Nuckolls Z-101 & G3X - what to put on clearance / brownout bus?

I'm working to finalize an upgrade panel design that's been two years in the making, and I find myself going back & forth over what should be on the clearance delivery / brownout bus on Bob's new Z-101 architecture in a G3X, IFR panel.

If you were building a full-up dual-G3X plus GTN 650xi panel, what would you want on a clearance delivery bus? In other words, what all bits & bobs do you need to have online to call for a clearance & set up your flight plan prior to turning on the main bus for engine start?

And then, when you start the engine, what components are prone to restart due to low voltage? Instead of the TCW IBBS I see in a lot of these panels, I'm planning to use the TCW power stabilizer, which will provide up to 8A. I also have a GAD 27 in the mix, which can provide 3.5A of stabilized power if 8A isn't enough.

Finally, what do you absolutely want on pullable breakers vs. on fuses inaccessible during flight? Right now I have AP servos, pitch trim servo, and flap motor on breakers.

Thanks!

As far as the bus is concerned, don’t overthink it. KISS is a good principle to follow. I have the TCW IBBS that works great to keep the G3X powered during engine start with no fluctuations/reboots.

For pullable CB’s, I have alternator, pmag, elec trim, and AP servos. Everything else I have deemed non-critical to access in flight, therefore are on automotive fuse underneath panel.

This is what works for me, YMMV.

My panel has a version of the clearance delivery that's found on Z-101.

• Primary EFIS
• GNX-375
• Comm

The CD Switch is 1 over from the master..next to the ALT field breaker.

Edit: You can see the breakers I felt were necessary...the rest are fuses.

Seems way easier to buy a handheld comm to get a clearance. You can put the first couple of waypoints or the sid in the gps while the engine is warming up. At most airports, i can get my clearance and put in the first few waypoints before my engine is warm enough to take off. Seems the longest waiting is at the hold short line, waiting for departure clearance.

Larry

lr172 said:

Seems way easier to buy a handheld comm to get a clearance. You can put the first couple of waypoints or the sid in the gps while the engine is warming up. At most airports, i can get my clearance and put in the first few waypoints before my engine is warm enough to take off. Seems the longest waiting is at the hold short line, waiting for departure clearance.

Larry

Click to expand...

Yes, using a handheld would have been easier but now it’s done and I can take my time entering a flight plan or figuring out a route without drawing a lot of amps. It’s experimental, build what you want

lr172 said:

Seems way easier to buy a handheld comm to get a clearance. You can put the first couple of waypoints or the sid in the gps while the engine is warming up.

Click to expand...

Not a bad suggestion. I would however like to be able to look at XM weather before engine start, in addition to comms & flight plan setup.

Ignoring the clearance bus part of my question, for those of you with flying G3X panels, what devices should be protected from restarting due to brownouts during engine start? In the Z101 design, this bus can play one or both roles (CD and/or brownout). Or it can be left out entirely.