GTX 330 ES in a Twin

[N3322G]

Wondered if anybody has put this in a Twin Comanche yet and if so, where did it fit?

Our current transponder is the classic Collins TDR 950, one of the smallest in the industry.

The depth of the GTX is over 11 inches where the TDR is around 7 inches and is installed high in the center stack so if we decide to go that way, I don't know if it would fit.

Anyone with experience here?

[Don Nelson]

Pat, FWIW, I have the 327 in my B model twin, under the 340 Audio Panel. Had same in the 250. Don't know if 327 and 330 are same size. If I remember right, the transponder won't fit on top.
Best, Don

[Charles Schefer]

A GTX 330 ES is my current plan WRT ADS-B out. I prefer a 1090ES vs 978UAT for out. I have a GTX 327 currently. I think think the only issue may be the depth of the unit. The face plate of both units are the same size to my knowledge. This would explain Don's comment that it won't fit on top (sloping glare shield limits depth). I recall that years ago when some Cirrus aircraft with 327 units upgraded to 330 units the stack had to be rearranged and the 330 had to go on top (Cirrus stack is not under the glareshield). I recall the issue was the space available given the depth of the unit. I think on Garmin's site there are specs you can pull up including dimensions.

- Charles

[N3322G]

Thanks Charles and Don,

Since I was up in OKC to speak at the ICS banquet, with Chuck Stroh's help, I met with an experienced installer and he thinks we can swap the Collins TDR950 with the GTX ES 330. I brought cell phone pics and the audio panel is on top with the TDR under it and then the 530W. Turns out the 530W is the same depth as the GTX ES 330 so I can open the top and assess whether it will sit there or not, BEFORE I spend big bucks.

[Charles Schefer]

That sounds reasonable Pat, I don't think you'll have a problem unless they've run a lot of hard lines or tight wiring right behind that spot. I think the only place you'd likely have an issue is the top spot because of glareshield clearance. And... I think on the PA-30 C and PA-39 like you have there was even more room on the top based on the glareshield shape than what I have on the B model. Tho I have one of the "Ashby" glareshields so I'm not sure how that compares to stock.

- Charles

[N3322G]

Charles,

I actually have a small spacer at the top now, then the audio panel etc so I have my fingers crossed I can use the same transponder space. Like you said, depends upon whatever else is back there.