showing, but I will be flying the turn in GNAV.
Then after turning final hit Execute button, right?

That sounds right.

BobTurner said:

Edit: Bert, I think you are hitting EXECUTE too soon. I think if you want to do a course reversal, you need to wait until you're inbound, on course, to the IAF. I'm not positive, but I think the Execute screen button is now optional. You can turn it off, and the software will just figure it out on its own. But I haven't tried this yet. I like to think I have some control!

Click to expand...

A little background on the EXECUTE button.

Prior to having it you could get into real ?legal? trouble because the autopilot would intercept the glideslope and descend. If you had been cleared for the approach this was OK. If not you could have been setting yourself up for an altitude violation. It didn?t matter what altitude was set in the window, the a/p would depart and descend. The EXECUTE button is their for a reason so be sure you really want to do away with it?s protection before you disable it.

Bayou Bert said:

Jerry, have watched your videos many times. That?s how I learned
to arm EFIS for approach.
How do I get it to fly the turn (which GTN is directing) when gtn is feeding
the EFIS?

Click to expand...

Bob is correct. GNAV for everything until you want to intercept the glideslope. Inbound when ready to depart holding or procedure turn, then EXECUTE. GNAV will switch to ENAV on the scoreboard and down you will go. Vertical should already ge set to AUTO.

RV8iator said:

A little background on the EXECUTE button.

Prior to having it you could get into real ?legal? trouble because the autopilot would intercept the glideslope and descend. If you had been cleared for the approach this was OK. If not you could have been setting yourself up for an altitude violation.
it.

Click to expand...

Jerry, I agree the PIC is responsible for everything - but isn?t this also an ATC failure? I didn?t think they were supposed to ever have you intercept glide slopes from above.

Success!!! Super Thank You

After reading the post this morning, couldn't wait to get to airport
and jump in Pearl to go try recommendations. I flew exactly as I did
on Friday, approach IAF from NNW, loaded the approach in 650 and
activated, armed the EFIS as shown in pic above hit exit.
Yellow activate button present but now in GNAV, plane turned toward
IAF, flew the tear drop and when we straightened out on final I hit the
activate button. Flew the approach perfect.
Thanks to everyone for the help with this lack of knowledge.
Just shows the power of the Vans Forum
Jerry and Bob thank you very much for the explanations and help.
Now I can get on with the training.

Below shot of Pearl sitting in front of hanger at Hooks in Houston
on recent trip.
Thanks a Million!!!

BobTurner said:

Jerry, I agree the PIC is responsible for everything - but isn’t this also an ATC failure? I didn’t think they were supposed to ever have you intercept glide slopes from above.

Click to expand...

When we noticed it happening we were below glideslope but well away from airport. Level at 3000 feet with 3000 set in the altitude window. Glideslope came down and a/p captured and started descent without clearance from controller.
Big picture scenario we discovered was the plane would depart a selected altitude even if not directed. In other words it would just descend whether you told it to or not. It did happen on an actual flight so not out of the realm in busy IFR world. It was 100% repeatable.
Many discussions about it, but an autopilot should never do something that would get you violated or worse with no pilot input. Hence, the a/p now will not fly away from a selected without the pilot giving it permission.

The autopilot will not capture from above, nor will a controller direct you to.