The wiring really never ends...

I terminated the EFII battery cables and connected the batteries to those plus the main bus, secured the whole thing with wax lacing, and attached the hall effect sensors with the mounts I had 3D printed:

Batteries installed and connected

Probably unnecessary (they were already a tight fit), but I also ran some wax lacing to secure the sensor mounts more firmly:

Hall effect sensor brackets secured around battery cables

Another tense moment turning it on, but everything worked! Well, everything except the hall effect sensors, which were giving no reading in spite of being connected to the G3X's GP6/GP7 inputs. A lot of troubleshooting later, and I realized that even in Stein's original wiring diagram, they missed the fact that the "LO" side of that connection also needs to be connected to a ground pin (per Garmin's manual: "When using the GP6 and GP7 inputs for general-purpose voltage sensing, including position sensors and user-defined analog parameters, the corresponding GP6 LO or GP7 LO pin must be connected to ground."):

SteinAir's original wiring diagram, without a connection between GP6/GP7 LO and GND

Instead of adding splices to both LOs, I simply moved the sensors to GP3/GP4 which already have the LOs internally connected to GND (and are actually the pins that show up in Garmin's manual for this connection):

My updated wiring diagram, moving the hall effect sensors to GP3/GP4

Moving to the other inputs required a bit of surgery to split those +5V pins again (but to the naysayers that say that a box full of random pieces of wire is useless, I used a white/orange piece with the socket for this):

Hall effect connectors on the GEA24 side after modification to use GP3/4 instead

Once plugged in, I immediately got a reading - however, the reading was something like -13A, which seemed wrong. I then realized Garmin's documentation doesn't match Amploc's for that sensor - Garmin says the sensor should read 2.5V at 0A, however the KEY100 documentaiton says it should read 5V/2.2=2.27V. At 15.9mV/A, that 230mV difference makes it read a significantly wrong value - I calculated the offset would be about -14A, but then I also realized that these must have significant variability, because 8.8/8.9A was the actual offset I had to apply:

Offset that had to be configured for KEY100 sensors

Proper current readings after adjusting the calibration

I had previously made a small hole on the tunnel cover to run wires into the tunnel from the panel, thinking that I could just de-pin connectors and pull the wires out when I needed to remove that cover - but it became apparent that assembling and taking apart the GHA15 connector is more painful that I expected, so I enlarged that hole enough to let the whole connector go through:

Larger hole on the tunnel cover for the GHA15 connector to go through

Tunnel cover with wires going through it (no edge protection just yet)

I also took the opportunity to trim and terminate the center console wiring (I honestly wish I had just shipped the whole plane to Stein to get those lengths right from the start), and changed the gender of the pax connector so they can't be accidentally swapped - I'll later add some Clickbonds cable ties to secure it alongside the engine cables and underneath the throttle quadrant:

Audio wires running underneath the throttle quadrant

Wires running through the center console for pilot and passenger audio

Pilot audio connections inside the center console

I had planned to run the flap wires over the top of the tunnel, but then changed my mind as it was easier to secure the whole thing by running it through the side (plus I had already added Clickbond fasteners near the flap torque tube for them):

Flap motor wires running near the flap torque tube

For the pitch trim motor, I had (way back when I built the tailcone) added a beefy 28-pin connector, thinking of the ELT connection plus anything else that would go in that area. I now realize that was way overkill, plus the connector was too far from the trim motor, so I drilled out the rivets that attached it, and replaced it with a simple Molex SL connector:

Pitch trim motor with previous CPC connector (overkill)

Pitch trim motor with Molex SL connector

More wiring to come - the next big thing is finishing up and securing the main panel bundles for good, and terminating the wing root and stick grip CPC connectors.

Time lapse:


Total avionics rivets: 177
Total avionics time: 309.2h

Baffling baffle blabber

For a change, I decided to work on something other than avionics, and got started on the engine baffles, which are a small puzzle of odd-shaped parts:

Cylinder 6 baffles sitting in place

The left aft case baffle is pretty hard to get in place, but I realized that if I just bent the little tab a bit forward, it clears the engine mount and falls in place:

Attempting to insert the left aft case baffle

Bent tab which makes the left aft case easier to install

It was then time to make the baffles fit around the cylinder head gaskets, which required quite a bit of trimming:

Cylinder baffle marked for trimming

Cylinder baffle marked for trimming

After a lot of trimming and deburring, I got them all to fit nicely around the cylinder head gaskets:

Trimmed cylinder baffle sitting around the cylinder gasket

I also match-drilled the oil cooler bracket (I don't really understand why it's called that, since the oil cooler goes on the firewall):

Oil cooler bracket clecoed in place

Oil cooler bracket match-drilled to the aft baffle

I also detected a bit of interference with the System32 injector, which I'll have to trim the baffle for:

Interference between the baffle and the #5 injector

The next steps on the baffle require the cowling to be in place (to trim the top of the baffles), which in turn requires the propeller to be installed...so this section is now on hold until all that happens.

Time lapse:


Total cowl baffle time: 13.4h

Checklist editor

I was not very happy the existing options to edit checklists for the G3X (for one, because they were OS-specific), so I ended up making my own, web-based, and published it as open source here (it's usable directly from GitHub pages, just click the highlighted link after reading the disclaimer).

N425RP's checklist on the checklist editor

This was a fun little project, and I got to exercise some of what I knew about Angular and Typescript (and, as a backend developer, ugh, CSS). It also seemed pretty easy to do, so I added support for other checklist formats, like Dynon, AFS (almost the same as Dynon), and GRT.

This is a very first version, and as I said I'm not a web developer, so bug reports, pull requests, or any type of feedback, are more than welcome! 


The wiring never ends

I pulled most wires through the wing root openings, and trimmed some of them:

Wires coming out of the wing root openings, some of them very long

I ran the trimmed part of the GMU bundle through the wing (I'll adjust its length much later when I actually attach the GMU to the wingtip):

GMU wire bundle coming out into the wingtip

I had previously (~7 years ago) attached a circular connector to the roll trim servo, which was very bulky - I decided to replace it with a much smaller Molex SL connector, and terminated the wing side of those wires to connect it:

Roll trim servo with "mini" CPC connector

Roll trim servo with Molex SL connector

Roll trim servo connector in the wing

On the ECU connectors, I noticed the connectors had some slack because the thumb screws were bottoming out on the holes before fully seating the connectors, so I added some #4 washers to those (which was unfortunately a pain since the wiring was all secured in place already):

EFII ECU connectors with slack between thumb screw and the connector

EFIS ECU connectors after adding lock washers under the thumb screws

We then attached Clickbonds to secure various wire bundles - within the tunnel, on the subpanel, and in the tailcone:

Click Bond fasteners for securing fuel pump, GHA15 and stick grip wires

Click Bond fasteners for securing stick grip wires

Click Bond fastener to hold right-side breakpoint connector wires and coax cables

Click Bond fastener to hold left-side breakpoint connector wires

For removing the primer where the Clickbonds attach, we found out that we can use the Dremel with a 512E abrasive buff does a pretty good job and is a lot quicker and easier than manually sanding with ScrotchBrite:

Removing primer with the Dremel, for installing Click Bond cable fasteners

With that in place, I finally wired the GHA15, and then tested it (both on the G3X and by connecting the USB pigtail to a computer):

GHA15 connector and wire bundle routing

Wired GHA15 connector

G3X screen showing an AGL reading

GHA15 being properly detected over USB

The GHA15 connector is a Deutsch connector, which requires that sockets be inserted in all holes, and those without a wire need to have these little sealing plugs inserted on top of the socket (as if it isn't hard enough to insert a socket that has a wire attached to it - this required quite a bit of patience to complete):

Inserting sockets into all GHA15 cavities

Deutsch sealing plugs, which get inserted atop the empty sockets, "butt first"

GHA15 connector with all sealing plugs inserted

I also wired the fuel pumps:

Fuel pump wiring

Fuel pump wire route in the tunnel

(I also did the initial routing and trimming of the stick grip wires, but still need to attach connectors, bundle the wires with a sleeve, etc.)

I attached the EFII cables to the firewall, and realized that most of them are much longer than I'll need, so I ordered pins/sockets for shortening them:

EFII FWF cables (as provided)

Finally, I spent some time configuring logic signals on the G3X:

RPM logic signal setting on the G3X

Here's a summary of how I ended up configuring them, for now:
  • MAP ranges:
    • Normal range: Green 10-29 psi, Yellow 29-32 psi
    • When oil too cold or too hot: Green 5-15, Yellow+Alert 15-25, Red+Alert 25-32
    • When RPM 1800-1900: Green 10-25, Yellow+Alert 25-32
    • When RPM 1900-2000: Green 10-25.7, Yellow+Alert 25.7-32
    • When RPM 2000-2100: Green 10-26.6, Yellow+Alert 26.6-32
    • When RPM 2100-2200: Green 10-27.6, Yellow+Alert 27.6-32
  • Rudder trim:
    • Normal range: none
    • During takeoff (MAP >= 20 psi, IAS < 50 KT): Green -10-+20, Yellow otherwise
  • AFR:
    • Normal range: Green 12-16, Yellow 10-12 and 16-20
    • During takeoff: same, but alert for yellow

  • Battery current sensors:
    • Normal range: Red+Alert -100 - -30 and 60-100, Yellow+Alert -30 - 0, Yellow 30-60, Green 0-30, White Line at 0
    • When starting (1-500 RPM): Yellow -90-0
    • When RPM 500-1500 (alternator may not have enough output): Yellow -15 - 0
  • Backup battery:
    • Normal range: Red+Alert 8-10, Yellow+Alert 10-12.5, Green 12.5-14.8, Red+Alert 14.8-16
    • Charging (main bus at 13.5-14.8V): Yellow+Alert 10-13.5, Green 13.5-14.8
The MAP+RPM ones are trying to approximate the "oversquare" limitation from Lycoming's manual:

Lycoming graph for the IO-540-D series, showing the limiting manifold pressure for continuous operation

Unfortunately, the VP-X inputs, like pitch trim position, roll trim position, flap posiiton, etc. can't be used for logic signals - so I can't have a flaps speed or pitch trim position on takeoff alert (which are two of the 3 examples on Garmin's manual).

Time lapse:


Total avionics rivets: 177
Total avionics time: 295.3h

More avionics progress

The CAN bus issue turned out to be very simple to fix - I was plugging Garmin's GSA28 removal adapter to the intermediate breakout connector behind the panel, but turns out that only acts as a terminator if pins 3 and 4 are connected together (I missed that detail on the manual) - adding that jumper got everything working, and I then spent a lot of time updating, testing and configuring the panel:

Termination jumper between pins 3 and 4 of the roll servo breakout connector

In the process I also found out that the White Lightning power supply I'm using has an auto-shutoff (by default, after 2.5h), but luckily that didn't happen in the middle of any of the updates:

White Lightning external power supply plugged in

I also updated the light switch labels for the Ziptip Vegas (some day when I make v2 of the panel inserts I'll have the actual engravings updated, as well as adding a dimming/maintenance switch):

Updated light switch labels for the Ziptip Vegas

I also trimmed the bottom part of the center panel to run engine cables and wires underneath it, making it roughtly 1/4" narrower than the center console that mates against it:

Bottom center panel marked where the center console joins it (arrows) and offset for trimming

Trimmed bottom center panel

I then connected the baggage light:

Baggage light connected and turned on

We installed the GHA15 radar altimeter, roughly underneath the fuel valve - this gives a couple feet of distance from the GA58 TAS antenna (plus the GHA15 operates at 24GHz, so ~23 harmonics apart from the GA58 which transmits at 1030MHz), and the 120-degree cone just barely clears the landing gear:

GHA15 installed underneath fuel valve

GHA15 attached to bottom skin

I installed the roll servo in place and ran its wires through the wing.

Roll AP servo installed in the wing

To connect the wing wiring, my plan is to install CPCs at the wing root, so I drilled the holes for those:

Left-side wing root connector holes

Right-side wing root connector holes

For fuel quantity sensors, the connection is right at the wing root, so no connector is needed, I just made a hole for the single wire to go through:

Fuel quantity wire coming out of the wing root area

I also ran the light wires through the wings, which was very easy to do with the conduits. I attached the Vegas Ziptip Molex pins, but will wait until the tips are here to attach the connectors so I know the right length and can add some sleeving to them:

Wingtip wires running through the wing conduits

Molex sockets for Aveo Ziptip Vegas

The overhead console switch pod was a really tight fit around the brace nuts, so I had to trim it slightly:

Interference between the Aerosport switch pod and the brace nuts

Trimmed switch pod to clear brace nuts

Switch pod clear of the brace nuts after trimming

Last but not least, I attached the EFII connectors to the firewall and tied the wire bundle together to avoid hitting anything:

EFII wire bundle and connectors attached to the firewall

EFII firewall connectors in place


Time lapse:


Total avionics rivets: 177
Total avionics time: 281.9h