GTN-650 as Primary Nav Source

[Mark_Dickens]

My SkyView system will have a GTN-650 connected through the ARINC box. I want to set up the SV system such that when the GTN-650 GPS signal is available, it is the primary GPS nav source, and when the GTN-650 is not available, it falls back to the SV GPS antenna. Can the SkyView system be setup for this?

 

[60av8tor]

You have to manually select the nav source, but, yes, several may be used by the SV.  I've never thought about it before, but I'm not sure if you can select a default nav source, or if the unit just stays on the last source selected (I believe the later).  Not sure when your 650 wouldn't be available, but SV would be..?

 

[paul330]

Installation Guide p4-20.

This may soon be out of date as Dynon are promising an update soon which will allow GNS430-type data and flight plans to be displayed on the map. My advice would be to wait a little while and watch this space.........

 

[dynonsupport]

If all you mean is position, you can do this easily. Just change your Dynon SV-GPS-250 from POS1 to POS2.

The system uses POS1, then GPS1, GPS2, GPS3, GPS4, then POS2, POS3, POS4.

HOWEVER- The GTN is not as good as our GPS. The GTN only updates position once a second, while our GPS is 5 times a second. Our GPS also has higher positional accuracy.

We very much recommend that you use our GPS as the primary and the GTN only when a failure occurs, which is the configuration SkyView ships with.

If you mean sharing the flight plan from the GTN, that is something that will be supported in a future update.

If you mean the HSI NAV source, you always need to swap those manually.

 

[Mark_Dickens]

If all you mean is position, you can do this easily. Just change your Dynon SV-GPS-250 from POS1 to POS2.

The system uses POS1, then GPS1, GPS2, GPS3, GPS4, then POS2, POS3, POS4.

HOWEVER- The GTN is not as good as our GPS. The GTN only updates position once a second, while our GPS is 5 times a second. Our GPS also has higher positional accuracy.

We very much recommend that you use our GPS as the primary and the GTN only when a failure occurs, which is the configuration SkyView ships with.

If you mean sharing the flight plan from the GTN, that is something that will be supported in a future update.

If you mean the HSI NAV source, you always need to swap those manually.

Two problems with the assertion that the Dynon receiver is superior: 1-it's not certified for /G or IFR approach operation, and 2-you're not right about the update freq...the GNS was once per second, but the GTN is 5 per second. See https://buy.garmin.com/en-GB/GB/aviation/avionics/gps-nav-comm/gtn-650/prod67884.html for more info.

 

[dynonsupport]

Mark,
The issue is that while internally it is a 5Hz GPS, it doesn't send GPS out at 5Hz, only at 1Hz. So all SkyView sees is an update at 1Hz, even though the GTN is faster inside. It was never designed to be a "GPS position source" for other equipment in the plane. The 430W was a 5Hz GPS as well and had the same output rate issues.

Just because SkyView is using the position from the GTN doesn't make SkyView certified. A certified GPS means the position sensor, all the software, and the databases are all certified. The GTN is your primary navigator, and you must be looking at that when in IFR. You can use the CDI on SkyView because that is displaying a direct command from the GTN, but not the map portion of SkyView, since all the databases and such come from our own certified equipment. Thus, it really doesn't matter which GPS position sensor SkyView is using in IFR. You are legal by having the GTN, as long as you use the GTN itself as your primary navigation.

In the end, if you feel more comfortable with the GTN as your primary position source, that is supported as I mentioned. We just very much believe that your experience will be better with the SV-GPS-250 as your primary. Either way, one of the awesome and unique things about SkyView vs. other experimental GPS units is that we do support multiple GPS inputs and can fail over automatically. We even give you a warning if a position source fails.

We've had a lot of experience with all of this integration and the ins and outs of IFR requirements in an experimental (I have a GTN in my personal plane), so let us know if there is anything else we can do. There's a lot going on here!

 

[Mark_Dickens]

Mark,
The issue is that while internally it is a 5Hz GPS, it doesn't send GPS out at 5Hz, only at 1Hz. So all SkyView sees is an update at 1Hz, even though the GTN is faster inside. It was never designed to be a "GPS position source" for other equipment in the plane. The 430W was a 5Hz GPS as well and had the same output rate issues.

Just because SkyView is using the position from the GTN doesn't make SkyView certified. A certified GPS means the position sensor, all the software, and the databases are all certified. The GTN is your primary navigator, and you must be looking at that when in IFR. You can use the CDI on SkyView because that is displaying a direct command from the GTN, but not the map portion of SkyView, since all the databases and such come from our own certified equipment. Thus, it really doesn't matter which GPS position sensor SkyView is using in IFR. You are legal by having the GTN, as long as you use the GTN itself as your primary navigation.

In the end, if you feel more comfortable with the GTN as your primary position source, that is supported as I mentioned. We just very much believe that your experience will be better with the SV-GPS-250 as your primary. Either way, one of the awesome and unique things about SkyView vs. other experimental GPS units is that we do support multiple GPS inputs and can fail over automatically. We even give you a warning if a position source fails.

We've had a lot of experience with all of this integration and the ins and outs of IFR requirements in an experimental (I have a GTN in my personal plane), so let us know if there is anything else we can do. There's a lot going on here!

Thanks for the explanation...it's amazing the little details that are totally left out of all the documentation. Disappointing that the GTN only updates 1/sec as I was advised otherwise by one of your dealers, but I believe you nevertheless. Now I need to think about this some more...

 

[dynonsupport]

Well, the nice thing is that it is just a software selection in SkyView. You can always try it both ways and check and see what works best for you.

I know there is a ton of data so it's hard to remember or even read it all, but page 2-19 of the install guide does cover the 5Hz/1Hz issue.

 

[Carl_Froehlich]

I have 160 hours on the GTN-650 and dual SkyView install in an RV-10. I just finished (finally) my Instrument ticket as well so I have a lot of recent time on the GTN-650.
First - the GTN-650 has been back to Garmin twice already - and on my dime as the guarantee ran out just before the first problem.
Second - the SkyView has never failed and doing a GPS approach with the installed approach chart data base is great. The GTN-650 has on multiple occasions decided to drop track on a GPS approach. At one local airport it has dropped track on every approach at each runway. Garmin tells me to turn off my cell phone and try again - I have not yet had a chance to see if this makes a difference.
Bottom line - the GTN-650 is an overpriced, problematic but certified GPS nav. If I knew the GTN-650 was such a poor value I would have gone with another option. The SkyView GPS and map software are must have backups.

 

[Mark_Dickens]

I have 160 hours on the GTN-650 and dual SkyView install in an RV-10.  I just finished (finally) my Instrument ticket as well so I have a lot of recent time on the GTN-650.
First - the GTN-650 has been back to Garmin twice already - and on my dime as the guarantee ran out just before the first problem.
Second - the SkyView has never failed and doing a GPS approach with the installed approach chart data base is great.  The GTN-650 has on multiple occasions decided to drop track on a GPS approach.  At one local airport it has dropped track on every approach at each runway.  Garmin tells me to turn off my cell phone and try again - I have not yet had a chance to see if this makes a difference.
Bottom line - the GTN-650 is an overpriced, problematic but certified GPS nav.  If I knew the GTN-650 was such a poor value I would have gone with another option.  The SkyView GPS and map software are must have backups.

That's not good to hear. I wonder if the antenna placement had anything to do with it dropping track.  Where is your antenna mounted?

 

[Mark_Dickens]

Well, the nice thing is that it is just a software selection in SkyView. You can always try it both ways and check and see what works best for you.

I know there is a ton of data so it's hard to remember or even read it all, but page 2-19 of the install guide does cover the 5Hz/1Hz issue.

Ah yes, there it is...as many times as I've read through that guide, this totally escaped me. I guess I had it in my mind that if the GTN updated 5/sec, the SV would get that data 5/sec....but you know what happens when you assume, right?

 

[fby757]

I am just getting the first few hours in my RV7 with the GTN 650 install. I bought it because of the approach database. Love the Skyview and looking forward to figuring out the interface between the two and the autopilot and can't wait for a flight plan crossfill update. I would much rather give Dynon my money than Garmin and would have liked to have gotten by on the Skyview alone. However; in the real IFR world (certified or not) a database is the only way to get the approach loaded "fast" enough to keep up with the environment.