Garmin 175 as a position source.

[ZTatZAU]

Thanks for posting jrcox19!

Technically you can do any approved GPS+transponder, but if somebody hasn't already done the analysis/testing, you're on the hook to qualify it yourself. And there's no guarantees it'll pass

Well I do know the GTX335 is listed as compatible in the GNC355 STC install manual. The GNC355 did not exist when I installed the GTX335 so it isn't listed as approved equipment under the 335's STC. I'm thinking though, that a current revision of the GTX 335 install manual or approved equipment list would probably show the GNC355 as approved and compatible.

Can anyone point me to a more current revision of the GTX335 manual(s).

ZT

 

[ZTatZAU]

Like previous poster(s), I'm considering installing a Garmin gps175. Would I be able to/need to use my existing CDI with it? Can that CDI be switched between the existing 12D+ and the prospective 175 if so? Can the existing GPS antenna be shared between the Stratus ESG and the 175? I contacted Appereo months ago inquiring about the possibility of using a 175 as the gps source for the ESG and was told that although that was possible on the ES, there was no field-updateable way to "roll back" an ESG to an ES via firmware or repinning to allow the ESG to accept external gps data. Too bad.. I'd like to avoid installing a second redundant gps antenna.

Thoughts?

I'm not sure about the specifics but the GNC175 install manual (available online) would answer most of your questions.
Good luck with your project MuseChaser! ZT

 

[ZTatZAU]

Thanks for your reply and clarification Dave!

I wasn't responding to you, but also did not see this thread was a reactivated zombie.

In your case, I'd pull the GTX-335 and sell it as they fetch a premium. Once you fly with ADS-B In from a panel mounted source you'll never go back. Personal preference, I like seeing traffic & weather on ForeFlight and the panel in case something happens to the iPad.

I appreciate your suggestions, which all make perfect sense but unfortunately are beyond my financial reach. Due to installation costs, I can only consider installing what Garmin has released to the certified market for installation outside of their dealer network.

I would of course much prefer the 345 to the 335 for all the reasons you mentioned but sadly, for me, it is not likely to be!
ZT

 

[NordicDave]

Thanks for your reply and clarification Dave!

I appreciate your suggestions, which all make perfect sense but unfortunately are beyond my financial reach. Due to installation costs, I can only consider installing what Garmin has released to the certified market for installation outside of their dealer network.

I would of course much prefer the 345 to the 335 for all the reasons you mentioned but sadly, for me, it is not likely to be!
ZT

Yeah, I feel your pain on that front. I've known a few people who have order the experimental versions of radios, transponders, and GPS's and installed it. It the same unit. I think you need to give Spruce an experimental tail number from a buddies plane. the data is not cross-referenced.

 

[bnt83]

Thanks for your reply bnt83!

Yeah! I can see why a SEL flashing could be disturbing! Do you expect this issue to be resolved?

My question here is the same one I asked Jesse above... What altitude will the GNC355 for IFR approaches if there is no pressure altitude available to the GNC355?

ZT

Altitude is all GPS solution, adding uncorrected pressure altitude isn't gonna change that. You won't get VNAV or auto leg sequencing without corrected altitude IIRC, so there is no point to worrying about pressure alt to the GPS.

 

[ZTatZAU]

Yeah, I feel your pain on that front. I've known a few people who have order the experimental versions of radios, transponders, and GPS's and installed it. It the same unit. I think you need to give Spruce an experimental tail number from a buddies plane. the data is not cross-referenced.

I'm not at all comfortable with going that route preferring instead to keep everything legit. With that said, I've heard good arguments for proceeding in this fashion for the second unit of a pair of G5's based on specific language in the STC installation docs that specifically calls out the experimental G5's part number as approved for a second G5.

In the long run, I suppose, it's all up to what your IA thinks and will approve.
ZT

 

[ZTatZAU]

Altitude is all GPS solution, adding uncorrected pressure altitude isn't gonna change that. You won't get VNAV or auto leg sequencing without corrected altitude IIRC, so there is no point to worrying about pressure alt to the GPS.

Thanks bnt! I'm rather an old time VOR/LOC/ILS kind of guy and just now entering the world of IFR approved GPS. I know what you mean by "auto leg sequencing", and my old Piper A/P won't fly them anyway, but can you explain exactly what you mean by VNAV and what that entails?

Are you saying I won't be able to shoot IFR GPS approaches on the GNC355 with vertical guidance (like an ILS) LPV, LP+V, etc... , without somehow providing baro corrected altitude?

 

[bnt83]

Thanks bnt! I'm rather an old time VOR/LOC/ILS kind of guy and just now entering the world of IFR approved GPS. I know what you mean by "auto leg sequencing", and my old Piper A/P won't fly them anyway, but can you explain exactly what you mean by VNAV and what that entails?

Are you saying I won't be able to shoot IFR GPS approaches on the GNC355 with vertical guidance (like an ILS) LPV, LP+V, etc... , without somehow providing baro corrected altitude?

LPV doesn't need pressure altitude or baro corrected altitude.


VNAV and auto flight plan sequencing with altitude legs does.

 

[ZTatZAU]

LPV doesn't need pressure altitude or baro corrected altitude.
VNAV and auto flight plan sequencing with altitude legs does.

Thank you!
I appreciate your reply! ZT