Garmin GNC300XL to GNC355 Transition

Hello all,

I recently bought an RV7A (woohoo!), and would like to start my updates by replacing the existing gnc300xl to a gnc355. Has anybody done this, and if so, how difficult was the replacement?

I am good with my hands but this would be my first RV project.

Amir

First off, congrats on the purchase! Is this a tip-up or slider? Tip-ups make access to the back of the panel relatively easy. Either way, you'll come to appreciate the joy of laying on your back underneath the panel to work on it.

The other installed avionics will also make a difference on how difficult this is. Is the 300XL coupled to an autopilot or CDI? If so, the 355 may not be compatible with either of them, so be sure to check that. Otherwise, you'd potentially need to add an attitude indicator (G5) and autopilot upgrade to the list.

If the GPS isn't coupled to anything, then this could be a very simple swap, especially if you have someone, such as SteinAir, build a new harness for you. My impression is the 355 would fit in the same size hole as the 300Xl, but have never verified.

I had no previous experience before upgrading the transponder and adding an autopilot to my 6A and found it to be a good experience. There were challenges and many things to learn, but I thoroughly enjoyed learning more about my airplane. Hopefully some of the current Bay area RV owners and builders will chime in and offer some assistance. IMO, having the necessary tools and someone knowledgeable to lend a hand or simply bounce ideas off of makes all the difference.

Hey Cole!


Thanks for your response. It is a tip up. The 300 is connected to a trutrak Gemini AP that’s displayed on the Gemini PFD. From my research, it seems the Gemini should still be compatible w the 355 via ARINC. The 355 is also paired with a JPI EDM700. I do plan to add two G5s at some point, just trying to do this one thing at a time to not overwhelm myself, and it “seems” the 355 should be a fairly simple upgrade. That being said, I have no idea what I’m doing lol.

There’s no way to answer your question (‘How hard?’) without looking at the panel, what’s behind the panel, ease of access, etc. Remember the gps antenna will need replacement, too.
If you’d like to fly to LVK, I can offer my unprofessional opinion.

Bob

Upgrade

SwimmingDragonfly96 said:

Hello all,

I recently bought an RV7A (woohoo!), and would like to start my updates by replacing the existing gnc300xl to a gnc355. Has anybody done this, and if so, how difficult was the replacement?

I am good with my hands but this would be my first RV project.

Amir

Click to expand...

Amir,

I did the swap in a RV9A, so if you want to go a a few extra miles and come over the hill to Reno, I can help you make the transition.

Email me at [email protected] and we can discuss if interested.

Brian

Hey Brian,

Thanks for that offer! Even though I purchased the plane a couple weeks ago, it had a couple squawks show up on the pre buy that were just fixed, but now it has gone in for paint. I should have it late December, early January, and would love to hit you up on that offer!

BobTurner said:

There’s no way to answer your question (‘How hard?’) without looking at the panel, what’s behind the panel, ease of access, etc. Remember the gps antenna will need replacement, too.
If you’d like to fly to LVK, I can offer my unprofessional opinion.

Bob

Click to expand...

Hi Bob! I’d be happy to fly over to KLVK once I get my RV. It’s in paint until late December but hopefully we can meet up in January sometime.

Thanks!