denopa wrote:
kept it separate when I did my panel for two reasons:I quite like the custom fields you would loose if you used the GTN to control the GTX
If I loose my GTN, I’d loose my ability to squawk 7600
I have the best of both worlds by having a GTX345 on the RH side of the cockpit, a bit out of the way, but with GTN remote control enabled. I can control the transponder from either unit.
Peter wrote:
Personally I would be concerned about a single point of failure, via a failure of the LCD panel. Then you lose a whole load of functionality in one go.
I’d guess for flights where you really need the transponder (i.e. IFR in controlled airspace) you most likely have two GTNs in your plane anyways so that you have a backup LCD panel for operation. The transponder is a single point of failure anyways in most planes (haven’t seen a new installation of dual transponders for redundancy for quite a while – guess that is an overcome concept since we have solid state transponders which are quite reliable…)
denopa wrote:
I quite like the custom fields you would loose if you used the GTN to control the GTX
That’s interesting – and perhaps should go into a new thread… But what do you show on your custom fields?
In my standard configuration I have the 650 on the default nav page that gives me six data fields (plus next wp, CDI, frequencies, etc.) and the 750 on map view with 4 more data fields (one in each corner of the map). The only one I use on the 750 is GPS-Alt. So I actually have 3 data fields left that I don’t really need even though one of the buttons in the top strip of the 750 is TRX.
But I have to admit I’m not an expert on what thee boxes could really do for me and therefore reading your post makes me think if I’m missing out something ….
The main reason not to have a remote transponder is the danger of multiple failures from one unit pushing up the workload, after all a single GTN failure would result in the lost of GPS/VHF NAV, VHF COMS, Transponder, ADSB, fuel flow air data and ELT Position data.
While some of these functions are covered by the second unit most aircraft only have a NAV/COM as the #2 box. So keeping the ability to control the transponder independently is a big advantage.
For those with two GTN units this single point of failure goes away, the GTX 33 is quite a heavy unit so remote mounting to take advantage of the W&B situation is useful but the main advantage is to uncluttered the panel.
At the lighter end of the market the superb remote transponder & VHF COM offerings from trig offer ease of mounting in small aircraft.
Malibuflyer wrote:
I’d guess for flights where you really need the transponder (i.e. IFR in controlled airspace) you most likely have two GTNs in your plane anyways so that you have a backup LCD panel for operation.
I very much doubt that!
In any case, as long as panel space it not an issue, I prefer to have separate controls for everything. Controlling the transponder (or the audio panel) from a GTN or G3X does not add any value in terms of functionality or human factors. The only advantage would be in saving panel space.
The number of squawk changes varies with the country.
When VFR in France, you will change your squawk twice every 5-15 minutes (ATC/FIS insists on 7000 then new code). It makes a txp keyboard very valuable 
That’s interesting – and perhaps should go into a new thread… But what do you show on your custom fields?
My 650 shows Traffic if I’m VFR and Nearest Airport if I’m IFR (that’s one of two mental triggers I use to switch myself from the two modes, which really require very different behaviour from the pilot).
On the GTN750 the top two fields show ETA and Time to Destination (more for the benefit of my pax than myself). The 4 fields on the map are bearing and track (meant as a back up if I lose my HSI), Vertical Speed Required and Time to Descent.
I already have track and vertical speed required on the G500 so I could use those for something else, especially VSR. GPS Alt could be good but I already have that on the G500. I used to have MSA but the way Garmin calculates that is way too conservative to be useful.
Malibuflyer wrote:
But what do you show on your custom fields?
I show the “FPM required” for VNAV. Then, I use the rest for buttons, actually.
