G3X Redundancy Question

[Rallylancer122]

Hi Folks,

First off, sorry if this has been gone over already. I searched it, but there is about one million threads on the G3x so I may not have seen it.

I've got a question regarding redundancy on the G3X. I'd like to go with a single 10" display (including engine) instead of two of the 7 inch displays. I'm assuming the G3X is designed to 10 to the minus whatever failure criteria, but there's things like circuit breakers, wiring issues, shorts, etc... I know that the 430's and 530's actually have two separate power inputs, one for the GPS and one for the nav/com. Is the G3X setup this way? How do they handle redundancy on a single display?

Yes, there's backup flight instruments, but if you have a single 10" display with the engine gauges your are losing primary flight instruments, engine, and MFD. That's a lot. I know, I know, put in 2 displays. Ok, but I'd like to run out the single option anyway if for no other reason than to validate the extra cost of the 2nd display.

Thanks,
DEM

[Walt]

Go with 2 displays for sure, with the option for 3 with dual ADAHRS, add a stand alone CGR30 engine monitor and G5 just in case

[g3xpert]

Hi DEM,

Great question! Each G3X display (GDU) has an 'Aircraft Power 1' and 'Aircraft Power 2' input. You can wire the primary master/avionics bus on power input 1 with a backup battery or other power source on power input 2 for the redundancy you desire.

This backup electrical source can also power the input '2' on flight/engine critical components such as the GSU25 ADHRS and GEA24 EIS units so you do not lose that data.

Best Regards,

Brad

[David Carter]

I would not install just a single G3X display. You need a backup in case the GDU (display) or the GSU (ADAHRS) fails. Add a G5 have a backup display, a backup ADAHRS, and a 4-hour backup battery.

[leok]

DEM,

You didn't mention your mission. If IFR capable I would add the second display. If VFR, a G5 with the battery for back up airspeed, altitude and attitude and you should be fine.

If you fly with an iPad or such for charts, with the G5 you have back up for everything except engine instruments. IMHO a person should be able to get the aircraft to a runway VFR without reference to engine instruments in a pinch.

Just my 2 cents.

[Rallylancer122]

Thanks Brad. Dual power inputs likely covers the majority of potential failures. I was curious if Garmin had done something tricky like power each half the screen so that you didn't lose it all in one shot.

For a number of reasons I'm not real keen on dual 7 inch displays. A G5 backup is probably the best option.

DEM

[Scott Hersha]

I had a G3X primary EFIS, powered by my primary bus (1) and my Aux bus (2), and a G5 Secondary PFD, powered by my primary bus, and an internal backup battery. This gives you direct systems redundancy (EFIS/PFD) and secondary systems redundancy (electrical system supply).

[g3xpert]

Originally Posted by Rallylancer122

Thanks Brad. Dual power inputs likely covers the majority of potential failures. I was curious if Garmin had done something tricky like power each half the screen so that you didn't lose it all in one shot.

For a number of reasons I'm not real keen on dual 7 inch displays. A G5 backup is probably the best option.

DEM

Each power input powers the entire unit, rather than individual boards on the unit.

A single GDU paired with a G5 offers quite a bit of redundancy and protection against loss of primary flight instrumentation. The G5 has a dissimilar ADAHRS within the unit itself, to lessen the likelihood of a common mode failure between it and the GSU 25 ADAHRS from the G3X Touch. You can connect an optional backup battery directly to the G5. In this case, if you were to lose your entire electrical system, the G5 would still be able to run under its own power and provide you with flight instrumentation.

Thanks,

Justin

[avrojockey]

I would say do with what your most comfortable after risk analysis based on your mission, potential failure states to include severity and potential.

For me this was 2 G3X screens and dual AHRS, and a 3rd AHRS in the GPS 175 sending attitude info to my iPad in case things got really bad. All this with electrical design redundancy and protection since everything is electric. This is for an IFR bird.

For VFR only - Single G3X 10" screen or 2 - 7" screens, single AHRS, iPad and an analog ASI. You could fry everything and land safely VFR off the old-school ASI and the iPad.

[jliltd]

Your original post didn't disclose what model of RV, but I assume you are an RV-8. In a tandem seat RV a dual screen system can get busy and make the install look forced and ugly. One 10" display suits me better than two 7" displays mainly due to the screen to bezel ratio. The smaller displays have the same bezel so it exacerbates the loss of real estate. It's easy to get a lot of input here about going with two screens but I think most of those are coming from the side by side RV crowd. As G3Xpert said above, the G5 combined into a single GDU system is a very robust combination and leaves room for standard sized avionics like an IFR Navigator, Audio Panel, AP controller etc. I have an RV-8 with an awesome single-screen 10" G3X Touch with dual GSU 25 ADHARS units (thanks Walt!). I plan on adding a G5 soon so that will give me a $1,500 barometer setting knob while adding a third ADHARS.