Avionics - Box Installation

I made the supports from 1”x1/2”x1/8” aluminium angle, spacing them to match the hole span on the GEA 24.

I match drilled two holes in each bracket for 1/8” rivets.

Having clecoed one end of the VPX brackets I match drilled the other ends to ensure a correct fit.

To allow easy removal of the units through the Avionics Bay Access Hatches I decided to use nutplates.

I don’t yet have a B&C LR3D Regulator for the standby alternator, but I made a foam model to check I’d be able to open the access door I’d planned.

Seems OK, so I went ahead and match drilled holes in the flange to attach the hinge.

Most of the rivets in the F-01455B Map Box Doubler had to be removed, and then replaced with nutplates …

… or flush rivets to allow the door to close and be secured with screws.

All the parts primed & painted ready for installation.

After riveting on the support brackets, I used AN3 bolts to attach the angles.

To accurately position the various boxes I used paper templates to mark the holes.

It took a bit of time to work out what hardware was needed to attach everything.

I wanted to use the minimum bolt lengths, but also have enough grip to ensure there was no thread in the holes.

Since the TCW Back Up Battery may well need removal during its life, rather than using nuts I attached nutplates to small pieces of aluminium.

This should make it easier to remove with the restricted access in front of the sub-panel.

All these boxes fitted as planned in FreeCad.

I decided to fit the Air Avionics AT 1 box on the outboard face of the F-01456-R FWD FUSE RIB.

I should be able to access this unit via the Regulator Door.

The transponder fits just fine under the access door, and there should be enough room for any switches required under the left display.

The regulator door will also allow access to the AT1.

OK … deep breath … wiring next!