Continued Panel and Electrical Work

I was all over the airplane this weekend, but my main focus was the ELT, Throttle Control, and Skyview network.  Basically I ran the Skyview network and all the ELT wiring through the fuse.  I didn’t realize how many wires needed to be run to support these two components.  I got them ran though through the passenger side of the fuse.  Also, I installed the panel control for the ELT and the internal speaker that is used for testing and alerts the occupants when the ELT is active.  All in all I got lots done and even though not a lot of pictures to show for it, I set myself up for some good work sessions in the next few days.

I am using the ACK 406 ELT and it is a pain to install because of the amount of wiring needed to set this thing up.  First off, the unit requires 3 batteries as well as power supply from the aircraft.  It is TSO’d, (meaning approved by the Gov) but seems to be crazy inefficient.  There is a full telephone line (wire) that is used to communicate from the panel to the unit, as well as a GPS signal line (which makes sense) from the GPS, then also power and ground lines which all run from behind the panel to the ELT.   Battery in the speaker, battery in the panel switch, and battery in the ELT.   There is also a test line that is supposed to run to the forward cabin, but I am going to short it right back by the ELT.  And then I need to run the antenna cable before it is all over.   Pretty disappointing, but I guess it is an important safety feature as this one has GPS as well as the 121.5 emergency channel broadcasting..  If I ever need it I will be glad I went through all this trouble.  ;-)

Control Cables

In the last week or so I have been working on odds and ends..  Nothing very glamorous, but  still making progress.   I received a braided ground strap, that fits great between the engine and the battery terminal.  This is needed to ground the engine since the starter grounds directly through the engine case. (sorry for sideways photo)  Also, I did some final paint, including the FAB (induction box) and engine controls bracket.  With the engine control bracket painted I installed the prop and mixture controls and hopefully won’t have to remove them ever again.  I need to wait on installing the throttle control, since it has to go through the center tunnel cover which hasn't been drilled yet.

I chose to run both Prop and Mixture through the center pedal support which worked out great.   A grommet with a  large hole fit both cables and holds them secure.  Also ran the Alt Engine Air cable through the bracket.

Finally I installed and cut the parking brake cable.  Fits nicely and functions very smooth.  I am really glad I did the parking brake.  It was easy to install and will be super useful down the road.  Also note my location is such that I can reach in while standing outside the plane to release the parking brake !  It always bothers me on planes where you have to jump in side or climb on the wing to release the brake.

Avionics Fired up and no smoke !

I am not out of the woods yet, but I did reach a little milestone this weekend where I fired up the avionics and kept all the smoke in the wires.  Everything went well, although I used my back up circuits to power most of the avionics..  But it’s good to know that the backups work.

In my case I am choosing to back up 4 instruments in case of an electrical problem.  The Skyview has its own back up battery so I am not going to back that one up.  My theory on back up is only back up for a single failure..  Backing up for multiple failures is not prudent in most aviation circumstances.   A multiple failure would be something like backing up the backup battery of the Skyview.


The four instruments I am backing up in the case of a total electrical failure are below.  I chose these instruments because in the event of a failure, if they are the only ones available on battery power I could still get safely to a safe landing spot. 

TruTrak Gemini

Audio Panel

GTN 650 Com

GTN 650 Nav

Since I have a VP-X I had to separately isolate all four circuits so I am using a set of diodes similar to Jason’s project.  You can find his build site from the home page of my site.  Anyway, these are basically like one way electrical valves that keep electricity from back feeding the entire system when the essentials bus is turned on.  You don’t want to back feed the whole system because it would drain the battery too fast and also probably blow the switch because my e-bus switch is only a 30 amp switch.  Anyway, long story short when I flip the e-bus switch it bypasses the VP-X and runs power straight from a connection on the battery to these four devices.  This would be necessary in case of a total VP-X failure, or a master contactor failure or any wiring failure upstream of the VP-X.   So there are lots of reasons to have this safety feature.

In this pic, you can see the diodes where you have the Gemini and audio panel on the top and the GTN Com and Nav on the bottom.  I will need to label them and clean them up a bit..

Panel and Avionics

I think I am making progress, but sometimes it’s hard to tell.   Maybe over my head a bit right now with wires, but soon they will find their correct path.  One wire at a time like everyone tells me, but if that is the case then where did all these hundreds of wires come from..   ;-)

I can’t really explain all the stuff I did since I am kind of in autopilot and just cranking away at the next item that calls my attention..  I will do my best to cover what happened this weekend.  I found good routing for the Arinc wiring but haven’t connected it yet, also included the pilot mic and headset wiring with this path..   I installed the harnesses to the back of the radio trays and wired up the antennas to the GTN.  Installed the Gemini and fired it up for the first time.  Riveted the frame around the panel so that I don’t have to worry about this later.   Basically my panel is completely cut except for the seat heat switches, ELT, and annunciators.  I think I am pretty happy how it is turning out.  Eventually it will be a dark grey, probably same color as the carpets when I get them.  I also started hooking up the Dynon D-37 pin connector which is the main backbone of the Dynon.   I connected the GPS antenna, also ran the wiring from the Dynon to the VP-X.  All power and ground wires are ran for the Skyview but I am too chicken to turn it on right  now.    ;-)

Panel Progress

Continuing to make progress, I have now cut the panel for the Sky view and almost all my other components.   At this point I only have two breaker switches to install and the cutout for the ELT switch left to go.   I also mounted nutplates to my Com 2 (hidden) com that mounts behind (on the forward side of) the subpanel.  These nutplates will allow me to remove the unit with a screwdriver from the easily accessible front of the subpanel.

Also, I cut into the subpanel for the recess on the GTN650 and reinforced it as necessary.  The sides of the cutout will have additional angles that help support the mounting tray..  The top has an additional angle riveted in place and the bottom has a 90 degree bend from the subpanel itself adding strength.   I found a great way to include the Sky View mounting bolts with the supporting rib that had to be relocated to make room for the Sky View.  Also, the rear of this rib gets riveted into a section between the "hat" section no the forward part of the subpanel.  Everything is fitting together pretty well at this point, definitely doing all I can to think ahead as I go through this process.  Don't worry about all those ink lines and general look of the metal, this will be cleaned up and look beautiful when complete.  

Cutting deep into the Panel

Over the weekend I used some angle to create a frame for the radio stack then measured out where to start cutting the panel.  I had to consider the substructure very significantly before cutting.  Everything has to fit together and the GTN 650 goes through the sub panel, so care needed to be taken.   I think I got it perfect, I will need to work on the Skyview cutout and the sub panel, before everything is solidified, but for now things are looking good.   I cut the hole for the radio stack a bit small so that the case frames seal up nicely, but I had to file out some clearance areas so that the 650 and the PAR-100EX fit with needed clearance.