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G3X GI-275 not an option?

dquite1

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I was just about to finalize my avionics purchase when I heard a rumor that the GI-275 will not communicate with the G3X system?!?

I really don't like the display or the looks of the G5 compared to the GI-275 so a G5 just wasn't an option for me from the start. But if its true that the GI-275 will not communicate with G3X then it throws a wrench in the whole plan. Is anyone aware of this?

My plan was to have G3X with GFC500, GTN650, GNC255, GTX345, and GI-275. I thought about using the GNC255 with the GI-275 but then I have 2 units that are not communicating with the G3X. Would like to have the ability to put a GPS approach in on the G3X and at the same time an ILS approach on the GI-275.

Any advice would be greatly appreciated!!
 
G3Xt

I have a G3X with GTN650, GNC255 and a G5.
The G3X and G5 does not spek ARINC, only CAN BUS.
The ARINC from GTN650 and GNC255 is connected to the GAD29 that
converts it to CAN BUS. The G5 is connected to CAN BUS.
The GTN650 has one RS232 MAP-MX output that goes to both G3X and the G5. So I have both GPS/NAV1/ NAV2 on my G3X and the G5.
The G5 has a built in AHRS wich functions as a stand by AHRS.
MapMX - The preferred data source when interfacing with an external navigator, and is only available from Garmin units with a WAAS GPS receiver. When MapMX data is received, the G3X display can show more accurate information about the external navigator flight plan.
Looking at the Interface options for the GI-275, it will work with the GTN650
and the GNC255. It does not speak CAN BUS only ARINC and RS232.
However the GNC255 can drive the GI-275 via RS232.

https://www.piperowner.org/talk/uploads/editor/kr/fgkw4la43rtu.pdf
 
Yep. You heard correct. The GI 275 cannot provide backup air and attitude data to the G3X flight deck if the flight deck air data LRU goes down. Bu the G5 can do it. So with a GI 275 as a backup EFIS if you are flying along and the G3X GSU 25 goes off line you loose the flight deck instrumentation and have to fly the bird by the GI 275 stand alone. In the same scenario with the G5 the G3X system will fail over to the G5 as a full ADHARS sensor and the full glass flight deck stays online so you can fly conventionally to your destination or alternate. Basically the G5 can step in and take over the functions of the GSU 25 so the G3X keeps on truckin'. With a GI 275 since it wasn't designed to integrate with G3X it has no idea something has happened and that you are now having to focus all your attention on it alone to get you down. Garmin had no intention of combining G3X with the GI series when they designed them. The GI 275 was designed for IFR certified aircraft with dual EFIS or as a backup to the TXi flight deck, which it can do. It caught Garmin off guard when folks wanted to use Gi 275s in experimental airframes much less with G3X.
 
I wish Garmin would be willing to tell me what new products are going to be announced this year. I'm trying to get this lined up for install this summer but with all the product delays they are telling me it will be May if I order now.

If they are coming out with a G6 it would be awesome news, so would a software update for CANBUS on the GI-275.

I had actually considered the G500txi as well but two big issues came to light with that... It doesn't have the AOA capability that I really want and I heard that it cannot drive the GFC500 like the G3X can. Also I heard a rumor that if you have a single display txi system with a backup GI-275 you had to use a second GI-275 for GFC500.

I talked to Garmin tech but they didn't have any advice. Thankyou for everyone's comments!!
 
I talked to Garmin tech but they didn't have any advice. Thankyou for everyone's comments!!

Yes. As Garmin gets bigger and bigger sometimes you get representatives on the phone or at the Oshkosh tent that don't know as much about their equipment as your average home builder. I find it fairly easy to talk to one of blue shirts in the tent and play "stump the chump". Ask if a GNC 355 is a good way to replace a GNC 300XL and they will respond with "What's a GNC 300XL". As about onboard ICAO code randomization for anonymous mode and they get a deer in the headlights look. That being said there is always one or two real techs somewhere in the tent with blood shot eyes surrounded by a crowd of Gomers.
 
Here is one more option for you if you want flight deck ADHRS backup. Since you are experimental airframe you can install two GUS 25 LRU's and configure one as primary and the other as failover. That's how my RV-8 is equipped. Then the backup feature of the G5 isn't as big a deal. Then you can go GI 275 for the look you want while having the flight deck air data/attitude redundancy.

Dual GSU 25's are not allowed in type certificated aircraft so here is another example the advantages afforded EAB aircraft.
 
Although the ADHRS fallback is a big advantage of the G5/G3X system it's honestly not my greatest concern at this point. If ADHRS fails on the G3X I still have the GI-275 to look at.

The problem is... in order to have my ILS approach dialed in to the GI-275 I apparently have to remove the #2 GTN or GNC nav/com from the CANBUS system and dedicate it to the GI-275. With this separation from the G3X system I then also lose the ability to use my touch screen and all the other bells and whistles to control my #2 nav/com.
 
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