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Replacing GTX327 with GTX330, but which one?

So I just bought an experimental plane in the US, which as ADS-B via an “uavionix Echo UAT” but it sends on UAT and not on 1090 MHz. Apparently it is illegal to use this uavionix Echo UAT in Europe. Also, there is a GTX327 Mode C transponder, but it seems it is illegal to fly without Mode S transponder.

So it seems I need to urgently upgrade to Mode S before flying the plane to Switzerland.

Is it as easy as replacing the GTX327 with a GTX330 (they seem to have the same size, and the GTX330 should play nice with the G600 in the plane?) and turning off the uavionix Echo UAT permanently in Europe (but keep it on while flying in US)?

If yes, which one of the GTX330 would be suitable? it seems there are at least 4 different variants: https://www.seaerospace.com/sales/search/gtx330

My use case is to fly within European airspace, and do a ferry flight from US to Europe.

Is this something that an A&P can do by himself or do I need an avionics shop to do the replacement?

Switzerland

The plain GTX330 should be sufficiënt for Europe (not for the US). Mine is coming out in februari, should you wish to wait that long.

EBST, Belgium

I paid £1700 to upgrade my GTX 330 to a GTX330 ES so that I would be permanently emitting Certified ADSB regardles of what other equipment I use for traffic awareness. So I would suggest considering if that is a requirement for you, now or later.

Last Edited by GA_Pete at 11 Aug 10:00
United Kingdom

February is too late, sorry airways.

Do I understand correctly that GTX330 ES is sufficient and there is no real benefit for me to get the GTX330 DES (w/ diversity). I understand the Diversity aspect is a second antenna “switching capability” that can extend range/direction (especially above). It seems overkill for a non-jet, but maybe I am missing something.

About GTX330 plain vs GTX330 ES: it seems like price difference is ~600 USD, so maybe go for ES directly? ADS-B out increases situational awareness of planes around me, correct (vs just Mode S)? Also, if I ever want to fly it back to USA, ADS-B is mandatory (?), so might be an advantage from that point of view.

Switzerland

HBadger wrote:

About GTX330 plain vs GTX330 ES: it seems like price difference is ~600 USD, so maybe go for ES directly? ADS-B out increases situational awareness of planes around me, correct (vs just Mode S)? Also, if I ever want to fly it back to USA, ADS-B is mandatory (?), so might be an advantage from that point of view.

What about the 335/345? They not much more expensive…

EGTR

Yes, if you want to fly back then ES is a better option. Diversity is important when flying in Canadian airspace (from 2023 on ?). I’d encourage everybody to switch to ads-b out.

EBST, Belgium

You will have a possible issue with installing a GTX330 in place of your GTX327 as long as you have the uavionix installed as they are not compatible.

From the install manual:

A companion Mode A/C (not Mode S) altitude-reporting transponder is
required to be installed for 14 CFR 91.225 and 91.227 compliance, unless
installed on an aircraft excepted from the requirements of 14 CFR 91.215
and 91.225.

You can install a GTX330ES model if you have a valid GPS source (GNS or GTN) in your new aircraft. Then disable or remove the uAvionix device. Installing a GTX330ES will make your aircraft visible to aircraft with ADS-B In, either portable or installed, but the GTX330ES is ADS-B Out only and does not receive ADS-B traffic.

If you decide to install a GTX330 (not ES), you will have to disable the uAvionix system. If you can avoid B/C airspace and stay below 10,000 MSL, you don’t need ADS-B Out in the US. ADS-B Out is an airspace rule and is not required for IFR flight per say. You can even request a one time exemption to fly in ADS-B rule airspace if you need it by using an online system setup for that purpose, see https://sapt.faa.gov/adapt-start.php

It may be legal to have an A&P replace the GTX327 with a GTX330, but I would not recommend it. Definitely I would not recommend it if you install a GTX330ES and have it setup for ADS-B Out.

The GTX330ES-D is probably over kill, but with a top antenna, you can be tracked by the Aireon satellite system which may end up being used over the ocean and over Canada. Since your airplane is experimental, if it is not a metal fuselage, a bottom mounted antenna may suffice.

If it were my decision, I would install a GTX345.

KUZA, United States

Transponder diversity requirement depends on aircraft type. According to CS ACNS.D.ELS.065, you only need diversity for MTOW > 5700 kg or maximum cruising TAS > 250 kts.

LKBU (near Prague), Czech Republic

NCYankee wrote:

If it were my decision, I would install a GTX345.
My position as well. Next best is a 335, and only then a 330ES.
ESMK, Sweden

Yes I’m coming around to the gtx345. And disable/remove the uavionix. That way I have mode s, adsb in and adsb out.
Can also show traffic on the existing G600. (There is also a gns 530 w in the panel).

I’m potentially going to upgrade to G3X later, so the gtx345 is hopefully “future proof”.

Switzerland
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