[Captain_John]

Hey All,

I see that in the manual we are backing up the GDU 37x's, GEA 24, GSU 25, GAD 29 and the GMC 305 via their pin 2's.

My question is; Why are we backing up the GMC 305 and not the servos? Wouldn't the 305 be useless without the servos powered?

What am I missing? Why not either NOT back up the 305 OR power the servos along with it?

CJ

 

[Brantel]

One reason is to keep the FD display working....No GMC305, no FD.

I don't think I connected mine to the backup bus. I will have to check. Installed that thing in a hurry right before Osh 2013. I may change that if it is not because it would be handy to have the FD driven off of the internal flight plan if I lose main power. The external GPS is dead in that case.

I also don't power my PFD2 on the backup bus, don't want the extra draw for a screen that I most likely would not be using in the event of a power failure.

 

[MarkW]

If I am running out of juice I don't want the servos using what I have left.
I did not hook the GMC up to my E-Bus but it only draws .5ma so having the Flight Director like Brian says could be nice.
I also did not connect the PFD to the E-Bus.

 

[Captain_John]

Ok then... FD is a nice thing to have.

Given that, I am thinking of powering the 305 and the servos from the main battery on a "secondary bus". I call it that because it will be secondary to the VPX. It will be downstream of the master.

This will allow me to have the option to use the AP in any situation.

I would also like to put the comm portion of my 650 on the secondary bus as well. This way when the PS Engineering audio panel goes into failsafe mode, I will have the option of a comm as well.

Load shedding can be done individually if need be.

Perhaps putting pin 2 of the GDU 370 on the secondary bus would be good too then?

Thoughts?

CJ

 

[Brantel]

Yes my PFD1 and MFD are both on the backup bus.

Had my Gemini PFD on there as well. It's replacement has its own battery.