VOR approach with a GTN650

jwilbur · #1 10-20-2018, 06:16 PM

I have a GTN650 that feeds my Dynon screens. I'm wondering what the proper procedure is to set up for a VOR approach. Let's say I activate a VOR approach. Assume I am not being vectored. Also assume there is no GPS overlay for the approach. Also assume my GTN is properly configured to switch from GPS source to NAV source automatically.

My understanding is that to fly a VOR approach I need to use the actual VOR receiver of the GTN to legally fly the approach. When I activate the approach the GTN is feeding the HSI on the Dynon with the GPS (HSI is magenta). It doesn't switch to green (VOR receiver) when I cross the VOR as I expected it would. It does automatically change all the course settings, etc, so that if I were a skilled monkey I would be able to follow the flight director to fly the approach. But it's not feeding me info from the VOR receiver so I don't think this is a legal way to fly the approach.

I once manually hit the CDI key to switch to the VOR receiver and then activated the approach and the GTN does correctly give me the green HSI but it doesn't then set the course automatically as I cross the VOR and sequence through the procedure turn, etc. I have to do all that manually.

I believe it would be legal for me to fly from the GPS source if I could also get a bearing to the VOR at the same time. Am I right about this? If so does anyone know how to do it with the GTN/Dynon combo? Or is there maybe a better way altogether?

BobTurner · #2 10-20-2018, 06:50 PM

OH my. There was a time when all you had was a VOR receiver and an OBS, which you had to set by hand.....
Okay, back to the 21st century.
Since you said you did NOT put in vectors to final, can I assume that the procedure called for an outbound leg with no nav guidance, followed by a PT and then inbound to the VOR? IF so, the box was working correctly, giving you GPS advisory guidance as you crossed the VOR and turned outbound. Once inbound and intercepting the published leg to the fix, it should have auto-switched to the VOR source and the efis color should have turned to green - but not before that.

IF the procedure title is "VOR" and not "VOR or GPS" then you are supposed to use the VOR, not the GPS, for primary navigation from the IAF inbound.

jwilbur · #3 10-20-2018, 07:01 PM

Quote:

Originally Posted by BobTurner

.... Once inbound and intercepting the published leg to the fix, it should have auto-switched to the VOR source and the efis color should have turned to green - but not before that.

IF the procedure title is "VOR" and not "VOR or GPS" then you are supposed to use the VOR, not the GPS, for primary navigation from the IAF inbound.

This is what I was expecting, but it did not switch when I intercepted the inbound course. It's the VOR-A approach into Culpeper, VA (CJR) that I was flying. I thought I might be misunderstanding how the GTN is supposed to be working. ... Not sure what to check to see why it didn't switch. Any idea?

BobTurner · #4 10-20-2018, 10:08 PM

Really don?t know about the 650. For the 430W there?s a selection (to auto switch, or not) in the setup menu.

terrykohler · #5 10-21-2018, 04:34 AM

What Bob is saying. Your default selection going in is ?vectors?. If you?ve not selected an IAF and just roll into the inbound course, the 650 assumes you?re not on the approach (still being vectored), and will not make the switch.
Terry, CFI
RV9A N323TP

jwilbur · #6 10-21-2018, 06:03 AM

Quote:

Originally Posted by terrykohler

What Bob is saying. Your default selection going in is ?vectors?. If you?ve not selected an IAF and just roll into the inbound course, the 650 assumes you?re not on the approach (still being vectored), and will not make the switch.
Terry, CFI
RV9A N323TP

I wasn't on vectors. I Chose the IAF to be CSV and the gtn flew me direct to it, guided me through the procedure turn and inbound. But it never made the switch. ... I'll make sure I have autoswitch turned on in setup. Maybe it got messed up during the recent software update.

Bob'sRV6A · #7 10-21-2018, 12:17 PM

My understanding is that the GTN650 acts differently for VOR and ILS/LOC approaches. There is no auto switching of the CDI source from GPS to VOR--only auto switching from GPS to LOC. So on a VOR approach, the CDI must be manually switched. There are other differences on how the frequencies are handled as well.

jwilbur · #8 10-21-2018, 12:44 PM

Quote:

Originally Posted by Bob'sRV6A

My understanding is that the GTN650 acts differently for VOR and ILS/LOC approaches. There is no auto switching of the CDI source from GPS to VOR--only auto switching from GPS to LOC. So on a VOR approach, the CDI must be manually switched. There are other differences on how the frequencies are handled as well.

Just checked the manual. You are correct. on a VOR or back course approach, the GTN650 does not automatically switch. Thank you.

-Joe