GNC-255A w/ G3X wiring questions

[Zuldarin]

Greetings all, I am not an electrical guru and I am installing a GNC-255A nav/com in my 9A. Stein originally built my avionics wiring harness and did an excellent job of insulating me from the mess of trying to figure out what pins need to go in what hole. However, Stein's team is busy (great news) and my first flight is coming up quickly so I opted to have him send me the radio without updating the wiring harness. Now I see all the pins that potentially need hooked up and am wondering if I could run a few questions by you all in hopes of getting this radio installed "with" the magic smoke still in tact.

First, I do not have an audio panel and this is my only radio. I do have ARINC (GAD 29) for my GPS-400 and a G3X Touch. So, here are my questions.

1. The comm pin out lists an RS-232 interface. Should this be hooked up to anything and if so what is the purpose/benefit?

2. The install manual lists 5 power inputs for both comm and nav and says that all 5 must be hooked up. However it also shows several grounds but does not say whether or not they all have to be hooked up. Looking at the wiring diagram Stein sent me I see a few grounds on other pieces of equipment that are not hooked up. If its not specifically pointed out, do I need to hook up all grounds or just one?

3. There are a ton of outputs on the nav side for various VOR/ILS/DME signals. I am only planning on using my GDU-460 display HSI. Do I need to hook up anything more than the ARINC output to the GAD-29?

Thanks for any help you all can provide!

Darin

 

[g3xpert]

Greetings all, I am not an electrical guru and I am installing a GNC-255A nav/com in my 9A. Stein originally built my avionics wiring harness and did an excellent job of insulating me from the mess of trying to figure out what pins need to go in what hole. However, Stein's team is busy (great news) and my first flight is coming up quickly so I opted to have him send me the radio without updating the wiring harness. Now I see all the pins that potentially need hooked up and am wondering if I could run a few questions by you all in hopes of getting this radio installed "with" the magic smoke still in tact.

First, I do not have an audio panel and this is my only radio. I do have ARINC (GAD 29) for my GPS-400 and a G3X Touch. So, here are my questions.

1. The comm pin out lists an RS-232 interface. Should this be hooked up to anything and if so what is the purpose/benefit?

2. The install manual lists 5 power inputs for both comm and nav and says that all 5 must be hooked up. However it also shows several grounds but does not say whether or not they all have to be hooked up. Looking at the wiring diagram Stein sent me I see a few grounds on other pieces of equipment that are not hooked up. If its not specifically pointed out, do I need to hook up all grounds or just one?

3. There are a ton of outputs on the nav side for various VOR/ILS/DME signals. I am only planning on using my GDU-460 display HSI. Do I need to hook up anything more than the ARINC output to the GAD-29?

Thanks for any help you all can provide!

Darin

Hello Darin,

1. Yes, you should wire and configure the RS-232 interface between the GDU 460 and the GNC 255 per page 21-9 of the Rev. Q G3X Installation Manual. Not only does it support VOR/LOC/ILS navigation, but it allows you to touch tune the GNC 255 COM radio from the GDU 460.

2. For power ground, the GNC 255 installation manual shows aircraft ground being connected to pins 37, 38, and 40 of connector P2001 and pins 61 and 62 of connector P2002.

3. The G3X Touch system only requires the RS-232 serial interface to the GNC 255. No connection to the GAD 29 is required.

Let us know if you have additional questions.

Thanks,
Steve

 

[Zuldarin]

Thank you Steve, you guys make it almost too easy.

Darin