Garmin GTX 335 Question

[Maverick]

I am looking for my avionics and see that the Garmin GTX 335 transponder provides mode S, ADSB-Out, and GPS. My question is, how do you view the GPS? Does this transponder unit only work with EFIS? I do not want an EFIS. I plan to use good old steam gauges. I am unable to find information on how to display the GPS part of the unit and I can't find a means to write to Garmin to ask such questions.

Also, Is there a different solution? I'd really like to find a package that has com radio, txp, adsb, and a GPS bundled but it doesn't seem to be out there.

[PapuaPilot]

Great questions.

The GPS in the GTX 335 provides the WAAS position source for ADSB out. It isn't a GPS that can viewed or used for navigation.

You can use this as a stand alone transponder with steam gauges (without an EFIS), but it looks like you will need to buy the altitude encoder too.

There is no such thing as an all in one package like you mentioned. If you are doing steam gauges as a minimum you probably will want to get:
1. COM/intercom
2. Transponder/ADSB Out
3. GPS Navigator w/ Screen

[aviator79]

If you upgrade to a GTX 345, It will wirelessly stream GPS, ADAHRS, traffic, and weather to the device of your choice.

[Hoenshell]

Does anyone know if you could potentially use a single GTX 335/345 in two different airplanes? Could I purchase one unit that is capable of being programmed with tail number and then move them from one airplane to another? I've got a Cessna 172 that needs an ADS-B capable transponder and I'm working on building a IV Classic that will need one as well.

[aviator79]

Does anyone know if you could potentially use a single GTX 335/345 in two different airplanes?

You can edit the Fight ID pretty easily in the GTX 335/445. Swapping the hardware would be the bigger inconvenience.

Edit: I just read the Garmin manual and the only catch is that by default, the flight ID is not editable. A Garmin-authorized installer can configure the unit to make the Flight ID editable, in which case it is easily edited directly on the unit.

[Hoenshell]

I'm thinking for $3k to $5.5k (since I need the GPS) that I might be willing to put up with the inconvenience for a while.

[mr bill]

I have a GTX335 with built in GPS and Altitude Encoder for ADS-B out only. For ADS-B in I have a GDL 39-3D bluetoothed to a Garmin Aera 660, so I get other aircraft and weather. It all works well.

[Hoenshell]

In addition to the GDL 39, you can use the GDL 50 for ADS-B in and weather with the GTX 335. The GDL 52 ads Sirius XM if you have a Aera 796 that supports XM radio.

[PapuaPilot]

I don't think it is possible to do that. There is a lot more than a flight ID that must be programed into the ADSB unit that is specific to the aircraft.

The best answer would come from an avionics shop.

[Hoenshell]

Looking through an installation manual of the Garmin GTX 3X5 the flight ID can definitely be changed and there is some aircraft specific information such as category, length, width and speed; although, it doesn't allow for a specific values for any of these. Instead you choose <= 15 meters, <= 150 knots, etc. A Cessna 172 and a Kitfox are pretty similar in size, maybe enough that these values would be correct for both aircraft. You can also select unknown. From what I can tell only the Flight ID is the only value that is specific enough to really differentiate between a 172 and a Kitfox as far as ADS-B goes, but I'm probably wrong somewhere. I will see what kind of answer I get from an avionics shop, but I'm guessing no matter the feasibility the answer will be "no".

[jrevens]

It is my understanding that the dimensional information (length, distance of antenna from nose of aircraft, etc.) is there and useful mainly for large aircraft, on the ground position and spacing, etc. I would think that those values are relatively close to each other and unimportant between a 172 & a Kitfox.